Mil Std 150a

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MIL-ST&-150A 12 Moy W9

ARMED ORCES UPPLY UPPORT ENTER WASHINGTON 5, . .

Photographic Lenses

MIL-STD-150A

1. hi s tandard as ee n pproved y he Department f Defense an d s mandatory or se y he Departments f he Army, he avy,

an d th e Air Force, effective 12 May 1959.

2 . n accordance with established procedure, the Signal Corps, Bureau of Aeronautics, nd Air Force av e een esignated s Army-Navy-Air

Force custodians of this standard.

3. rovisions of this standard re th e subject of nternational standardization greement When evision r ancellation f his tandard s proposed, he departmental ustodians will nform heir espective e- partmental tandardization ffices o hat ppropriate ction ay e taken especting the nternational greement concerned.

A ecommended orrections, dditions r eletions hould e d- dressed^ he Standardization ivision, Armed orces upply upport

Center, Washington 5, D. .

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PLEASE CHECK THE APPROPRIATE BLOCK BELOW: °r I copies are being forwarded. ndicate whether Statement A, B, C, D, E, F, or X applies.

CM CM

LJ D IS TR IB U TION S TATEM EN T A: AP P R OV ED FO R PUBLIC RELEASE: DISTRIBUTION IS UNLIMITED

C H D IS TR IB U TION S TATEM EN T B: D IS TR IB U TION AU TH OR IZ ED T O U.S. G O V E R N M E N T A G E N C I E S

O N L Y ; (Indicate Reason an d Date), T H E R R E Q U E S T S FO R THIS

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CD D IS TR IB U TION S TATEM EN T D: D IS TR IB U TION AU TH OR IZ ED T O DoD AN D U.S. DoD C O N T R A C T O R S * '

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DoD AU TH OR ITY .

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AN D PRIVATE INDIVIDUALS O R E N T E R P R I S E S ELIGIBLE T O O B T A I N E X P O R T - C O N T R O L L E D

TECH N ICAL DATA IN ACCOR D AN CE WITH Do D DIRECTIVE 5230.25, W ITH H OLD IN G O F

UNCLASSIFIED TECH N ICAL DATA F R O M PUBLIC D I S C L O S U R E , 6 N ov 98 4 (Indicate date of determination).

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I This document wa s previously forwarded to DTIC on date) an d the

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I It will be published at a later date. Enter approximate date, if known). ,. I_J Other. (Give Reason) ///// iL**- /ribution Statements on Technical Dojriiments," 18 Mar 8 7,

described briefly above. echnical Documents must be assigned distribution statements

Do D Directive 523 0 . 24 , "Distribution Statements on Tecfink&l Doj^ments," 18 Mar 8 7, contains seven distribution statements, as

Print or Type Name

Authorized Signature/Date elephone Number

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MIL-STD-150A 12 May 95 9

CONTENTS Pag»

L S C O P E _ 1.1 U R P O S E

1. 2 LASSIFICATION Types of Lenses

Type I — Aerial Reconnaissance Type II — Aerial Mapping .'. . Type III — General Photographic . ZZZZZType T V — Process

Type V — Motion Picture CameraType V I _EnlargerType V II _Projection .Type VIII — Photomicrographic Type IX — Portrait Type X — ViewfinderType X I — CondenserType Xu — Copying- 2 Type XIII — Microphotogrraphie.. . 2 Type IV — Recording 2

2 . EFERENCED D O C U M E N T S 2

2 .1 O T APPLICABLE 2

3. EFINITIONS 2

3.1 X E S , P O I N T S , AN D D I S T A N C E S 3.1.1 ptical xis 3 . L2 xis of best definition . . ' . . ' . 3.1.2.1 lane of best definition 3.1.2.1.1 lane of best average definition

over the picture area Field tilt ZZZZZ ZZZZZZ

3.1.2.2 est principal focus 8.1.3 echanical axis

3.1.3.1 lange ilt ZZZ Z1 Z"." "Z." .ZZ17"'"Z".7" 3 5.1.5.2 lane of the receiver

3.1.2.3.1 ocai tnt ZZZZZZZZZZZ "Z Z" Equivalent ocal ength

Calibrated focal length ZZ .'.'

Back focal distanceFlange focal distance

3.1.8 ront focal distance 5.1.9 ront vertex back ocal istance3.1.10 elephoto ratio

til

S.l .2.1.2

3.1.4 3.1.5

3.1.6 8.1.7

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6 6

MIUSTD-150A 12 M ay 959

Pag»

4 S.l.ll epth of f o cus and depth of field 3.2 PERTURE AND RELATED QUANTITIES S5.1 Lens peed ' " ' 355 perture ratio 355 Effective aperture 3.2.4 lear aperture 3.2.5 elative perture8.2.5.1 -number 3.2.6 -stop nd -number35.6.1 rea weighted average T-number 3.2.7 r o n t perating perture3.2.8 ea r perating perture

3.3 O N S T R U C T I O N A L FEATURES 3.3.1 ptical ystem 3.3.2 ember

3.35 omponent3.3.4 lement 3.3.5 ron t of photographic lens35.6 ac k of ho togra phic lens 85.7 am e of design 35.8 elephoto 35.9 lass types

3. 4 E C H A N I C A L AND STRUCTURAL FEATURES 3.4.1 Cell " 3.45 arrel ~ ' . 3.45 Cone 3.4.4 en s iaphragm

3.4.5 ris diaphragm contro l3.4.6 arfocalized3.4.7 panner wrench openings .-

3.5 IELD F VIEW

3.6 PTI CA L C H A R A C T E R I S T I C S J

3.6.1 mage uality " " 3.65 esolving power8.6.2 .1 hotograph i c esolving o w er 3.6.2 .2 isual esolving o w e r 3.6.25 rojected photogra phic resolving power3.6.2.4 rojected visual resolving power

3.6.2 .5 rea weighted average resolution8.65 stigmatism and curvature of field Q

8.6.4 o lor orrect ion 0

8.6.4.1 ongitudinal chroma t i c aberration8.6.5 agnificat ion 0

8.6.5.1 araxial magnification

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MIL-STD-150A 12 May 1W

Pag*

11 8.6.5.2 alibrated magnification *

3.6.6 istortion

ZZ 1 2 2 2 2 2 3 3 3 3 4

.. . 4 4

4 ' 4

3.6 .6 .1 adial istortion 8.6.6.2 angential distortion 3.6 .6 .3 rrors o f centrat ion 3.6 .6 .4 rincipal oint o f utocol l imation 3.6 .6 .5 rism ffect 3.6.7 elative llumination 3.6.7.1 ignetting 3.6.7.2 o s4

aw 3.6.7.2.1 l luminance istribution

3.6.7.22 ariation of c o s4 aw 3.6.7.3 ea m ect ions

3.6.7.4 bliquity ngles 3.6.8 ransmittance 3.6.8.1 o l or contribution 8.6.9 pherica l berration 3.6.9.1 o c a l hift 3.6.9.1.1 3.6.9.12 aze posit ion 8 .6 .10 eiling lare 3.6 .11 ondenser

3.7 3.7.1 e rf ormance designation 3.7.1.1 c h r o m a t •

3.7.12 nastigmat 3.7.1.3 p o c h r o m a t 8.7.2 eflection educing coatings 8.7.3 nvironmental ange 8.7.4 ptical lass 3-7.4.1 efractive ndex 8.7.4.2 ispersion 3.7.42-1 ispersive ower 8.7.4.22 bb e number 8.7.4.3 ouble efract ion 8.7.4.4 hemic a l durabili ty of glass 8.7.5 nternal urfaces

3.8 BEAUTY D E F E C T S

3.8.1

aterial efects 3£.1.1 ubbles 8.8.1.1.1 Seeds 3.8.1.12 Air ells 3.8.12 racks 3.8.1.3 eathers 3.8.1.4 olds, o r laps

Position of greatest conce n tra t i on ** ...— 15

15

characteristics

MISCELLANEOUS"FEATURES \\ .

5 5 5 6 6 6 6 6 6 6 6 6 6 6 7 7 7 7 7 7 7

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MII-STD-150A 12 M ay 95 9

3.8.1.5 3.8.1.6 3.8.1.7 3.8.1.8 3.8.1.8.1 3.8.1.8.2 8.8.2 3.8.2.1 3.8.2.2 3.8.2.2 3.8.2.8.1 8.8.2.4 8.8.2.5 3.8.2.6 8.8.2.6.1

3.8.2.7 3.8.2.8 3.8.2.9 8.8.2.10 3.8.2.11 3.8.2.12 3.8.2.18 8.8.2.14

Pag*

.... 7

.... 7 .... 17

"» llKlRyffS tiHM«.ll»»»MM»»MMW»»M««l»»t»HMtH»«»»HW«*»W»»» » *l«»l«*»»MIWM, ilW i»MI»M»*»M»»W»»

Owi «klU ». • »»»• »»^•••»», ..» _•••• •• »»•*•••••••••• ♦ »•*•*•••»•••••*•*••*•••••••••"•*•••••••••**•••**•»••••••••••1

Striae 7 Rea ms — ..~......~.. 7 C ords ..~ 7 Ma nufa c tur ing efects . 7

. 7 7 7 7 7

._ 7 7

.. 7

7 7

starts

Blisters Burns Cement Run-ins .. Chips Cracks Bigs Dirt ho les

Dirt - Grayness Mold mar ks 17 Orange ee l .. . P o o r polish Scrat che s Smears , scum, water spots, etcStain

17 17 18 18 18

4.1 4.1.1 4.1.2 4.1.3 4.1.8.3 4.1.4 4.1.4.1 4.1.4.2 4.1.4.3 4.1.4.4 4.1.5 4.1.5.S

5.

5.1 5.1.1 5.1.1.1 5.1.1.2 5.1.1.3 5.1.1.4

GENERAL R E Q U I R E M E N T S 8

M A R K I N G S 8 L e n s markings 8 Cell marking 8 Maximum aperture 8 f-numb«r 8 Iris diaphragm contro l marking 8 Full to p 8

Maximum perture alue 8 Fract ional to p values 8

Tolerance of marking 9

Foca l length 9

Accura cy of focusing scales 9

DETAIL R E Q U I R E M E N T S 9

M E T H O D S O F T E S T AND MEASUREMENT 9

Test pparatus 9

Collimator 9

Optical ench nd no d a l lide d

Infinity 0

W h i t e light 0

VI

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MIUSTD-150A 12 M ay 959

Pag«

6.1.1.4.1 5.1.1.5 5.L1.6 5.1.L7

5.1.1.7.1 5.1.1.7.2 5.1.1.7.3 5.12 5X2.1 5.122 5.122.1 5.122.1.1 5.1222 5.12.3 6.1.2.4 5.12.5

5.12.6 5.1.2.7 5.12.8 5.12.9 5.1.2.9.1 5.12.92 5.12.10 5.12.10.1 5.12.102 5.L2.11 5.12.11.1 5.12:112

5.12.112 5.15.11.4 5.12.11.4.1 5.1.2.11.4.2 5.12.11.4.3 5.12.11.4.4 5.1.2.1L4.5 5.12.12 5.12.12.1 5.12.12.1.1 5.12.12.1.2 5.12.122

5.12.122 5.12.12.4 6.1.2.18 5.1.2.18.1 5.1.2.132 5.1.2.14

•••»•••»»»» »» 20

20

20

20

21

Flash discharge amps Photographic plates and ilm ... .~.

Test onditions

Resolving power arget ....... High ontrast arget Medium ontrast target 1 Low ontrast arget 1 Test methods 1

Plane of best definition _ 1 Equivalent ocal ength 1 Method — Photographic method 1

Method A — Combination method 2

Method —Nodal slide method 2 Calibrated focal length 2 Back ocal distance 2

Flange ocal distance 2

Front ocal distance

2 Front vertex back focal distance — 3 Aperture atio 3 Effective aperture ..~.............. 3 Method 3 — Microscope method 3 Method 4 — Point source method 3

T-number and ransmittance ..~_.. 4

Method — Extended ource method - » 4

Method — Collimator m e t h o d " 4 Relative llumination ....... .. 5

Method 7 — Extended source method 5 Method — Collimator method . 5

Method — Densitometric method 5 Method 0 — Indirect omputation method 6 Distortionless lens with object at nfinity 6

Distortionless lens with finite object distance 6

Distorting ens with object at infinity 6 - Distorting lens with finite object distance 6

Monocentric ens 7

Resolving ower 7

Photographic resolving power 7 Method 11 — Collimator method 7

Method 12 —Target range method 8 Method 13 — Visual esolving power 8

Method 14 — Projected photographic resolving power 9* Method 5 — Projected visual resolving power 9 Astigmatism and urvature of ield 9

Method 6 — Resolving power target method 9

Meth-d 17 — Nodal lide method 0

C o l o r orrt.tion 0

vi i

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MIL-STD-150A 12 May 95*

Tagt

6.12.14.1 Longitudinal chromatic aberration6.12.14.1.1 Method 18 — Photographic method 5.1.2.14.1.2 Method 9 — Nodal slide method gl

5.1.2.14.2 Lateral hromatic berration5.1.2.14.2.1 Method 20 — Photographic method .- 5.1.2.14.2.2 Method 21 — Nodal slide method gl

5.1.2.15 agnification • l

5.1.2.15.1 araxial agnification l

5.12.15.1.1 Method 22 — Photographic method ._ l

5.1.2.15.1.2 Method 23 — Visual method l

5.1.2.152 ethod 24 — Calibrated magnification 2

5.1.2.16 istortion — 2 5.1.2.16.1 ethod 25 — Target range method 5.12.162 ethod 26 — Collimator bank method • « • • 5.12.16.3 ethod 27 — Single collimator photographic method — 5.12.16.4 ethod 28 — Nodal slide method " " " g3

5.1216.5 Method 9 — Goniometer method ^5.12.16.6 ethod 0 — Projection method - " 5.12.16.7 angential istortion . . . ."„Z 4 5.12.17 rism ffect 4 5.1.2.18 pherical aberration — • - ; • • - " " V ~ 4 5.12.18.1 ethod 1 — Annular ring o r Hartmann isk method 5.12.182 ethod 2 — Stopped-aperture method "ZZ1 5 5.12.19 eiling glare " 35 5.1.2.19.1 ethod S3 — Photographic black po t method 6

5.1.2.19.2 ethod 34 — Photographic black trip method • 6 5.1.2.19.3 ethod 35 — Photoelectric method * * ' * 7

5.12.20 ondenser performance Z"~.. 7 5.1.2.21 eauty defects -... • •

7

5.12.22 entration 38

APPENDIX

10 REFERENCE MATERIAL38

10.1 ENERAL 10 2 EN S MOUNTING, AND OTHER REQUIREMENTS ® > 10.3 RDERING D A T A REFERENCE LIST

38 10.4 EFERENCES

38 INDEX

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Figure

1 stigmatic Difference

2 ongitudinal Chromatic Aberration

3 ateral Chromatic Aberration 4 istortion

5 elative llumination

6 pherical Aberration

7 tandard Resolving Power Test Target Element

8 rojected Resolving Power Test Plate MIUSTD-150A 12 May 959

FIGURES Paff*

._ 10

10

10

11

12

14

2 1

2 9

TABLES Table 0

I Numerical Apertures and Their Corresponding f-numbers _ «J

II Photosensitive Materials auu ^«-^ **

IX

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MIL-STD-150A 12 May 959

1. COPE

11 PURPOSE. This standard is issued or

the urpose f stablishing niform efinitions, nomenclature, lassification of defects,

methods f esting, nd measurements er- taining o he ield f hotographic enses. An appendix, ontaining nonmandatory eference material, s rovided or se n he preparation f pecifications nd ther pro-

curement documents.

1. 2 LASSIFICATION. his tandard covers hotographic enses yped ccording to their use. The eywords are italicized or convenient reference.

I erial econnaissance. ype lens hall e uitable or se n aerial econnaissance. t will e

used t r ear nfinity ocus nd usually will have lo w distortion and

a lat ield.

II erial apping. ype I ens shall be suitable for u se in accurate aerial mapping. t will e sed t or ear nfinity ocus nd sually will have a flat field. The distortion characteristics n this type f ens are sually esignated nd on - trolled within precise limits.

III eneral hotographic. ype II lens hall e uitable or se n view amera nd and-held till cameras. t will e sed o hotograph oth ear nd istant b-

jects.

IV rocess. ype V ens hall e

suitable or se n hotolithogra- phy, rocess work, nd recise e- production rom lat opy. t il l

be sed t or near unity magnification. n his ype f ens, ateral and ongitudinal hromatic berration, econdary pectrum, nd

distortion re orrected o igh

degree.

V otion Picture amera . A ype V

lens hall e uitable or se n motion icture ameras. t will e

used o hotograph oth ear nd distant objects. A type ens differs from a type III lens n hat t usually s f horter ocal ength and maller ield of view.

VI nlarger. A ype VI ens hall e

suitable for u se in photographic en- largers. t ill e sed t inite magnifications, il l sually ave lo w olor berrations, nd n ertain pplications distortion harac-

teristics will be designated and controlled within precise limits.

VII rojection. A type VII lens shall be suitable for use as an objective lens in otion icture, ilm trip, opaque, lide, nd verhead rojectors. t will e sed t inite magnification nd will ave iat field. This type f lens sually differs rom type VI lens n hat t is aster, overs maller ield f view, nd as ess orrection f aberrations.

VIII hotomicrographic. ype III lens hall e uitable or se n photomicrography. t will e sed with the bject at the horter on-

jugate.

IX ortrait. ype X ens hall e

suitable or se n ortrait hotography. t will e sed o hoto-

graph oth ear nd istant b- jects. t usually differs rom a type III lens in aving less correction of aberrations.

X Viewfinder, A ype ens hall e

suitable for use in iewfinders.

X I ondenser. A ype I ens hall e

suitable or se n ondensers. t

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MIL-STO-150A 12 May 9S9

will e sed or he ollection nd distribution f radiation n rojec-

tion and nlarging: systems

XII opying. A ype XII ens hall e

suitable or se n eproduction from lat copy. It will be sed at or near unity magnification. It usually differs from a type V lens n hat it as reater ens peed nd ess correction f berrations.

XIII Microphotographic. A type XIII

r

lens hall e uitable or se n

microfilming nd microcopying. t

usually will e sed t magnifica-

tions between 0. 1 nd .024.

XIV ecording. ype XIV ens hall be suitable or use n recording instruments r luorescent creen

presentation. t ill e se d t finite magnification nd enerally will e f pecial design o meet

the specific requirements.

2. REFERENCED D O C UM ENTS

2 .1 NOT APPLICABLE.

3. DEFINITIONS

3. 1 A X E S , POINTS, AN D DISTANCES.

3.1.1 ptical axis. The ptical xis f perfect lens or ens ombination is that continuous traight ine n pace which asses through ll f he enters f urvature f the arious pherical ptical urfaces, oin-

cides with, the xes f otational ymmetry of nonspherical surfaces and is perpendicular

to la t urfaces.

3.1.2 Axis of best efinition. The xis f

best definition f a lens s that line n which is erpendicular o he lane f est efinition nd asses hrough he rincipal ocus.

3.1.2.1 lane of best definition. The lane of est definition s that lane in he mage

space hich ontains hose mages epresenting ompromise f uality elected s

best or he urpose or which he ens s

intended.

2J . .2 .1JI lane f est vrragt definition over he picture area. The osition f ocus

giving he ighest rea weighted verage resolution AWAK) il l e irst onsidered as he osition f est verage efinition

over he icture area, r BADOPA. n ase the esolving ower or he xial mage point is less than the AW AR , the .position of focus t which he xial esolving ower equals he W A R will e onsidered he

position f B A D O P A .

3.1.2 .1 .2 Field tut. A lens field tilt when its best mage plane s tilted with respect to the mounting houlder or he ens . This ffect is sually aused y light mounts f e- centering r ilt n r within member f an ptical system. Field tilt results n lack of ymmetry of resolution in the field f the lens bout he xis. Usually he oints f greatest symmetry ie long diagonal f

the icture ormat. The imits or ield ilt may be specified n terms of maximum focus

difference etween he two ositions of best focus at a specified angle during the diagonal

exhibiting he reatest symmetry.

3 .1 .2 . 2 Best principal focus. The best prin-

cipal focus of a ens s the point of intersec- tion f he ens xis with he lane f est definition rom an ncident beam f arallel

light erpendicular o his plane.

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3.1J2-2.1 W h e n ens s upplied n ells, with ou t arrel r hutter, h e ocat ing urface of th e lens m o u n t is defined as the seat-

in g surface of the rear cell.

3.1.3 Mechanical axis. T h e mechanica l axis

o f lens s that ont inuous traight line n space perpendicular to th e plane of th e flange o r ocat ing urface f he ens m o u n t nd passing t h rou gh the enter of symmetry of

th e flange r locating surface.

3.0.1 Flange tilt. T h e flange tilt of a lens is the angle between the opt ica l axis and the

mechanica l axis.

3.1.3.2 Plane of the receiver. T h e plane o f th e receiver is that plane in the image space in w h i c h the receiver o r the film in a camera is located.

3.1^2.1 ocal ut. h e o c a l ilt s he angle etween h e lane f est efinition and the plane of th e receiver due to the m e- chanica l tructure etween h e ens lange an d th e receiver. It is not a true characteris-

tic of th e lens alone.

3.1.4 Equivalent focal length} T h e equivalent o ca l ength , r EFL. ften eferred o mor e imply as th e focal ength, etermines th e scale of h e image roduced by th e lens. W h e n a given object is at an infinite distance, images roduced y istortionless enses of th e same equivalent f o c a l length will be equal in size, and images produced by lenses of different quivalent o c a l engths will vary n size irectly s h e espective quivalent f o c a l engths. h e quivalent f o ca l ength s

defined by the equation: T

EFL ta n ß

/ » - ° (1)

M I L- STO- 150 A 12 M ay 95 ?

where T is th e transverse distance from th e principal focus to th e center of the image in the mage-space ocal lane of an nfinitely distant object point w h i c h lies in a direction making an angle ß with the optical axis. T h e equivalent f o ca l ength hal l be measured n

a cco r da n ce with 5.1.2.2.

3.1.5 alibrated focal ength* h e alibrated f o ca l length, o r C FL , is denned as an adjusted value of the equivalent f o ca l length of ens mounted n amera r one , o c h osen as o distribute th e istortion in h e manner best suited to condi t ions under w h i c h the p h o tograp h s to e employed. T h e alibrated ocal ength hal l e etermined n ac c ordanc e with 5.1.2.3. T h e cal ibration c on-

ditions ha l l be covered y he detailed specification.

3.1.6 Back ocal distance. T h e ac k focal distance, r BF, s efined as he istance measured rom the vertex of the back urface of the lens to the plane of best definition. The back f o c a l distance shal l be measured in ac c ordanc e with 5.1.2.4.

3.1.7 Flange focal distance. T h e flange focal

distance, r FD, s efined as the min imum distance from the center of symmetry of the lens lange n he plane o f he lan« to th e plane of best definition. In a perfect lens, this distance s easured l ong he echanica l axis h i ch o inc ides with h e axis of best definit ion. T h e flange oc a l istance sha l l be measured in a cco r da n ce with 5.1.2.5.

3.1.8 Front focal distance.9 T h e front f o ca l

distance, r F, s efined s h e istance

measured ro m h e rincipal ocus ocated in the ront space to h e ertex of the front surface. h e ront o c a l istance ha l l e measured n c co r da n ce with 5.1.2.6 .

3.1.9 Front vertex back focal ditUmct.1 T h e

For.l Unrlh« »nd roMl DiiUnc« of rholofrmpfcle

7M> 1 > < > < «

> M ootnvu 1. ««» •

• *> foot*«*» 1. P*»»

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MIL-STD-150A 12 May 959 front vertex back ocal distance, or FVD, s

defined s he distance measured rom he principal focus in the back space to the vertex f he ront urface. The ront ertex back focal distance shall be measured n c-

cordance with .1 .2 .7 .

3.1.10 Telephoto atio. The telephoto ratio is defined as the direct ratio of the equivalent focal ength o he ront ertex ac k ocal

distance.

3.1.11 Depth of ocus and depth of ield.

For every plane in the object space, a photographic lens produces an image plane of best definition n the mage space. In front of or

behind this plane of best definition is a region within which he mages f the selected b- ject lane re f atisfactory uality. he distance eparating he ocal lanes ond- ing this region is the depth of focus for the selected object plane. Similarly, there exists a egion n pace within which bjects re imaged with satisfactory quality on a selected image plane. The distance separating he planes ounding his egion s the depth f field. The extent of these regions of satisfactory ocus may e efined n erms of a 0

percent eduction f area weighted verage resolution AWAR) elow hat obtained t the best focal position.

3.2 APERTURE AN D RELATED Q U A N -

TITIES.

3.2 .1 Lens peed. Lens peed s that property f ens which ffects he mage l- luminance. Lens peed hall e pecified n terms of the following expressions: aperture

ratio, relative aperture, or T-stop.

3.2 .2 Aperture atio* he perture atio is the atio :N r the raction /N written n this manner with the irst member of

the atio, r he umerator f the fraction,

r

' AJBtni»n Sundird Mrthod» of Pwlf-nttini «n<j M»*»urtm

Ar»rtu«« mn d Rrl»Ud Qu»ntilW« P«rt»Jr«inr te Pbot»rr»phlc

Lan*«. 7.SS .IO - 1 * * «

equal o ) where N s denned b y the equa-

tion: 1

N

2n in a

In his formula, n s he index of refraction of the medium in which the image is formed (approximately 1, if the image s formed n the air) nd a is the ngle subtended at the axial point of the image by the semidiameter of he xit upil f the lens at a iven diaphragm etting. f the xit pupil s ot circular, he quivalent ircle having the same area as the actual exit pupil hould be used. Thus, or n bjective n ir, he perture ratio is equal to 2 sin a. If the aperture ratio

is iven without ualification, ts alue s that orresponding o he argest ndicated diaphragm opening and n infinitely distant object. If the object is at a finite distance, the value of the aperture ratio should be qualified by a statement of the corresponding magnifi-

cation. The perture atio s pplicable or the etermination f xposure ime when the bject s t n nfinite r inite istance. or ny magnification, he xposure time s nversely proportional to the quare of N . Thus, he perture atio s a measure of the image illuminance. For test procedure

see 5.1.2.8).

3.2 .3 ffective perture* he ffective aperture f hotographic bjective or distant bjects, or iven etting f he diaphragm, s n pening quivalent o right section of the largest beam of parallel light from an axial object point that is transmitted by the lens. t s sually ircular, or approximately so, and s specified by its dia-

meter. If the section is not circular, the effec-

tive diameter shall be the diameter of a circle having he ame quivalent rea. For est procedure, se e .1 .2 .9 . )

3 .2 .4 lear aperture.' The lear perture of each urface in a lens system s the roaxi-

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m um lear pening of the urface which s actually se d n orming n mage n ny part of the field. T h e m o u n t aperture at each surface shal l be at least as large as the clear aperture n rder hat ignetting will o t exceed h e omputed alue. h e lear perture s sually ircular nd pecified y ts diameter. It is somet imes referred o as th e free aperture.

3JJ.5 Relative aperture.1 T h e relative aper-

ture shal l be denned as th e ratio of the EFL

to th e diameter of th e effective aperture. T h e symbol or elative perture ha l l e f fo l l owed by a numerica l value. t s written as a fraction, for example, f/2 signifies that th e diameter o f th e effective aperture is one- half h e o ca l ength . o r n bject at n infinite distance, the denominator of the relative aperture and the second member , N, of th e aperture ratio are identical, provided th e image is formed in air and th e imagery obeys th e sine condit ion.

S.2.5.1 -«uwdcr.« h e -number ha l l e defined as the denominator in th e expression fo r h e relative perture. hus , f he elative aperture is f/2, th e f-number is 2.

3.2.6 T-stop and T-number. ' T h e T-*top is

referred o s h e perture f ens alibrated hotometr ica l ly nd ssigned - number, w h i c h is the f-number of a circular opening n a fictitious lens having 00 er - cent transmittance, and w h i c h gives th e same central mage i l luminance as th e ac tual en s at h e specified top pening. H enc e , or lens with a circular aperture, the

T-number f-number

V t (3 )

wher e t is th e traasmittanoe. Fo r a lens with an effective perture o f ny ha pe nd rea

• 8* oo tnoU , •(• . ' AJMrtnn u a dwd, Apvturi allbralioD f Motion lcturt

ran » o —19«.

M 1 L-S TD -1 50A 12 M ay 95 9

A , the corresponding f ormula is:

f T-number V ^ (4)

T h e transmit tance of th e lens shal l be defined

as h e ratio of h e transmitted ight flux to th e nc ident ight lux. h e ym b ol or h e T-stop shal l e T fo l l owed y a space and a numerica l alue — o r xample, . h e numeral epresents h e -number. For test procedure, ee .1.2.10.)

3.2 .6.1 Area weighted average T-number. T h e -number as efined n .2.6 s a o m - parative measure of i l luminance n h e axis of a lens. Since th e i l luminance usually varies

over th e field, a need m ay exist for determining T -n umbers for off-axial image points and c omp u t ing an verage T-number . In c c ord - ance it h he asic hotometr ic elation- ships nvolved, h e eneral efinition of ni-mber s given s

T , U 5rB/E t

Since , in ac c ordanc e ith this definition, 1

2 — yj B T.-y E„

(6)

In hese expressions, T t s th e T-number fo r an ma ge point n o ne , « s h e xial T-number, B s h e bject uminance , E 0 s the l luminance n h e axis, nd i s h e average i l luminance fo r th e zone. Compatible units hould e sed or uantities , „, and ,. h en h e l luminance s veraged over h e field, weighting h e average by h e area o f th e circular zone in w h i c h the i l lumi- nanc e is determined, and this average is sub-stituted fo r EL .in.equation 6), th e resultingT-number s alled h e rea weighted ver-age T-number, o r A W A T . Fo r circular zonesw h i c h xtend evond he oundaries of h e

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MH-STD-150A 12 May 9S 9 picture format, only th e area lying within th e format hall e sed n etermining h e weighting ratios. T h e equations fo r comput- in g A W AT are:

A W A T -N> "ÄTET

AE,

or A W A T 10 T ^ / V H (7 ) (8 )

in which A s h e total rea of th e icture format, Ai s th e area o f a .particular zone, an d o t is th e average relative illuminance fo r that zone expressed in percent

3*2.7 Front operating aperture. T h e front operating aperture is defined as th e limiting aperture at th e front o f th e lens. It will usually be given as th e maximum diameter o f th e entrance cone at th e front vertex fo r th e specified field o f view at infinity focus.

3.2.8 ear perating perture. T h e ea r operating aperture is defined as th e limiting aperture at th e rear of th e lens. It will usually be given as th e maximum diameter o f th e emergent cone at th e rear vertex fo r th e spe-

cified field o f view at infinity focus.

3.3 CONSTRUCTIONAL FEATURES. Pertinent features include details o f th e con- struction o f th e lens. These m ay relate to th e physical onfiguration, r rrangement f th e ndividual lements, o om e pecified optical characteristic o r to th e nomenclature o f th e various parts. Constructional features of photographic lenses are listed with definitions an d explanatory data.

3.3.1 Optical ystem* T h e ptical ystem includes al l th e parts o f a photographic lens an d ccessory ptical arts which re e- signed to contribute to h e ormation o f an image en th e photographic emulsion o r on a screen fo r viewing.

3 2 ember* member f hotographic lens s a roup f parts considered as an entity because o f th e proximity o f it s parts o r because it h as a distinct bu t no t always entirely eparate function.

3.3.3 Component* A component o f a photographic lens is a subdivision of a member. It m ay consist o f wo r more parts emented together r ith ea r nd pproximately matching surfaces.

3.3.4 lement* n lement f hotographic lens s a single uncompounded lens, Le^ a part constructed o f a single piece. T h e total number of elements is a significant constructional feature o f a lens.

3-3^ ront f hotographic ens.* h e front f a hotographic ens, n eneral, s th e end carrying th e engraving, an d usually facing h e onger onjugate. n en s rawings, th e f ront generally faces left or up. A notable xception s ertain enses intended to be used in photomicrography in which th e front of th e lens faces th e shorter conjugate.

3.3.6 Back of photographic lens* Th e back

o f a photographic lens, in general, is th e end carrying h e mounting hread r ther t- taching means and usually facing th e shorter conjugate.

3.3.7 Name of design. Designs o f lenses in which articular onfigurations f elements are employed re ften iven ames. hese names are usually trade names, and th e name ordinarily applied to any particular configu- ration is usually th e trade name o f th e oldest

design f articular yp e uc h s Tes- sar." n o m e ases, owever, h e esign name m ay no t be a rade name ut m ay e based n o me feature o f th e lens configura- tion such as ••Symmetrical.'*

3.3.8 Telephoto. A telephoto lens is defined

r

•

prmufc lc Laal Steadard Kama FBI.»— IMt,

idatan fo r Part* o f » Photo- • merican Standort Nomon eUtur» fo r ParU of a P K o U - rriphtc Un« PH 3 J 1M B

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as ens or hich he elephoto atio s

greater than one, S ee 8.1.10.)

ZZ3 Glass types. A constructional feature is he ype f ptical lass f which ach

element is made.

3. 4 MECHANICAL AND T R U C T U R A L

F E A T U R E S .

3.4.1 ell. A cell is a mechanical structure holding an lement, omponent, r member.

3.4.2 Barrel. A barrel is a mechanical structure in which the lens is mounted.

3.4.3 one. A one s enned s he mechanical tructure to which a ens barrel or shutter, with ens, s ttached n rder o bring the image in focus in the film plane of a specific erial camera.

3.4.4 en s iaphragm. A ens iaphragm is mechanical evice or educing he f- fective perture f ens. t may take he form of an iris or a Waterhouse stop. An iris diaphragm onsist f eaves roviding n opening continuously variable in size. A W a- terhouse stop is a removable aperture of fix-

ed size which fits n he lens barrel. Water- house stops are usually provided in a graded series of pertures.

3.4.5 Iris diaphragm control.* Unless otherwise pecified, when ooking at the front of a ens r emote ontrol nob, ounter- clockwise otation of the diaphragm ontrol shall educe he perture r top he ens

down.

3.4.6 P a r focalized. Lenses mounted in barrels may be specified as parfocalized, i.e., th e flange focal distance m ay be specified to close tolerances hat would ecure n mage n satisfactory focus when the lenses are inter-

changed on a camera,

• An»Hnn r1tl«h-Can»<JUn ir tand» niliatlon rrtanwnt.

A ir amtn * n» »»f*f»fm atatkm nd *n* fw«d Mm

Sr»t»m. BC IR T D t/t. rt »« .

MII-STD-150A 12 May 959

3.4.7 Spanner wrench penings. When e- quired in order to facilitate removal of cells, elements, omponents, r members rom cell r arrel, here hall e wo penings 18 0 degrees apart for application of a spanner wrench. ac h pening hall ither e

circular n

hape,

r lo t with

arallel sides.

&5 FI E L D O F V I E W . T he field of view of a lens s measure of the size of the image area or conjugate object area which is satis^ factorily eproduced. his ield may e e- fined n erms of he maximum iz e f he negative r rojection material with which the lens is to be used." The angular measure for field of view is th e half angle, which, unless otherwise specified, is the angle subtended at the first nodal point by th e optical axis and a straight line to an object point which is imaged at the extreme corner jof the negative. or rojected mage, he half ngle is he ngle ubtended t the second odal point by he ptical xis nd in e o he image point conjugate with the extreme corner f he rojection material. he alf angle s ometimes eferred o he id e f the mage rea nd n uch ases t hall always be so specified. T he field of view m ay

also e esignated s he otal ield ngle which s twice the half angle. overage s a less precise term for field of view.

3.6 PTICAL CHARACTERISTICS. ptical characteristics include all properties of a lens ffecting ts ptical erformances uch as mage uality, istortion, ransmittance, image olor; nd ondenser haracteristics. W hen pecifying ptical haracteristics r individual berrations, he efinitions nd

nomenclature set forth herein shall be used.

3.6 J L Image quality. Image quality embrac-

- Fotmat l^Tlor Air *xt»r%». BC A IR T D J/1. ab . M T h « articipant» **** «* l lr *">«*» ormat ts« hal l

U: W bJ K »<*«, % " W T"*W' *T

"rS" * " tnehaa. I r » n«*»«. Sorwat * * • • «* remnA OMMIM,

A BC IR T D t/*, i > r. . roond antn ormt ta» aUuM lani» « ball . 1 k7 1% » • • » « * • • (2 « y S« mil»at«T.>.

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MII -STO-150A 12 May 95 9 es ll he properties f lens ffecting he quality of th e image such as resolving power, aberrations, image defects, an d veiling glare. Aberrations re ptical efects nherent n the ens esign. ecause f manufacturing

variations, t ften appens hat he measured berrations iffer ro m he omputed aberrations. mage efects re ptical e- fects not inherent in the lens design an d re - sulting ntirely rom manufacturing nd mounting ariations. his tandard s rimarily concerned with ptical performance. Optical erformance an e easured n terms of resolving power, or specific optical

characteristics.

3.6.2 Revolving power. T he resolving power of a lens is a measure of its ability to image closely spaced objects so that they are recog- nizable s individual bjects. he esolving power hall be expressed n lines per millimeter, usually in the short conjugate plane. Resolving power is measured b y photograph- ing or observing suitable test charts at specified ngular, istances rom he enter f the ield. he est harts hall onsist f groups of parallel traight lines an d paces

of equal width; he esolving power s he reciprocal f he enter-to-center istance of th e lines that re just distinguishable n the ecorded mage. y just istinguish- abh" s meant that the observer s able too count the correct nu mbe r of lines in the re - corded mage, over the ntire length f the lines and in the orrect orientation, ubject to the provision that n o coarser pattern shall b e unresolved. T he appearance of resolution in a finer pattern after failure to esolve a

coarser pattern is an indication of the presence of spurious resolution. Spurious resolution s a phenomenon wherein fine lines are resolved, yet coarse ines re ot For non- axial oint«, it is ecessary to consider he orientation of he tn«. or xample , he resolving power for adial ines, r "radial resolving power" sometimes called "sagittal revolving ower*

,), t a iven oint n he

rimage plane is th e resolving power for closely spaced lines that are parallel an d adjacent to the radius drawn rom the enter of the field to the given point Resolving power for tangential ines, r tangential esolving

power," s he esolving ower or losely spaced parallel lines that arc tangent an d ad - jacent to ircle drawn hrough he given point whose enter lies t th e enter of the field. esolving ower may e pecified s minimum cceptable esolving ower, e- gardless f whether adial r tangential t specified angles from the optical xis of th e lens, or it may be specified at both minimum acceptable adial nd inimum cceptable tangential resolving power at specified angu-

lar distances from the optical axis. T he average esolving ower weighted n erms f the area of the negative, the area weighted average esolution A W A R), rovides single value y which he esolving ower for he ntire ield m ay be pecified. S ee 3.1.2.1.1 an d 8.65.5.)

3.6 .2 .1 hotoffraphie uolving ower. Photographic esolving ower s se d n specifying nd measuring erformance f type I, n, m, IV , V, IX , XII, and Xm lenses

an d is the greatest number of lines per millimeter recorded photographically as separate lines. A target pattern is considered resolved when t meets he onditions escribed n 3.6 .2 . Photographic resolving power depends markedly n he hotographic onditions employed, nd n he resence f ackground lare rom he Dmninated arget When pecifying hotographic esolving power, t s ecessary lso o pecify he color of light to be sed, the type of photo-

sensitive material nd rocessing, he ens speed at which the tort is made, the contrast of the target and the magnification or focus at whlch-the lens s ests«. S ee 5X2.12 .1)

3£JU mtaX t—cAvUg power. Visual resolving ower s sed n pecifying nd measuring of ype enses, nd s efined as he reatest u mbe r f ines er O U *

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meter n he mage f est arget attern that are just barely distinguishable as eparate ines nder dequate agnification.

When specifying visual resolving power it is necessary also to specify the arget contrast (See .1 .2 .12 .2 . )

3 .6 .2 .3 rojected hotographic esolving

power. rojected hotographic esolving power s sed n pecifying nd measuring the erformance f ype VI enses nd s defined s tne reatest umber f ines er millimeter, in the object plane, that are barely istinguishable s eparate ines when observing nder agnification hotographically ecorded, rojected mage f suitable est arget. S ee .1 .2 .12 .3 .) When

specifying rojected hotographic esolving power t s ecessary ls o o pecify ens speed, focus, magnification, type of illumination, ontrast f target, ype hotosensitive material nd ts processing.

3 .6 .2 .4 rojected isual esolving ower. Projected isual esolving power s sed n specifying nd measuring he erformance

i of ype VII enses nd s efined s he I greatest umber f ines er millimeter n

the bject lane hat are distinguishable s separate lines in he projected image. When specifying projected isual esolving power, it is usually understood to imply a high ontrast arget dark ines n ight ackground). See 5.1 .2 .12 .4 . )

3 . 6 . 2 . 5 Area weighted average esolution. A ingle verage alue or he esolution over he picture ormat may be determined

for any given focal plane as the area weighted verage esolution, r AW AR . o determine he WAR, he icture ormat s divided nto concentric nnular ones whose

boundaries re etermined rom he ngles which re midway etween uccessive est angles. For ones which xtend eyond he boundaries f he icture ormat, nly he area ying within he ormat hall e sed

in determining the weighting ratio. The reso-

MIL-STD-150A12 M ay 959

lution btained t ny iven est ngle smultiplied y he atio f he rea f hezone or hat angle o he total rea f thepicture ormat. he AWAR s he um fthese roducts. o btain ingle alue fthe esolution or ach est ngle, he eo-

metric mean f he angential nd adiaresolutions shall be used. However, the com

putations may be simplified by the use of anarithmetic mean henever he angentiaand adial esolutions differ y ess han factor of 2 o . When more than one measurement is made t any given test angle, anarithmetic mean shall be determined for thetangential nd nother or the adial eso

lutions. he rea weighted verage esolu

tion s defined s:

AWAR _ A * 9where A, s the area of a particular zone, R

is the average radial esolving power in thizone or adial esolving power at the midpoint of the zone), T, s the average tangential esolving power in the zone or the tangential esolving ower t he idpoinof the one), nd A s he total rea of thpicture ormat, nd s he ummatio

sign, ummating the values

A,

V R. ,

over all zones in the picture area.

3 .6 .3 Astigmatism and urvature of fiel

In eneral, ens ossesses wo mage sufaces: on e in which lines radial to the opticaxis re best defined and the other n whiclines angent o ircles oncentric with thaxis re est efined. oncoincidence these wo mage urfaces s alled stimatism, and the separation of the two imagsurfaces, measured arallel o h« ptic

axis, s alled he stigmatic ifference.

median surface lying between the two is ca

ed the surface of least confusion and the de

nition in his image surface s east ffect

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MIUSTO-150A 12 May 959 by orientation o f th e object. None o f th e surface» s ru e lane. h e eparture o f h e surface of least confusion from a true plane is called curvature o f field. Resolving power figures, pecified n ccordance with .6.2,

will sually e onsidered s referring to flat image an d object plane. W h e n curvature o f ield s pecified, h e agnification t which t s o be measured hall e tated (See 6.1.2.13.) Figure is plotted s an example o f th e astigmatic difference.

AN6UL*r ISTANCE RO M AXIS

Picon; . Astigmatic Difference

3.6.4 Color correction. Color correction s defined as th e reduction of longitudinal an d lateral hromatic berrations. t ay e specified n erms f th e ind f ight an d color ensitivity f th e hotographic mate-

rial to be used with th e lens, ex, th e lens is color corrected fo r use with white light an d panchromatic ilm of A SA peed 00. h e color correction m ay be specified in terms o f th e Fraunhofer ines n h e olar pectrum that are o be used n h e lens calculations, e.g., C an d F orrection. h e magnification at which th e co lor correction is accomplished shall be esignated. See .1.2.14.)

3.&4.1 Longitudinal chromatic aberration.

Longitudinal chromat ic aberration is defined as a variation in back focal distance fo r light o f ifferent olors r wave engths. t s specified n erms f h is ocal hange o r H g f c t f pecified olors. See .1114.1.) Figure 2 U plotted s «a xample of longitudinal chromat ic aberration,

& . 6 . 4 L 2 Lateral chromatic aberration, Late-

FOCAL CHANGE (r\n)

FIGURE . Longitudinal Chromatic Aberration

ra l hromatic berration s ariation n image cale f a en s o r ight/ o f ifferent co lors r ave engths. h en equired, limits n ateral hromatic berration il l be pecified s h e adial isplacement n

millimeters of h e mage n h e irst olor from h e mage f h e am e oint n h e second olor. See .1.2.14.2.) igure s plotted s n xample of ateral hromatic aberration.

*jy-

r o 4

ft

"30 S O 0 0 O " K O 653 T* WAVl fHSTH Of LIGHT (HI?)

Ficmx . ateral hromatic Aberration

3.6.5 Magnification.

3.6.5.1 Paraxial magnification. T h e paraxial agnification, ften eferred o ore simply as magnification, determines th e scale of th e mage when h e bject is t a finite

distance from th e lens. h e paraxial magnification, o r PM , s defined y h e following equation:

PM limit (10)

y- where •/ is th e radial distance from th e optical axis to th e image point in th e image plane

10

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conjugate with the object plane, and y is the radial distance n he bject plane rom the optical axis to the object point. Unless otherwise pecified, he mage lane is efined s

the lane f est hotographic imagery or the xial bject point; he image lane may also e pecified s he lane f best defini-

tion. Paraxial magnification hall e measured n accordance with .1 .2.15.1.

3.6 .5 .2 Calibrated magnification. The alibrated magnification, or C M , is defined as an adjusted value of the araxial magnification of ens mounted n n nstrument. his value s o hosen s o distribute he dis-

tortion in the manner best suited to the conditions nder which he ens s o e m- ployed. The calibrated magnification shall e determined n ccordance with .1 .2 .15.2 .

The alibration onditions hall e overed by the detailed specification.

3 . 6 . 6 Distortion. These re wo inds f distortion—radial and angential. When distortion s eferred o without esignation, radial istortion s mplied. n om e n-

stances, t may e esirable o pecify he distortion n erms f artesian oordinates rather than polar coordinates. Because of the wider usage f the polar method f pecifying distortion, adial nd anjrential istortion nly re enned n his tandard. This does ot reclude he necification f istortion n artesian oordinates. mall an- do m istortions hrough he ield mav e

introduced y nhomojreneities n he lass

and rreeularities n he urface f he le - ments. Figure s plotted s n xample f distortion.

3.6 .6 .1 adial distortion. Radial distortion is adial isplacement f mage oints from he ndistorted osition, omputed n

the asis f he quivalent ocal enpth r

calibrated ocal ength when he bject is t

ininnity. r n he asis f araxial magnification or calibrated magnification when the

1*+

10-•

>E , 05 r r ° UJ

*1 5 OS

to A N 6 U LA K ISTANCE FF XIS

FiCURE . Distortion

object s t inite distance rom he ens.

When adial istortion s resent, traight lines in the object space not passing through the ptical xis re eproduced s urved lines n the image. When the mage oint is displaced adially utward rom he enter of the image, the distortion is positive commonly called barrel distortion if the absolute value f he egative distortion s ontinuously increasing from the center.) When the displacement f he mage oint s oward the enter f he mage, he istortion s

negative commonly alled arrel distortion if the bsolute alue f the egative distortion s ontinuously ncreasing rom he center). The magnitude of the distortion and its olerances hall e pecified n millimeters. t may e pecified n erms f he amount at different field ngles, or by means of a urve, plotted n millimeters against the field ngle. When limits o the tolerated is - tortion re pecified, hey hall e pecified in millimeters and shall apply to any part of

the ield or which he ens s orrected. When pecifying istortion, he onditions under which he ens s sed, whether with

parallel light, copying at to or 1 to 2 , etc., shall be specified. See 5.1.2 .16.)

3 . 6 . 6 . 2 angential istortion. anpential

distortion is an mage defect resulting in the

displacement f mage oints from he n-

distorted position) erpendicular to a radius

11

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MIL-5TD-150A 12 May 959 from th e center of th e field. T he radius from which angential istortion s easured originates at th e principal point of autocollimation nd ontains he ndistorted mage

point the oint t which he image would have allen f t ad ot een distorted). When angential istortion s resent, straight lines in the object space which pass through the axis of best definition are repro- duced as curved lines in the image. Tangen- tial distortion is usually specified as a maxi- mu m permissible alue throughout the field.

(See .1.2 .16.7 .)

3.6.6.3 rrors of entration. Lenses with

spherical surfaces are usually designed to be so constructed that the enter of urvature of all the surfaces will lie on a single straight line ermed he ptical xis f the lens. f aspherical surfaces are used, their individual axes should correspond with the optical axis of the ens. ailures o omply with hese conditions re ermed rrors f entration. Errors of centration cause tangential distortion, rism ffect, ield tilt, nd asymmetric

radial istortion.

3.6 .6 .4 rincipal point of avtocoUimation. T he rincipal oint f utocollimation s term used in measuring distortion an d is defined xactly he am e s rincipal ocus, except hat he lane f est efinition s assumed o e the actual mulsion lane f th e camera. See 3.1.2.1.)

3.b.6.5 rism ffect. ens as prism effect" when light from n nfinitely distant object point passing hrough he rear nodal

point n in e erpendicular o he mage plane of a camera is not imaged at the principal oint f he erspective. he rincipal point of the perspective is the point of inter- section with the focal lane of a perpendicular dropped from the rear nodal oint of th* lens. he rincipal oint of th e erspective an d principal point of autocollimation should

coincide. Decentered enses behave as if they consisted f an deal lens plus a thin prism.

T he imits n rism ffect, when equired, shall he specified in terms of the vertex angle of he rism index 5) hich would give he am e esult se d n ombination with a perfect lens. S ee D.L2.17.)

3.6 .7 elative luminatiorL elative llumination s efined s the ratio f the illuminance at the focal lane, for off-axis field positions, o he lluminance "for he center of the field. This assumes that the luminance of the object field, as observed from the lens, is the same throughout the field, or that the field s a Lambert's law surface. T he reduction in illuminance may be doe to such causes as bsorption, osine ariations, nd barrel vignetting. elative llumination hall e specified s percent of axial Illuminance for image oints t iven angular istances. A curve on which percent of axial illuminance is lotted gainst ield ngle may e sed. For urposes f specification, the following example is given: At f/6.3 the image illuminance t 5 egrees hall be no less than percent, nd t 5 egrees no less than 2 0 percent f he mage lluminance n xis. (See 5.1.2.11.) Figure 5 s plotted as an ex-

ample of relative illumination.

r

m

f,txiULhZ ^.ilANCt FT AX 3

FICURE . elative llumination

3.6.7.1 Vignetting. Vignetting s he ro- gressive reduction in the cross-sectional area

9

1 2

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of a beam f light passing through a lens as

the bliquity f the beam s ncreased. t s

due to obstruction of the beam by the various mechanical pertures, ens ounts, tc, within he ens. The ross-section f he

beam must b e taken in a plane perpendicular to he ptical xis f he ens.) hus he beam f ight rom n xial bject oint passing hrough he ens s enerally ircular in cross-section, whereas an oblique beam

originating at any extra-axial object point is

generally on-circular n hape ue o he "*vignetting" ction f he arious imiting apertures within he ens. his estricted usage of the term "vignetting" must be carefully distinguished rom ts ommon mean-

ing, which enerally efers o he rogres- sive eduction n mage lluminance t n- creasing bliquity; he opular erm hus combines he wo distinct oncepts f rea vignetting and he os

4 ffect

3 .6 .7 .2 os* aw. When ight rom niform diffusing source falls on a plane screen parallel with he ource t distance rom it which s arge n omparison with the i-

mensions f he ource, he lluminance n the creen aries pproximately s os * t >

where is the angle between the axis of the source and he line joining the center of the source o he creen-point nder onsideration.

3 . 6 . 7 . 2 . 1 Uwninance istribution. hen illuminated y n bject f niform umi-

nance viewed rom he ens) nd f iz e

sufficient o ntirely ill he ield f iew, lens aving ircular iaphragm ives, within the mechanically unvignetted ortion

of he ield, istribution f lluminance which ollows he os* aw n erms f he obliquity ngles t he diaphragm rovided that the conditions stated below are satisfied. A ens with iaphragm n ront ives distribution f lluminance roportional o cos* where 4 , s the bliquitv ngle n he object space) f he mage s ree rom is -

tortion nd f he distance rom he bject


plane o he iaphragm s ery arge with

respect o he diameter f he iaphragm.

A ens with n nternal diaphragm ives

distribution f lluminance roportional o co s

4 i where 4 > A is the obliquity angle in the

diaphragm pace) f he omponent ehind the iaphragm oe s ot ontribute o he image istortion nd he perture s ery

small. ens with iaphragm ehind t gives istribution f lluminance roportional o os

4 ' where f > s he bliquity

angle n he mage pace) f he istance from he diaphragm o he mage lane s very arge with espect o he iameter f the diaphragm. n each case, the distribution of lluminance xactly orresponds o he

distribution hat would e btained with small ircular Lambert's aw ource laced at such a distance from he image plane that the bliquity ngles rom he enter f the source o he mage oints re s efined above.

3 .6 .7 . 2 . 2 ariation of os* a w . rdinary optical distortion n he ens will n enera? have a considerable effect on the distribution of illuminance across the field when expressed s unction f he ntering bliquity

angle . om e enses ave een onstructed in which he os ' aw as een lmost completely ullified y he resence f sufficiently large amount of barrel distortion. Regarded naively, the distortion may be said to compress the outer part of the image, thus increasing he lluminance within t.

3.6 .7 .3 Beam sections. When it is necessary to ompute he ight distribution o be nti- cipated n ew ens design, r when sti-

mating he ight istribution rom he i- mensions f ens without making ctual photometric measurement, t s ecessary to determine he ection f ight eam s t enters r eaves he ens, t dopted eference planes perpendicular » D the optical axis of the lens. onveni*»-L eference plane«; re the lanes efined y he ims f he ens

mounts t he wo nds f he ens arrel.

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M1L-STB-150A 12 May 959 A ight ea m ro m n xtra-axial bject

point, roceeding h rou gh h e en s o ts image oint , il l ntersect hese w o eference lanes n wo beam ections," ene-

rally on-circular n hape . hese ec t ions can e plotted nd h e reas measured see 6.1.2.11.4), r h ey an e omputed f he lens onstruct ion s n o w n y racing sufficient number of skew rays.

3.6.7.4 Obliquity angels. Fo r n y o int of th e eference plane n h e bject pace, s th e ngle etween orm al ro m h e ront nodal oint to th e eference plane an d a in e joining h at o int ith h e bject oint

Similarly , or n y o int n h e eference plane in th e mage pace, ' s th e angle between h e norm al ro m the rear noda l o int to th e reference plane an d a line joining that point it h h e mage oint . h e bliquity angle s h e am e o r very ay f h e entering oblique parallel beam.

3.6.8 Transmittance. Len s transmit tance is defined as th e ratio of th e light flux leaving a lens o th e ight flux ntering h e ens. t s specified s ercentage. h en pecifying

percent ransmit tance nd olerance, h e co l or of th e light incident on h e en s should be pecified, nd h e pectral ensitivity f th e film, wh en sed, hould ls o be specified. Percent transmittance m ay lso e pecified as spectral transmittance, wherein th e transmittance t each wa ve length s pecified.

3.6.8.1 olor contribution. Fo r o m e se s th e co lor o f th e light transmitted by an optical ystem s n mportant onsideration.

T h e co l or o f th e opt ical glass, coatings, interference films, and ilters sed etermine h is property. h e ffect h at h e ptical ystem

h as upon spectral haracterist ics o f th e litht flux ntering h e ystem s ermed co lor contribution." h is roperty f n ptical system s pecified nd easured n er ms of onvent ional pectral ransmittance curves, wherein ransmittance n ercent s plotted against wave ength n m*.

r

Z.M Spherical aberration. Spherica l aberration is defined as an optical defect in w h i c h rays of light through different narrow annular ones f h e en s concentr ic with h e

optical axis) rom n xial bject o int o not c o m e to ocus n h e am e plane. W h e n required, he imits n pherical berration may e pecified s h e ifference n o c a l position or ight hr o ugh n nnular o ne of given width nd radius and that for light through th e axiai zone of a radius approach- ing zero. It sha l l be negative w h e n th e foca l distance for th e o ne of specified adius h as the greater value. It m ay also be specified by means of urve n w h i c h he o ca l iffe-

rence s lotted against zone adius for different ones . h en pecifying pherical aberration, the c o l or o r wave length of light used nd whether measured at infinite o r at finite ocus shal l be specified. See .1.2.18.) Figure 6 s plotted s an xample of spherical aberration.

z o

«5,1

* - o c u .

— + — -.02 *.Ci •A4

fOCAC CMAN«e (tin,) FI C U K E . Spherical Abtrratwn

3.6.9.1

ocal hift Focal

hift aused y spherical aberration is an important consideration. t m ay e pecified s hange f focus ither o r h e osition f greatest concentration" r for h e ha *e osition" s th e en s perture s hanged. t m ay lso be specified s h e ifference n o c u s etween these w o osit ions t iven perture.

3.6.9.1.1 Position of greatest concentra-

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•

Hon. he position, f reatest oncentra-

tion" 1 3 defined as the focus position at which the erial mage, bserved nder magnifica-

tion, hows he east mount f preading. Very oarse esolution harts make uitable object

3.6 .9 .1 .2 Haze osition. he haze osition" is defined as the focus position at which is btained he ighest esolution ven

though there is considerable light around the image of the target Haze osition should be determined with igh ontrast arget.

3.6 .10 Veiling glare. enses n ddition

to

ocusing

ight

o

he

mage

lane

may scatter ome ight more r ess widely ver the mage. his cattered ight owers he contrast f he mage. The cattering may be u e o umber f auses, uch s dirt or cratches n he ens urface, multiple reflections rom he urfaces, r eflections or cattering rom mounts. This on-ima«rc forming ight s eferred o s veiling y'are." The measure of veiling glare is:

V 100

E.

% (11)

where E, s he mage lluminance roduced by he glare ight, nd , s he otal mage illuminance roduced y mage ight lu 3 glare ight.

3.6 .11 ondenser haracteristics. on -

denser, which may onsist f ne r more elements and components, is usually intended for nterception f ertain ortion f he

light from source and concentration f this lieht on iven area r u ch manner hat the mage f his rea s atisfactorily llu-

minated n creen. The dequate descrip- tion f ondenser ncludes: ts quivalent foeatlength, he T/ umber f he perture ratio f he ystem with which hp givm

• V*1Hnr rl»r» rrpUm 0> t t o r m i "itnr tlrfit.•» "(U—" «witraat rendi t ion ." an d "u M eM e brilllanc«" whi c h as « oo«.

MIL-STD-150A12 May 959

area s o e maged, he istance f hisarea rom he front vei tex of the condenser

the distance f he ear ertex f he on -

denser rom he pecified ight ource. The

performance f a

ondenser should be speci-fied n ccordance with he est pecified n5 . 1 . 2 . 20 .

3.7 MISCELLANEOUS EATURES. ndescribing a ens umber f miscellaneousfeatures re ncountered hich o otdirectly elate o ny articular spect fthis tandard. hese re isted with efini-tive nd xplanatory data.

3.7.1 Performance designation. Lenses areoccasionally designated y he erformance

they re designed o upply elative to or-

rection f pecific eometrical berations,the hree esignations enerally mployed

being chromat, nastigmat, nd pochrc mat. hese erms re efined n eneralmanner s ollows.

3.7.1.1 Achromat. n chromat s ens

in which he EFL and BF have their ain??

the

ame

or

ight

f

wo designated

was*lengths. lso, he ther berration« -n

sufficiently well orrected or he se n-tended.

3.7.1.2 nastigmat. n nastigmat s

lens n which he stigmatic ifference s

zero for at least one zone n the image plane.

In uch ens he ther berrations resufficiently w«n orrected or he se n-

tended.

3.7.1.3 pachromat. n pochromat s

lens n which ateral nd ongitudinal hro-

matic berrations re maller han he ec -

ondary' petf riim esidual n rdinary lass

achromate, nd hree ave ength* rebrought o common ocus. he ther aber-rations re ufficiently well corrected or theu se ntended. n om e ases herein he color orrections re ot arried o he ulti-

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MIL-STD-150A 1 2 mar iw *

mate degree, th e lenses are sometimes called aemi-apochromats.

3.7.2 Reflection reducing coating*. Reflec- tion educing oatings n lass o ir ur-

faces f lements onsist f h in ilms f transparent ubstances. hese ubstances are so applied and their indices of refraction so hosen h at h ey o rm ermanent ard coatings which ubstantially educe eflec- tance at th e surfaces fo r th e spectral region to be used.

3.7.3 Environmental range. T h e m aximum range f emperature, ressure, umidity, vibration, nd iological onditions nder

which a lens can operate an d be stored con- stitute ts nvironmental ange. h e ange required depends upon th e intended ose. Ex- cept when" specified, h e metrical nd er - formance alues overed y iü s tandard apply to normal room temperature and pres- sure conditions.

3.74 Optical glass. Optical glass is a glass which uring manufacture s carefully controlled with respect to composit ion, melting,

heat reatment, nd ther rocessing n order h at ts ptical haracteristics, uch as ndices f efraction, ispersion, ransmittance, pectral ransmittance, reedom from irefringence, tmospheric tability, etc^ have th e values required fo r th e optical application fo r which it is to be «sed.

3.7.4.1 Refractive index. W h e n a ray is re- fracted at th e surface o f separation between air an d a medium, th e ratio o f th e sine of th e

angle f incidence n h e ir to th e in e o f th e ngle f efraction n h e medium s equal to th e refractive index o f th e medium.

3.7.4.2 Diepermon. Dispersion is th e difference in refractive index between th e C an d F lines o f hydrogen in th e absence o f more specific equirements).

S.7.4JL1 Diepertwe power. Dispersive

r

power is th e ratio o f th e dispersion from C and o h e efractive ndex f odium-

no—1.

3.7.4JL2 Abbe v number. T h e Abbe v num-

ber is th e reciprocal o f th e dispersive power an d s equal to n0—l)/(nf—no).

3.7.4.3 ouble efraction. W h e n ight ray s ransmitted hrough n nisotropic material, t s n eneral esolved nto wo rays olarized n erpendicular irections. Th i s henomenon s alled double efraction.'' t lso ccurs n omogeneous material uch s lass when lasticaHy e- formed or internally stressed. T h e maximum

difference n ndex f efraction or ays polarized in different directions is called th e "birefringence" f th e material.

3.7.4.4 hemical urability f laes. Chemical durability of glass is th e resistance which h e polished lass ample h ow s h e corroding ction f ater, tmospheric agencies, nd queous olutions f cids, bases, and salts.

3.7.5 nternal svrfacee. nternal on-optical urfaces o f lenses nd en s mounts contribute o eiling lare y ight eflected from them into th e image space. Consequent- ly , where eeded o s no t to ontribute to veiling lare, en s barrels nd, n o m e n- stances, ens ells hould e nife-edge baffled; en s dges, ounts, arrels, ells, seats, nd ores hould e inished with dull black light-absorbing material.

3J E A U T T DEFECTS. Beauty efects are hose mperfections of omponents an d elements of an ptical ystem which do no t affect h e ptical haracteristics. h ey re undesirable bu t m ay be accepted f they do no t cause a significant dsgi ad atio n ofimage quality r nvironroerHl tability. h e various mperfections lassified s eauty defects are as follows.

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3.8.1 Material defect*.

& £ X 1 Bubbiet. Bubbles are air o r gaseous inclusions entrapped witiiin th e glass.

3.8.1X1 eeds. Seeds are very small bubbles.

3X1X2 Air belle. A ir bells are irregularly shaped bubbles.

3X3X Crack». Cracks are shallow separa- t ions o r breaks in th e glass.

3X1.3 Feathers. Feathers re owdered surfaces folded into th e glass in th e pressing process.

3.8X4 Fold», or Jap». Folds, r aps, are areas n which h e lass as ee n olded upon itself bu t no t fused.

3.8X5 MtUdne*».. M i M n es s s aused y cloudy or müky areas within th e glass.

3.8.1.« tone». tones re ragments f undissolved material in th e glass.

3.8X7 Strain. Strain is tension within th e glass caused by inadequate annealing or im - proper mounting. t is an area of ndex f refraction differing from h e ominal.

3.8X8 Striae. Striae ar e steaks o r veins in the glass with th e index o f refraction differing from tha t o f th e body o f th e glass.

3.8X8.1 Ream». Reams re fine bands f

striae.

3.8X8.2 Cord». Cords are streaks f very heavy striae.

3.8.2 Manufacturing defect».

3.8X1 Blisters. Blisters re ubbles n cement layer.

MIL-STIV-150A12 M ay 959

3.8X2 vrns. urns re eddish taingenerally round n h e entral reas elements. h ey re sually aused y hdrying-up or glazing o f a polisher.

3.8X3 Cement tarts. Cement tarts rspots where h e components f ementelens ave tarted to eparate. h ey can small rregular pots between h e lementor run-ins at th e edge, insufficient cement, ocement at th e edge dissolved by a so lvent

3.8X3.1 un-ins. un-ins re emenseparations t th e edge o f cemented component.

3£X4 Chip». Chips are areas from whicglass as een roken w ay ro m th e urface, edge, o r bevel o f an optical element

3.8X5 rack». Cracks re breaks n hglass.

3X2.6 Dig». Digs are breaks o f th e polised urface f ound, val, quare, tshape ncluding its, oles, nd urfabroken bubbles.

3X2.6 .1 Dirt oles. ir t oles re ifilled with rouge.

3.8.2.7 Dirt. Dirt consists f dust liut, other oreign matter n h e urface r trapped in a cement layer.

3.8X8 Graynee» . Grayness s epresentby finely round areas indicating incompleo r improper polishing.

3.8X9 old ark». o ld arks marks on th e surface produced by mold '^c

3X8.10 Orange peel Orange peel is pcsrpolished urface, ock-marked ith ihaving much h e am e urface ppearanas th e skin o f an range

3.8X11 Poor olish. Poor olish erta

17

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M1L-STD-150A 12 May 95 9 to olished urfaces ontaining minute its of a gray or red color. They are gray grinding its n he urface f he lass, r ed grinding ints n which ouge as een o

deeply mbedded hat t as o e emoved by urther olishing.

3 . &2 . 1 2 cratches. Scratches re urrows or grooves in the surface of the glass caused by he emoval f lass, sually made y coarse rit, ragments f lass, harp ools,

etc, rubbed over the surface.

r3 .8 . 2 .13 mears, cum, ater pots, tc .

Smears, cum, water spots, tc, re esidue of vaporated r nevaporated oisture.

They re sually emovable y normal"

cleaning.

3.8 .2 .14 Stain. Stain s a discoloration f the glass surface, sually brown, lue, r reen, caused y he deposit f oreign matter, r

changes produced on the surface of the glass by hemical ction f om e ubstance with

the glass.

4. G E N E R A L E Q U I R E M E N T S

4 .1 MARKINGS

4.1.1 Lens markings. Lens markings, such as maximum perture, ocal ength, ield f view, nd erial umber hall e laced n

the ront of he ens el l r n he barrel f space imitations o equire. The ens ame and erial umber hall e ssigned y he manufacturer.

4.1.2 Cell marking. Lenses supplied in cells

or onstructed ith emovable ells hall have ll ells ermanently marked with t least he ast hree digits f he ens erial

number.

4.1.3 Maximum aperture. All types of lenses , xcept ypes nd XI, hall e marked with heir maximum perture tated ither as he elative perture, perture atio r

T-stop.

4 .1 .3 .1 he symbol for relative aperture of a ens hall e f/ ollowed y the numerical

value, or xample /2.0."

4.1 .3 .2 T he symbol or the T-stop of ens

shnl e T followed y pace nd hen he

numerical alue, or xample T 2 . 2 .

4.1.3.3 -numbrr}7 The ffective diameter

AJBaricaa lu4urf UM pmrtar» Martin««. 1*1 4.1—1»*0

of he maximum perture f he ens hall be t least 95 percent of the quotient obtained y ividing he marked ocal ength y the f-number corresponding to th e maximum

marked perture.

4.1.4 ris diaphragm ontrol marking.

4 .1 .4 .1 Full stop.17 The tandard eries f

diaphrr.gm markings, r stop openings, shall

be 0.7, 1.0, .4 , .0, .8 , 4.0 , .6 , 8, 1, 16 , 2 2 ,

32 . 4 b . 4 , 0, nd 2 8 .

4.1.4 .2 Maximum apertvre witte." he - number corresponding to the maximum aper- tnre, -number, r perture atio alue

marked need not be elected rom he bove series but shall e ollowed y he bove series of stop openings beginning with the ne::t largest number whenever practical nd ro- gressing as far as equired n he ndividual application; .g. , or n /1.9 ens he ia - phragm might be marked /1.9, 2 . 8 , .0 , .6 ,

8 . tc., f t was elieved hat o mark t f/1.9, .0, .8 , .0 . .6 , tc., ould onfuse

the marking at the /1.9 nd f the cale.

4.1 .4 .3 Fractional top aluer. n ddition

to he umbered alues, ach top may e

divided nto hree 'lho s'ons y ots r

marks not umbered), he ots eing t "thirds of a stop." e.g., 0.7, 0.8, 0.9,1.0, 1.12,

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1 . 2 6 , J> , .5, .7 , .0 , .2 , .5 , .8, .2 , .6 ,

U.0; 4.5, .0, 5.5 ;, .3 , .1 , .0, .0 , 0.0,

11.(3), 2 .7 , 4 .2 , 6, 8 , 0, 22.(6), 2 5, 28,

4.1.4 .4 olerance of marking. or ens

marked n elative pertures, f he etting for iven ndicated alue s made y ro-

ceeding rom arger o maller pening (to insure constancy of direction for elimina- tion f acklash), he marked alue hall not be in rror y more than ne-third f a stop plus r minus 2 ercent of he diameter r lus r minus 5 ercent.of he area f the ffective perture). Under similar onditions, f he ens s raduated n

T-stops, he rrors hall ot xceed one- tenth f top plus or minus ercent of the entral mage lluminance).

4.1 .5 Focal length.1*

M1L-STD-150A 12 M ay 9S 9

4.1.5.1 A ll enses which re. marked witfc

the quivalent ocal ength hall ndicate this value by the letters EFL followed by the numerical alue either n the English r the Metric ystem s required y he ndividual

application.

4.1.5 .2 The ccuracy f the marked ocal length shall be as equired by the individual application.

4.L5.3 Accuracy of focusing scales. Focus- ing scales, when equired, hall e accurately marked o ndicate the correct focus osition of the corresponding lens to an accuracy of fcds, where s N. s efined y

equation 2) n . 2 . 2 , nd s onstant which may e elated o he ircle f onfusion r he ermissible esolving ower. The value of C s determined y the individ- u al pplication.

5. DETAIL R E QUIR E ME N TS

5. 1 M E T H O D S OF EST N D M E A S - UREMENT. This section deals with methods of esting nd measuring roperties elated

to Photographic enses. n many ases articular details re ot rovided ut will e

determined by the ndividual application. Whenever lternate methods f esting r measuring re iven, he method hall e employed which is most convenient and which est grees with he ntended se f

the lens. W h e n this standard is used in reference o the rocurement of photographic lenses, only those tests specifically designated shall be used n the examination of the prod-

F fTrie":*B^ti,,,'C""""n Alr S

*»* *»l*« Arrant

- « T i rAB C A , R £ T D

""•»M » rr h i M e * ' "^ z

rt_%

* • *%

'"'*"• • inthr

* - « % Inch« C lncK « . o

rt r an d th, foe.1 W,«rtfc. .„ te »* m,rkw, ,„ f

r T rr*— «-'-«hHü .„ « .£ *° * tnrhtt. 1 7 inch*«. IS Inch« 24 >--»— ..j ,i_

#**»**. w ,u r:"« ~* « w , .

uct. The rocurement shall lso learly tate which ests pply o 00 ercent nspection and which ests re o e sed nly or he examination f samples.

5.1.1 est pparatus. he riteria o e used n udging he uitability f est p- paratus are as follows:

5.1.1.1 Coüimator. A rollimator is a device

b y which est bject pinholc, esolution chart, tc.,) s made o ppear at an nfinite distance rom he bserver. t ommonly

consists

f

well-corrected

elescope

bjective r atadioptric ystem with he est object mounted accurately in he focal plane. The oüimator perture elative o he ens shall e uch hat he ntrance upil f he lens s illed with ight f niform lum.-

nance rom very art f he ollimator field.

5.1.1.2 Optical ench and nodcl lide. The

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MIL-STD-150A 12 May 959 microscope objective n th e test bench shall have a numerical aperture " n sin a" greater than " n sin a" se e equation 2) n 3^2) of th e en s eing ested. W h e n xamining h e edge f h e ield f ens, h e umerical

aperture o f th e microscope objective shall be sufficiently arge o ermit t o ntercept both rincipal nd dge ays. lternately, th e microscope m ay be mounted on a vertical -pivot permitting this to be accomplished. In this case, th e axis o f th e pivot must pass through th e bject point o f th e microscope. Fo r eference, able h o w s h e numerical apertures nd heir orresponding -numbers.

TABLE

r

Naswrical mtaw f-numbw

0.01T5 f/28.7 0.0349 f/14.3 0.0523 1/9.55

0.0698 1/7.15 0.0872 1/5.74 0.1737 1/2^8 0.2588 1/1.93

0.3420 1/1.46 0.4226 1/1.18 0.5000 1/1.00

0.5736 1/0.872

0.6428 1/0.778 0.7071 1/0.707 0.7660 1/0.653 0.8192 1/0.610 0.8660 1/0.577 0.9063 1/0.552 0.9397 f/0.532 0.9659 1/0.-18

0.9848 f/0.508

0.896*. f/0.602 1.0000 1/0.500

5.1.1.3 Infinity. W h e n testing a lens at "infinite" focus by means o f a target at a finite distance, th e distance 3hall be considered approximately nfinite when t s greater than D measured in feet

fD 00 d (12)

where d is th e diameter o f th e effective aperture n nches, nd s h e EFL n nches

o f h e en s eing tested. h e istance D s no t o e sed n etermining th e EFL directly, nless suitable orrection s made fo r th e plane o f best infinite focus. However, a istance D may be sed o r ocusing an d

checking esolution f ixed ocus ameras an d ones t nfinity. Fo r checking nfinity focus esolution only, designated alues less than that of D in formula 12) m ay be used unless, as in some cases, there is a noticeable loss in resolving power when a lens intended fo r use at infinity is tested at finite distance.

5X1.4 White light. W h i t e l ight will usually be used n onducting all tests. Fo r most photographic tests, th e spectral omposit ion

o f "white light" is no t critical an d any source o f ight, rdinarily onsidered ree ro m color, m ay e sed. o r urposes f h is standard, white light is defined as black body radiation f 750°K o 000°K- W h e n e- quired, h e white ight m ay be filtered to a particular olor. T h e etailed pecification shall state whether or no t th e filters supplied with th e lens shall be used when conducting resolving power tests.)

5.1.1.4.1 Flash discharge lamps. Flash discharge amps will e ermitted o r makinjr test exposures provided care is taken to n- sure controlled charging o f th e lamp conden- se r so that successive exposures ar e approximately qual uring h e hotographic est- in g process.

5.1X5 Photographic plates nd fUm. T h e photographic ensitized aterial nd h e processing used in th e testing o f al l types o f lenses hall e h e inds o st ommonly

used with th e type o f lens being tested. See 5.1.212.1.)

511.6 Test conditions. Unless particularly required y th e ntended ses, ll ests nd measurements shall be conducted wilier H O T « mal o om onditions.

5.1.1.7 Resolving ower target. h e e-

2 0

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MIL-STEM 50A 12 May 95 9 value of ß. or many photographic purpose« the distortion is negligible for points distant from the center of the useful field not more than one-fifth of its adius, an d consequent- ly, t will very ften be possible to obtain a satisfactorily ccurate alue f he FL by a single etermination of ß nd /for a point ying ear th e xis.

5.1.2-2.1.1 ethod A ombination method. he EFL lso may e etermined by dding he hotographic BF to the istance ro m he ear vertex to the emergent nodal oint he latter istance m ay be e- termined by Method 2 .

5.1.2.2.2 Method S — Nodal slide method. T he lens to be tested shall be mounted n a nodal lide o rotate about th e vertical xis through its second nodal point T he distance from this nodal point to the position of best axial ocus or n nfinitely distant bject point shall be measured. This is also known as th e second principal "focus. An important factor r ncertainty n sing this method is th e difference between the position of best focus as judged visually on the optical bench and the best focus as determined photograph-

ically by method 1). When using this method, he riterion or etermining he est axial focus should be specified. T he criterion used s dependent on the type of test objsct or target used an d may be specified in terms of either the haze position or th e position of greatest oncentration see .6.9.1.1 nd 8.6 .9 .1 .2) r n erms f he olor n nd

around the image.

5.1.2.3 alibrated ocal ength. When e-

termining he alibrated ocal ength, he plane f est verage efinition hall e chosen s he ocal lane. o ompute he calibrated focal length, le t /„ «/,. etc, repre- sent he istances n he ocal lane ro m the xial oint o he maues f »R**ety distant bject oints yin* n he directions making ngles ßu t, tc.. with he ptical axis f he objective. f s he quivalent

focal length in the absence of distortion, then /

(13)

(14)

(15)

yx - an i Y, an ß,

and /. an m

In the resence of istortion y\ > an i x Yi y, an t /,

and /. an . /. 16 ) T he added terms are the values of the linear distortion for values ßlt ß» etc, respectively. T he values of /an d ß are measured directly. It is evident that the individual values of the distortion efined y he bove roup f equations an e hanged y hanging he

value of f. If f is th e equivalent focal length, in many instances values of the distortion in the eighborhood f he xial mage oint will be mall, nd near the edge of the field the alues will e arge nd redominantly negative or positive. Infinitely distant targets m ay e rovided y roup of ollimators or y ne ollimator which an e ucces- sively laced n he equired ngular ositions. Exposures shall be made an d the /corresponding o ach ngular istance ro m th e optical axis shall e determined.

5.1.2.4 B a ck focal distance. T o determine the F, he focal lane n he mage pace shall e etermined y isual r hotographic method. T he measured distance from this ocal lane o he ertex f he ack surface of the lens shall be the required B F.

5.1.2.6 lan** ocal distance. o etermine he D , he ocal lane n he mage space hall e etermined y isual r photographic ethod. he easurement shall be made from the plane of the locating surface or th e flange to the focal plane.

5.1.2.6 ront ocal istance.1 o eter-

mine he F. he ocal lane n he bject space hall e determined y i visual <

f

22

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photographic method. T h e measured distance from h is oca l lane o h e ertex f h e front surface f h e en s hall e equired FF.

5.1.2.7 Front vertex ack ocal istance.

T o etermine h e FVD, h e oca l lane n th e mage shall be determined by a visual o r photographic ethod . h e easured is - tance ro m h e ertex f th e f ron t urface o f h e en s o h e o ca l lane hall e h e required FVD.

5.1.2.8 Aperture ratio. Fo r th e special case in hich h e bject s t nfinite istance (magnification ), , h e irst member o f h e atio quation 2) n JL2, m ay be

determined s h e uotient btained when th e EFL s ivided y h e iameter o f th e effective aperture.

5.L2.8J Fo r th e general case in which th e magnification m ay ave ny alue, in - hole should be mounted at th e axial oint of th e esired mage lane, nd h e ngle of th e cone o f light emerging through th e pinhole ro m h e lens hould be etermined by measuring h e iameter of ight ection

o f th e cone at a suitable distance beyond th e pinhole. T h e angle a can be calculated from th e measurements and ubstituted n quation 2). f n s h e index f refraction of th e medium n which h e ngle o s measured n = fo r air, sed in th e reat m a- jority f cases), h e econd member of th e

1 aperture atio s

2n in a W h e n measuring h e aperture atio y h e

method f this paragraph, h e angular ub- tense f th e bject point t h e irst odal point o f th e photographic objective must be small s ompared ith h e alue f h e angle between h e optical xis f h e b- jective nd h e xtreme ay roceeding o th e image point.

5.1X9 Effective aperture.

M&-CTD-150A 12 Mo? "St

5.1.2J.1 ethod — Microscope method,** A raveling ompound icroscope s required ith eans o r ranslating h e microscope n a direction t right angles to its optical axis through a measured distance no t ess than h e diameter o f th e m aximum

effective aperture to be measured. T h e microscope must e f ow ower 10X o 0X ) provided with reticle nd with a working distance sufficiently long to permit th e microscope to be focused on th e limiting opening o f h e hotographic bjective hrough h e front member. T h e photographic objective, o f which h e ffective perture s o be measured, shall e mounted n a convenient position o ermit h e raveling microscope o be directed parallel to th e optical axis of th e objective nd focused po n h e edge f th e opening aving h e mallest pparent ia - meter. T h e hotographic bjective s o t to e isassembled.) h is dge hall e viewed through th e lens elements which are normally raversed y mage-forming ight before assing hrough h e imiting pening. icroscope aving o ng working distance is equired to avoid mechanical n- terference h en ooking hrough h e en s elements. A microscope hall h en e trav-

ersed nd measurements made to determine th e apparent diameter o f this opening which shall e h e effective apettur. n lace o f traveling microscope, a suitable contour projector m ay e mployed to measure h e ef - fective aperture. If th e lens h as a non-circu- la r aperture, th e measured diameter must be suitably corrected.

5.1.2.9.2 Method — Point ovree method. W h e n t s o t racticable o se

microscope o f sufficient working distance to permit h e imiting pening to be bserved through th e lens elements, s source o f light, as mall s racticable nd mitting o ne sufficiently arge o ill h e ens, ay e

»Awte uatmri

S M4. M. I MI . tarhu tafeftf »«*»*« a)lto«tiMi t Mod« ieten

23

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MIL-STD-150A 12 Moy 959 placed t he econd rincipal ocus nd directed oward the bjective; he iameter of he mergent eam hould e measured as near the front of the objective as is prac- ticable. This method is subject to a systema-

tic rror, he alue btained lways eing too arge, ecause f he inite ize f he source.

5.1.2.10 -number and transmittance. he equipment specified n methods nd or determining -stops nd transmittance f a lens epresents orkable pparatus. ow - ever, odifications re ermitted rovided that he asic equirements f he method an d he pecified ccuracy re met S ee

3.2 .6 an d .1.4.4.)

5.1.2.10.1 ethod Extended ource method.** This method of lens calibration is based n illing the ens with light from n extended uniform source of adequate size an d placing in th e plane of best definition of th e lens a metal late with a hole, the diameter of which hall not exceed 3 millimeters or 1.5 millimeters for 8-millimeter film), at its center. he ight iu x assing hrough he hole hall e easured y hotocell r- rangement. This fiux shall then be compared with he lu x assing through a hole f the same dimensions from an open circular aperture f uch ize nd t u ch istance from he late hat t subtends he esired angle o hat in f c , where s he T-number o e measured. he reatest are s ecessary to nsure hat he xtended ource s niform. n ractice, the photocell eading for

each whole T-number is first determined for a series of open apertures at a fixed distance from he late. he lens is then ubstituted for the open perture with he -millimeter hole ccurately n ts ocal lane nd he iris f he lens closed own until the photocell meter eading roduced y he ens s equal o ach f he uccessive pe n oi?

» h» footnote IT.

i eadings. he full T-stop positions are then marked n the iaphragm ring of the ens. The ntermediate hirds f tops ay e found with ufficient accuracy y nserting a neutral density filter of 0.1 an d 0.2 behind

each pe n perture n urn nd oting th e corresponding hotocell eadings r y i- viding the ravel f he iaphragm ontrol into hree equal arts. T he extended source should e niformly right ve r ts seful area o within ±3 ercent This ould e tested with uitable elephotometer, r small ole in n paque creen ould e moved round n ront f he ource nd any consequent variations in photocell reading oted.) he ource may be heet f

ground glass covering a hole in a whitelined box containing several lamps mounted around the hole an d hielded so that no direct lightfrom he amps alls n he round lass itself. he hotocell eceiver may be f he phototube ype with imple -c mplifier. Care mu st e aken o nsure hat hoto- tube ensitivity oe s ot hange etween marking readings on the open aperture nd on the lens itself. T o guard against this, some turret rrangement s esirable, ith he lens on on e side an d the open aperture on the other, o that the tw o may be interchanged and ompared uickly with ach ther y turning he turret ransmittance of a ens shall e measured t the maximum elative aperture in a direction parallel to the optical axis f he ens. ransmittance s qual o C/R where C is th e calibrated photocell read- in g with the lens in place, an d R is a similar reading when clear circular aperture s in place, ubtending an ngle at the hole n the ront f he photocell o that in a =

i^N, where N is the second term in the aperture ratio of the lens to be tested. S ee S.2£ . ) T he value of N mu st be th e true value, which may iffer rom hat ndicated n he ar-

rel.

5.1.2.10.2 Method — oUimator ethod.

1* In this method, light rom a small

r

" M lootnnU 17 . U.

2 4

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source (a millimeter o le overed ith opal glass an d strongly illuminated from behind) hall e ollimated y a imple ens, or an achromat if preferred, o f a focal length at least three times th e EFL o f th e lens be-

in g tested and of sufficient aperture to fill th e lens eing alibrated. h is ives ollimated eam which will e ocused y h e test lens to form a small circle o f l ight in it s focal plane. h is circle of l ight will e less than h e rescribed imit of millimeters diameter. Uniformity o f th e collimated beam can e hecked y moving mall o le n an paque screen across h e beam, nd n o t h - in g any variations n th e photocel l reading. Fo r th e comparison nit, n pen perture

shall be used, of diameter equal to th e f oca l length o f th e lens divided by th e esired T - xmmber. T h i s aperture shall first be mounted in front of an integrating sphere o f adequate size with th e sual photocel l etector an d h e ight ro m h e ollimator llowed to nter h e perture. h e perture late shall then e eplaced y th e lens, h e ris diaphragm losed o wn o iv e h e am e photocell eading, an d th e -number en - graved n h e ris ing. h e ntermediate

thirds o f stops can be found by using 0.1 o r 0.2 density filters, r by ividing th e ravel o f h e iaphragm ontrol nto hree qual parts. T o guard gainst "drift" or line-volt- age ariations which might ccur etween readings o f th e comparison aperture an d th e lens, t s mvenient o eave h e nown standard perture n lace n ront of h e sphere, and to nsert th e Tens nto th e beam in uc h position h at h e mall mage of th e source alls whol ly within th e standard

aperture. T h e meter reading should then re- main th e same wjtfc th e lens in or out o f th e beam. econd late with -millimeter aperture should t* laced over th e compari- so n perture while h e en s s n lace o stop any stray l*fht which may e eflected from h e nterior f h e ens. t hould e noted articularly h at f h is ethod s mmd, fes focal ength f h e en s must e

MIUSTÜ-150A 12 M ay W S»

measured eparately nd uitable et f open apertures onstructed fo r use with t. However, by suitable devices, o ne single se t o f fixed apertures m ay be used fo r al l lenses. Transmittance o f a lens shall be measured at

th e f t T J T n T t t r t elative perture n irection arallel to th e optical xis o f th e ens. Transmittance s qual to C/E where C is th e alibrated hotocel l eading it h h e lens in place, and R is a similar reading when a clear diaphragm (equal to th e lens effective aperture) s in place.

5.1.2.11 Relative iOumination.

5.1X11.1 ethod — Extended ource method. T h i s method of measuring relative illumination makes use o f th e same appara- tu s nd echniques pecified n method . W i t h th e lens o be measured et up in th e apparartus, h e photocel l hall e isplaced laterally tc th e position corresponding to th e required ngular ositions, nd th e orresponding percentage o f axial illuminance fo r each osition s ound ro m alibration curve of h e photocell meter.

5.1.2.11.2 Method S — Collimator method.

T h i s method of measuring relative illumination makes se of th e ame pparatus nd techniques pecified n method . With h e lens to be measured se t up in th e apparatus, th e lens shall be rotated through th e desired field ngles nd h e hotocel l eadings compared * r i f c h th e eadingB fo r th e lens on axis. h e percentage o f l ight flux transmitted an then e read o ff a alibration curve fo r h e hotocel l ystem nd onverted o desired ercentage lluminance y ividing

by cos» ß.

5.1.2-11.3 Method 9 — Densit ometric method. This method of measuring relative llumination makes se of th e am e apparatus an d techniques as specified n method» 5 a»d 6 , except that a photographic plate is substi- tuted o r h e hotocel l when h e xtended source is used, snd fo r th e integrating sphere

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MII-STO-150A 12 May 19» when a collimator is used. In th e latter case, th e mage roduced y h e en s hould e in harp ocus n th e mulsion lane. h e exposures are made n h e axis nd at h e required angular positions off axis. h e x-

posure imes hall e h e am e t ll h e positions. T h e ensities f th e xposed nd developed images shall be measured an d th e relative Uuminance etermined sing h e sensitometric curve o f th e emulsion» obtain- e d y exposing a calibrated step-wedge.

5.1.2.11.4 Method 10 — Indirect amputa-

tion method. T h e indirect computation o f illuminance istribution ro m imensions f th e en s re utlined n h is ection. h e method in this case is fo r a lens while in th e design stages, o r n determining th e illuminance distribution of an actual lens when no convenient hotometric quipment s vailable.

5.1.2.1L4.1 Distortionless lent with object at infinity. T h e ase where th e bject s t infinity s pplicable o most hotographic objectives «encountered n aerial nd round photography. T h e field angle of such lens

is lways xpressed y th e bliquity ngle * , n h e bject pace. T h e esired elative illumination is given by :

R cosV 17)

^here E s h e lluminance t h e oint n th e image which corresponds to th e obliquity angle > n h e bject pace, nd E, s h e illuminance at th e center o f th e field. S* an d

S « re , espectively, h e beam ection reas o f th e oblique an d axial beams at th e chosen reference plane in th e object space. T h e area S* will in general be smaller than S * du e to vignetting, ut n ome nsual enses. $ may be somewhat reater h an ~

5.1JLU.4.2 Distortionless ens with inite object istance. T h e elative llumination R can be computed ither n h e bject pace

or n h e mage pace epending on which is more convenient T h e illuminance at angle

> is given by th e integral:

E> = /cos*edS K'/cosV S' (18)

where K nd K ' re onstants ndependent o f bliquity. h e ntegrals re o e aken over h e espective eam ections. h e n- tegrals re necessary because * an d ¥ vary from point to oint over th e beam sections. If th e aperture is small, th e integral becomes unnecessary nd hen:

E* Se cos** = K'S'e os4*' (M )

T h e elative llumination s then ound y evaluating E> nd « o r n blique nd

axial beam an d taking th e ratio R =EVE..

5.L2J1.4.3 Distorting lens with object at

infinity. T h i s differs from th e previous case because th e distortion will have a considerable effect on th e distribution of illuminance expressed as a function o f th e entering obliquity ngle . n h is ase h e elative l- lumination ecomes:

E* S* f* in co s R

E, f c ' dh')

(d*) (20)

S* an d S « are th e areas o f th e beam sections fo r th e oblique an d axial beams at th e chosen reference plane in th e object space; ♦ is th e obliquity ngle n h e bject pace, s h e focal ength o f th e lens an d h ' is h e mage height. y easurements r omputations on h e ens, elation an e stablished

connecting ' with . ro m which th e value o f th e derivative dh'/d* can be found at any desired oint n h e ield. Fo r istortion- l«w ens, ' an : n h at pecial ase nation. (20) simplifies o quation (17).

5.1.2.11.4-4 Distorting ens unth Unit* b-

ifc.t distance. T h e imajre space equations (18) o r 19) oH independent of th e distortion o f

r

8/14/2019 Mil Std 150a


th e ens. f t e esired o se h e ata of

th e object space, quation 18) ec omes:

Ee Jo s«

(dh)

dS (21 )

wher e s onstant ifferent ro m hat used n equation 18), h s th e object height, and ' h e height of h e mage of that b- ject. T h e derivative dh'/dh mu st be found by determining n lgebraic elationship e- tween h nd ' . f th e perture s ufficiently mall , il l o t ary reatly ver he beam ect ion nd he quation ay e e-

duced o the approximate f o r m.

Ee h' d h ' )

(dh)

S os**

(22) 5.1.2.11.4.5 Monocentric ens. n h e ase

of a en s having a o m m o n enter of urvature o ll he urfaces nd oncentr ic

image

surface,

h e elative

l lumination c o n -

tains only o ne cos ine , amely :

E* Se R cos* 23)

5.1.2.12 Resolving power. W h e n pecifying o r measuring esolving ower, are hoirid be taken o consider h e ollowing ertinent factors: e t ho ds f ests, ontrast of arget sed, in d f nd rocess ing of h o t o -

sensitive muls ion , hether ilter s o e used, nd agnificat ion t w hi c h esolving power arget mages re ead. o r eading resolut ion, a#T.mcation f hr owes t power which permit* convenient viewing will yield h e highest esolution eading*. The rule ased n elwyn's xperiment ?0

h at

• t W. . S«iwTT< N.Uon.1 (form« f u n i l < > < < > M«. ) >

UM nd MbM*r*»*4*t „„1 M. 9. 1M B

MIUSTIM50A »May fS*

the umerical alue f h e agnificat ion should qual h e umber of ines per millimeter xpected o e esolved an e o n- sidered ule of thumb.)

5.1.2.12.1 hotographic esolving ower. W h e n onduct ing h o tograp h i c esolving p ower tests by m e t h o d s 11 and 12, the photosensitive material nd processing ho u ld e in ac c ordanc e with table II .

5.1.2J2.1.1 Method 11 — Collimaior meth-

od.*1 o r enses rimarily ntended or se

o n distant objects, uc h s ypes , I. ll, and V, h is met ho d ho u ld e sed. h e e- solving power arget s laced at he rin-

c ipal o c u s of o l l imator nd l luminated with white light A ilter of a pecified c o l or may e sed nd t ha l l e placed etween the light source nd h e arget t s e c om - mended that in rder to liminate vibration effects, a flash discharge lamp be used as th e light ou rc e nd hat h e ight rom t e filtered f ecessary o pproximate white light See .1.1.4.) xposure an e o n- trol led y mea n s f eutral density ilters between th e light o ur ce and h e target T h e

lens to e tested ha l l e laced n ine cofti- mated ea m ro m h e target nd test plate or ilm made n eries of f o c a l ettings s described n .1.2.1. nless otherwise pe- cif ied, h e ens ha l l e et t he pecified maximum elative perture. ith he est plate perpend icular to the optical axis of th e lens, exposure hal l e made of th e test arget t h e pecified ngular istance ro m

the xis ut o .nd nc luding h e multiple of he pecified ngle alling earest h e c orner of th e late inside th e picture format The pecified r.gie hould e multiples » f Wi egrees and hou l d e paced o «rovide 5 ncrement» o r m o r e n h e semi-fieki of th e lens. h e rposttr? im e ha l l e h e am ? for ll nrular ettings nd ha l l e h e

" » —«K a< 1. f > w wWm r*vr o Muvml r »

tlclnit rp«c o* int« »i l f lui»rt*< i h» arwt. TL f fc*

foJLaulor. —4 FI. f M ac t o n * . M -ahta bmtU » **

"».•tad ? raKJ >* ;> . ( uUr . l lm» y ht .wlnr i hm o V * mrii MM) abccntlal IIMB j the »• f k* tsü» uiik.

n

8/14/2019 Mil Std 150a


MIL-ST1M50A 12 Moy 959 r

TABLE U

Pboteamai t iv* ASA Drrtlopna«t Lenatrp* Material Exposure Index IfUU»)

I

(70-mm.

o r m a t Panchromat i c erial 10 2. 0 .1 0 & smaller) (5-inch o r m a t Panchromat i c erial 80 1. 5 .1 0 & larger)

II (70-mm. o r m a t Panchromat i c erial 10 2.0 t .1 0

& maller) 5-inch ormat Panchromat i c erial 80 1.5 ± .1 0

& arger) III Panchromat i erial 50 0. 8 .1 0 IV Panchromat i c microfi lm Maximum ontrast

V Panchromat i c (mot i on icture) 50-80 0.6 .1 0 IX Panchromat i c portrait) 100 0.6 .1 0

XII Panchromat i c microfi lm Maximum ontrast

XIII Panchromat i c microfi lm ... Maximum ontrast X IV Blue ensitive.recording ... 1. 5 .1 0

exposure ime which ives he ighest e- solving power at the angular setting- nearest the ngle qual o ne-half he alf ngle of view. The different angular ettings may be obtained by moving the lens and test plate about an axis near the entrance pupil r b y moving he ollimators, r y means f series f ollimators laced n he orrect

angular ositions. he ens may e ested with r without he ilter rovided with t, as required.

5.1.2.12.1.2 Method S — arget ange

method. or enses rimarily ntended or use at finite distances, such as types IV, XII, and XIII, his method hould e used. Also, it may e sed, when pecified, or esting other ypes f enses. Properly lluminated high ontrast esolving- ower targets hall

be placed

n

he

bject space

n

plane

erpendicular o he ptical xis f the ens o

be tested and spaced t the equired ngular distances. The distance rom he ens o he plane f he argets hall e esignated. When his method s se d or testing lenses

at nfinity ocus, ither ormula 12) n

5.1.1.3 may e se d o determine th e roper distance, r om e designated istance may be used. The test late shall be adjusted er-

pendicular to the optical axis of the lens and exposed or maximum esolution t the arget earest he ngle qual o ne-half he half ngle f iew f he ens eing ested and hall e moved n eries f focal ettings s described n .1 .2.1. The ensitized material, processing, etc, shall be n ccordance with table I.

5.1.2 .12 .2 Method S isual esolving power. When isual esolving ower measurements re equired such s ype lenses), hey will e made xactly ik e he photographic esolving ower ests, xcept that he erial mage, when t s eal nd easily vailable, will e bserved isually trader magnification. Method 1 r 2 n 5.15.12.1 will e sed s pecified, epending n he se f he ens . W h e n he mage

formed y iewfinder type ens) s virtual mage, elescope topped ow n o

5 millimeters nd laced t he ye osition will e sed o bserve he mage. n his cast he esolution hall e determined n

tpm f pecifiod est hart t pe -

cified distance. n ll ases where he mage

is formed on a ground glass, the ground glass shall be removed n observe the aerial image,

and he mage hall e bserved n lane.

9

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MIUSTtM50A1 2 Moy W9

5Ü1L3 Method U — rojected hoto-

graphic resolving power. This test is intend-

ed to be used primarily fo r enlarging lenses

(type VI). arget late f he equired size containing resolving power target« (light ines n ar k ackground) nd f

the required ange, nd located as shown n Figure 8, with on e set of the lines in tangential an d the other set in radial direction, shall be placed in the object plane film plane) f the lens to be tested. The targets shall be of

high contrast. T he target plate shall be even- ly lluminated y ight rom ondensing source. If required, the light shall be filtered to the olor required y lacing ilter between the light source an d he arget plate. With the optical axis of the lens perpendicular to the target late, he ens shall be fo -

cused t he esignated magnification nd aperture, an d an exposure ade on th e designated photosensitive material. T he photosensitive material hall e held ia t in a plane perpendicular to th e ptical xis f the lens. he correct exposure hall e hat which gives the maximum resolution at position f igure . he est late s ro - cessed in the required manner. T he resolving power hall e ead y bserving he ry test plate nder suitable magnification. he figures eferred o n measuring esolving

power y his ethod re he ines er millimeter on he arget plate. t s ecommended that enlarging lens« be ested t a magnification f :2 using medium contrast glossy hlorobromide aper rocessed V£ minutes n 72 eveloper, diluted :2 t C8°F.

5.11.12.4 ethod 5 — rojected visual

retotvino power** This test is intended to be used rimarily or rojection enses type

VII). A test object of the

equired

ize

on - taining high contrast resolving power targets (dark lines on ight background) f tW re - quired ranye an d laced as shown n Fijrure

to r Datwmbitar ft—Win •I UHM la frohiU in (« II in S ii füm <« 4

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FlCtm . rojected eeoLvinff ower Tctl late

under est pon atte, hite, Tainless screen. This screen shall be located at such a 8 hall e rojected y means f he en s distance from the projector that unless otherwise specified the long dimension of the pro-

jected

mage will e t

east

0

nches >

order that the observer will have no difficulty in distinguishing the nu mber of lines resolved. he resolving power f the en s t an y point n ine ield s he argest umber f lines pe r millimeter in the teat object that an observer, close c the creen, ee s efinitely resolved easily counted) n both radial an d tangential directions in the projected image. Care shall be taker, to inäur« that the screen is erpendicular c fco ptical xis f the projection ens, an d hat the lens s fanned

so hat he mage t he enter of he est plate has maximum ontrast. The rojector used n his est may e egular production model r pecial est projector. he glass test object hall e iat an d eld concentric with nd ormal o the ptical xia of the projection lens. T he cone of light from the rojection am p hrough ondensing system hall completely fill the entrance pupil of he projection ens. he est object & & 4 l i be uniformly lluminated.

5.L2.13 stigmatism nd urvature f

fieid,

5.1.2.13.1 ethod S — ietolviv.g power

ta x pe t method. By meana of an y of the methods fo r measuriiic arolvluR power sp?cifird

in methods 1 hrough 6 . esolving ower

2 9

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MIUSTD-150A 12 May M*

shall e etermined or ifferent ositions

of the test late n he mage pace. The test

plate r lates are xposed n mall teps, at

different distances long he ptical xis f

the ens. he ength f ach te p epends

upon he orrections, focal ength, nd perture f he en s eing ested. ufficiently

large umber f teps hall e aken o n-

sure t east hree teps on ach id e of he

best ocus osition or oth adial nd an-

gential ines t ny ngular osition. Upon

reading the targets, the position of best focus

shall e determined for adial nd angen-

tial lines separately) t which the resolution

is a maximum at each ngular setting. These

focus ositions re lotted gainst ngular settings, nd wo urves epresenting he

tw o mage surfaces are btained. The urve

representing urvature f ield s median drawn etween he wo urves epresenting the mage urfaces. S ee . 6 .3 . ) he stigmatic ifference s btained y aking he difference n he ocal etting t pecific

angle or the wo mage urfaces.

5.1.2.13.2 M ethod 1? — Nodal nlide method.

This method may be sed n ieu f method

16 . In his method he en s o be tested hall

b e et p n ront f uitable ollimator

equipped ith arjret ontaininc ertical

and horizontal lines nd centered so that the optical xis is arallel o he collimator xis and coincident with he axis of the observing microscope. he ens hall e oved long

the microscope xis ntil he xis f ota-

tion f he odal lide ntersects he ear node. The microscope shall be focused on he

axial mage nd he osition f he micro-

scope oted.' T he ens haJ) hen e otated

about he xis hrough he ear od e nd

perpendicular to the optical xis of the lens.

At multiples f ngular ositions f Vi

decrees u t o he dg e f he ield, he

microscope shall be seDaratelv focused on the

radid nd angential line«. The focal hanee

from he xis osition hall e oted t he

antuhir ield ositions or he adial nd

tangential ines. o btain urves uch s

specified n ethod 6 . he actor (l- cos ?)/cos s ubtracted rom he micro-

scope ettings, nd his ifference s multi-

plied y the cos ß. f a ia t ield ar s se d

at he microscope t s ot ecessary to sub-

tract he actor (l-cos )/cos . he n

curves are obtained, the procedure for determining the urvature f field s he same s

that n method 6 .

5.1.2.14 olor orrection. W h e n he image

quality s ound satisfactory on he asis f

other pplicable ests, he olor orrection

ca n also be considered as satisfactory. Direct

measurements f olor orrections ay e

needed when some special color requirements

are o e m et hese measurements may e

specified n erms f inimum esolving

power r imits n ndividual olor orrections.

5.1.2.14.1 ongitudinal hromatic berra-

tion.

5.1.2.14.1.1 ethod 8 hotographic

method. Photceraphic resolvinjr power meas-

urmenents hall e ad e s pecified n

method 1 r 2 . tüi-ing light of the colors

designated, epeating the test for each color.

The ight se d may e upplied y mono-

chromster r t may e iltered white ight, as pecified. he ocus ositions t hich

the maximum esolving ower A W A R n-

less otherwise pecified) s btained shall e

determined or ac h olor. The ongitudinal

color aberration or articular color s the

difference n ocal ettinr for-this color an d

white ieht, r or his olor nd pecified

color. When he ocal etting or he irst

color s greater than he focal setting for the

reference olor r whit* ight, he ongitu-

dinal hromatic berration s aid o e

posi ve . enerally, he eference olor

shot d e owards he ed nd f he pe c

tral ange nder onsideration.

5.1.2.14.1.2 Method 9 — Nodal ilide metli-

öd. he n pecified, odal lide ptical

S O

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bench m ay e sed nstead of a est ca mera as n m e t h o d 8.

5.L2.14 .2 Lateral chromatic aberration.


method. ho togra phic easurements hal l be ma de n he lane f es t average efinition or white g r h t r pecified eference co lor . T h e image sizes y\, /., tc are measured, s pecified n method , or ifferent co lors . T h e lateral co l or aberration t a articular angle is th e difference between /for th e articular o l or nd / or h e hite light r h e pecified eference olor .

5.1.2.14.2.2 Method 21 —Nodal slide method. h en pecified, oda l lide ptical bench may e sed nstead of test came ra in m e t h o d 0. Lateral hromat i c berration shal l e easured y moving h e ptical bench microscope long a cale erpendicu- la r o he axis f h e ptical ench , irst sighting th e micros cope on the image f orme d by using white ight, r ight of h e econd specified o lor . W h e n etting th e micros cope fo r measurements at each angle ß, th e microscope ha l l be displaced along ts orizonta l

axis y the distance (l-cos 0) /cos ß away from he ens. This efocusing s no t ecessary if a flat field ba r is used. This setting of th e microscope s maintained t ach ngle for all the colors. T h e distance t hrough w h i c h the micros cope is . moved laterally, divided by the cosine of the angle at w h i c h the measure- me nt is ma de , s th e ateral hroma t i c aber- rat ion .

5.1.2.15 Magnification.

5.1.2.15.1 Paraxial magnification.

5.1.2.15.1.1 ethod it hotographic

method . The PM hal l e measured y plac- in g photograph i c plate in the mage plane conjugate with he object lane t h e pe-

MIL-STD-150A 2 May 1W

cified inite istance ro m h e ens. ithin th e ntended ield f overage n h e bject plane, eries f eticles s laced t c - curately etermined istances /„ /., tc, from a eticle at th e axial object point . T h e

exact ocat ion f his oint s o t eeded, an d ny oint n h e icinity of h e nter- section " o f th e lens axis with th e object plane m ay erve s eference o r measuring istances y.) ho togra ph s aken of th e r- ray of th e reticles. O n th e resulting negative, measurements ha l l e made f h e orresponding istances /„ /.., tc, ro m h e image of he xial eticle o h e ther e- ticles, nd h e uotients y',/y'1 , V??. tc, are formed. T h e limiting value of these qu o tients as y approache s zero is th e PM . Fo r a

photographic en s ree ro m istortion, h e quot ient is invariant with respect to th e value of . Fo r m a n y ho togra phic urposes h e distortion s egligible o r oints istant from h e enter of the seful field o t more than ne-fifth of ts adius, nd onsequent- ly t will e very often ossible to btain sufficiently ccurate alue of h e M y single determinat ion of y an d /fo r a o int lying near the axis.

5.1.2.15.1.2 Method 8 — Visual method.

T h i s method s imilar o meth od 2 xcept that th e istances -/ o th e aerial mages f th e eticles re easured irectly n h e image plane by means of a suitable measur- in g evice. h e etailed pecificat ion hal l state h e m e t h o d se d o r etermining th e plane in w h i c h he measurements re o e made.

5.1.2.15.2 Method 2 1 * — Calibrated magnification. T o ompute h e alibrated magnifi-

cat ion, et /„ y„ tc . , epresent he is - tances , n he pecified mage lane, ro m

th e xial mage point o h e ma ges of h e object oints ying n he object lane t the istances „ „ tc, rom h e xial object point f m is th e paraxial magnification, then n he bsence of distortion

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•/» ylr y, m/,, . /. y. (24)

ID h e presence o f distortion,

y, =m y, -/,, /t y. y. y * .

m y, A/,

(25)

T h e added terms are th e values o f th e linear distortion o r h e mage istances y\, \> etc, respectively. T h e values o f y an d /are measured directly. It is evident that th e in - dividual alues f istortion efined n h e preceding quations an e hanged y as- signing o alue ifferent ro m h at given y h e paraxial magnification. After th e araxial magnification nd h e orresponding alues f istortion av e een e-

termined, n adjusted value s used o r th e magnification to distribute th e distortion n a manner es t uited o r h e ntended application. T h i s adjusted value represents th e calibrated magnification, o r CM .

5X2.16 Distortion. AD th e fol lowing methods are apable f measuring distortion n th e lane f best definition with ccuracy, though care should be taken to correlate th e results obtained by methods 28 an d 29 with those btained hotographically. ccurate

determinations f h e istortion t inite magnifications hould e made y ethod 25 r method 0, epending po n h e p- plication. W h e r e ignificant, ystematic r- rors n th e test equipment shall e reduced by aking uplicate eries f measure- roonts fo r each test diameter witn ti e M BS

rotated 18 0 degrees about its optical axis.

5X2.16J ttiutd 5 — Two* ange mstkod. T h i s method s intended rimarily fo r se n eases mounted, n amera« r

cones. Targets shall be se t o p in th e object space is a pleas perpendicular to th e optical axis of th e lens to be tested and, fo r cameras focused o r nfinity, t istance reater than etermined y ormula 12) n S.UL8. T h e targets should h e placed approximately very 2H degrees cross h e entire

field o f th e ens. T h e angular separation o f th e argets hall e etermined o n c- curacy o f ±2 seconds of ar c by means o f a first order theodolite. In some instances, th e distance etween argets nd h e erpen-

dicular istance from th e line o f targets o th e front node f th e lens can e measured and h e ngles omputed. h e ens o e tested hall e oriented with ts front node directly over th e point from which th e range angles are to be turned, its ptical axis i- rected oward h e entral arget, nd ne o f ts diagonals arallel o h e ine f targets. es t late hall e xposed, fter which h e camera r one hall e otated 90 degrees about it s optical axis, and another

test plate shall be exposed. After processing, th e test plates hall be measured on a com- parator. T h e EFL o f th e lens shall be determined in accordance with method 1; th e distortion is determined as specified in .15.8. Curves shall be plotted distortion in millimeters against field angle), representing th e distortion elated to K FL fo r both ides o f th e axis fo r both diagonals. It will usually be found that th e curves fo r th e tw o sides o f a diagonal will o t have qual distortion. By selecting another point, th e "Point o f Sym-

metry," s h e enter f h e ield an d e- computing th e distortion, th e curve fo r each diagonal can be made to be relatively symmetrical h e w o ides f ach- iagonal (four urves n ll) hall e veraged o obtain h e istortion urve. h is distortion curve can e iven ny desired rientation by sing n djusted alue o r h e oca l length th e alibrated ocal ength, ee 5.155). W h e n equired, n ddition o setting up h e en s as specified, h e test plate m ay be adjusted so that it is perpendicular

to h e in e rawn ro m h e entral arget through th e front node o f th e lens. This can be o ne y ointing elescope, quipp*'.' with a Gauss yepMce, long h is in e ud adjusting th e teat ptateeeetiar surface ( with

an optical flat aud th e Gauss •yer'««') nti' It is erpendicular to th e line o f sight he

8/14/2019 Mil Std 150a


addition o f this step enables one to measure prism ngle. W h e n measuring istortion at finite distances th e plane of th e targets must be arallel o h e es t late. Mathematica l means o r adjusting th e measurements m ay

be sed o eliminate error from h is source. If h e istortion s o e measured o r n object t finite istance, th e targets hall be et p t th e equired istance as pecified. h e est rocedure s h e am e s o r th e object at infinity, except that th e istortion s etermined o n h e asis of araxial o r calibrated magnification.

5.1.2.16.2 Method U — CoUtmator ank method. T h i s method is intended for use with lenses mounted either in cameras r in test

barrels. Method 6 s imilar to method 25, except that a bank o f collimators containing targets hall e sed nstead f arget range.

5.1.2.16.3 Method £7 — Single olUmator photographic- method. n o m e ases where high recision s no t equired* a ingle collimator m ay e sed n onjunction with test late s n method 6 . n h is method, either th e co l l imator o r th e lens an d th e test plate hall e - rotated hrough th e equired

field angles about .the center of th e entrance pupil o f th e lens.

5.1.2.16.4 Method 28 — Nodal slide method. This s a visual es t method and m ay be used, when pecified, o r enses mounted n barrels. h e en s to e tested shall be properly laced on th e odal lide f n ptical test ench nd entered o h at ts ptical axis is nearly co incident with th e axis o f th e microscope. Distortion fo r a particular angle shall be measured by th e lateral displacement

of th e observing microscope required to cen- te r h e arget t ac h ngular etting. A t each ngle , h e microscope hal l e isplaced long ts orizontal xis y h e istance (l-cos /3) /cos ß away from h e ens. This refo cusing is no t nec essary if a fiat new

ba r is used. T o obtain th e value o f distortion,

MIL-STD-150A T2 Moy 959

th e lateral distance through which the microscope shall e isplaced must be ivided by th e cosine of the angle at which th e distortion is eing measured. Because f naccuracies present n most optical enches, t is esir-

able to make each measurement at th e same indicated angle on each side o f th e axis and to average th e tw o microscope readings obtained before computing distortion.

5.1.2.16.5 Method £9 — Goniometer method. This is a visual method intended fo r use with enses ounted n ameras. n c- curately calibrated test object on glass, usually n h e form of cale r rid, hall e placed n h e plane o f best definition f th e lens to be tested an d lluminated n a irec-

tion oward th e en s o e tested. h is est object must e lat, roperly entered, nd perpendicular o h e ptical xis. h e lens and illuminated test object shall be placed in th e goniometer so that th e axis about which th e ngles are measured passes through h e center of th e entrance pupil of th e lens. T h e telescope of th e goniometer shall e pointed at uccessive oints n h e es t bject nd th e ield ngles etermined. T h e elescope shall o t e efocused uring h e un h measurements.) ro m h e ocal ength f

th e lens eing ested nd h e calibration f th e est object, h e angles subtended y th e various oints n h e es t bject an e computed. Distortion h en can e omputed in erms f th e ifference n ngles n he object id e nd mage ide; h is istortion in urn an e onverted nto th e standard f orm. See .1.2.3.) y adjusting th e ocus of th e telescope, this method an be expand- ed o nclude o m e ases n which h e est object s n lane orresponding o ome finite magnification. Carp should be exercised

to nsure h at h e one f ight ro m h e test en s s ncluded n h e ntrance unil o f h e telescope.

5.1.2.16.6 Method 0 — Projection method. h is method s ntended rimarily o r testing projection enses. A test object simi-

3 3

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MIUSTD-150A 12 Moy *5*

lar o h e ne sed n method 9 hall e placed n h e bject lane f h e lens o e tested nd rojected nto uitable creen. Measurements shall be made o f th e projected image o f th e test object. T h e distortion hall be computed in terms o f th e test object. Care should e aken o nsure h at h e creen an d es t bject ar e perpendicular o h e optical xis f h e en s nd h at th e est b- ject s la t and roperly entered. h e cone o f l ight from h e projection lamp shall completely ill h e projection ens, nd h e est object hall e niformly lluminated. h e sip» o f distortion is reversed from theory on projection through en s nd measured t th e long conjugate.

5.LU6.7 Tangential distortion. Any of th e six methods fo r measuring radial istortion may e modified o measure angential istortion y .considering h e isplacement f image points ^perpendicular to a radius from th e enter of h e ield. h e agnitude of tangential distortion aries from ero along e r n e diameter to a maximum along an rientation 0 egrees o h e iameter f ero distortion. herefore, h en equired, an - gential distortion hall be measured fo r tw o

axial orientations o f . t h e lens, an d h e orientation r maximum angential istortion computed.

5A2J7 Prism effect.. T o measure th e prism ffect n erms f h in quivalent prism o f vertex ngle a, se is made f th e fac t h at blique ays re eviated y h e prism mor e than, nd in th e same direction as, h e xial ay. An ssumption s made that th e axial ray makes only a mall ngle with th e normal to th e surface o f th e prism

(o r th e rism m ay be assumed to be n h e minimum deviation fo r th e axial ray). If th e camera nder est s sed o hotograph three ollimators r istant argets, one axial nd h e ether wo making ncles ß go d — p with h e xis, h e istances ro m

th e 0 egree mage o h e - J 3 mage nd from h e 0 egree mag* to h e — 0 mage

r

are ifferent n h e resence f rism

effect h is ifference s measured n h e negative Under h e ssumptions made, th e analytical expression fo r this difference is:

A [tan 3 ) — an ß — ) — an .]

(26)

where f s th e equivalent focal ength o f th e lens, s h e eviation f th e ay making ß with h e axis within dose approxima- tion h e eviation s h e am e o r +ß nd —ß), nd , = /2 s th e eviation f th e axial ray. Tables fo r A can be computed fo r various values o f f, ß , an d a. T h e measured an d tabulated values o f A are compared, an d th e orresponding o is evaluated.

5.1.2.18 Spkertcol aberration.

5.1.2.1&1 ethod I — nnual ing r Hartmann disk method. W h e n spherical aberration is specified in terms o f change in focal position fo r zones o f different radii, Hartmann disk a plate covering a front o f th e en s with oles t h e ifferent ones) or aperture consisting of open annular rings will be placed over th e front o f th e lens an d properly centered. Either a photographic r

visual method f determining th e ifference in focal positions fo r dffi«rent zones m ay be used. Various modifications f these meth- o ds nd ther ethods ay e mployed, such s a knife-edge test or interferometric method. W h e n measuring pherical berration o r n bject t nfinity, h e arget which s maged y h e est en s m ay e placed n co liimator r a istance at least 26 imes h e oca l ength of th e en s o e

tested.

5.L2.1&2 Method St — SUrpped-apertvre method. W h e n pherical berration s pecified in terms of th e difference between th e best oc u s t maximum pertUTe nd t designated educed perture, odal lide

. ...» __ „ MtiMif>11ywHnn uulOO optical euen r o MWW««"I «« " * » » - - - — m ay be sed o determine h e ifference n

8/14/2019 Mil Std 150a


these o c a l ositions. A ocusing microscope provided ith cale ndicating istance

along the axis of th e micros cope m ay also be used. The target w h i c h is imaged by th e test lens may be placed either in a coMimator o r at a distance at least 25 times the f oca l length o f

th e lens o be tested. In the atter case h e EFL r BF of he lens s the onjugate b-

ject distance.)

5.1.2.19 Veiling lare.

5.1.2.19.1 Method SS — Photographic black

spot method. Veiling glare m ay be measured by me ans o f an apparatus photograph ing th e test ield s pecified erein. h e est ield shal l onsist of a bright ambert 's aw urface ontaining erfectly lack pot . or

th e urposes of his test, perfectly lack spot ill e ne hose umina nce is no t greater h an 1/109 of the uminance of he bright surface w h e n measured from the position of the lens. T h e black spot shal l e ircular, nd, xcept s oted e low , ts ia - meter ha l l ubtend n ngle of egree ± minutes at the lens under test. For testing lenses of types I, II, III, and V or cone and a mera ssemblies it h hese enses). the bright field shal l be of an infinite extent. T h i s m ay be provided by a large ntegrating

bo x f niform umina nce within n ngle o f 2 steradians. Fo r testing enses of othe r types (or instruments with these lenses) h e bright field shall be limited to th e field to be covered in actual se . T h e spectral distribution of lieht c o m i n g from th e bright field shal l be equal to daylight for types T il and V enses), r m ay be modified y a el - lo w ilter for ypes nd I enses), r e equivalent o he ijrht ro m ource w h i c h is . rray body t 848° (for enses nd instruments ormally sed with ungsten

source). Fo r nstruments w h i c h re no t o r- mally sed with h e ources pecified bove, th e right ield hal l ave pectra l distribution similar o h at f h e o ur c e used with h e nstrument. here hal l e o ubstance ther h an ir etween h e est ield

MIL-STD-1 50A 12 M ay 95 »

and th e lens o r it s attached filter. Fo r testing lenses o r ens-cone nd ens-camera ssemblies) se d to photograph distant objects , th e black po t must e t istance ro m h e lens o t horte r than 10 t imes it s o c a l length . Fo r enses used with elatively s hor t

object distances, th e black spot shall be at th e normally sed istance ro m h e ens. o r testing came ras tha t permit easy focusing o r instruments used with short object distances, th e ma ge of the black po t shall e harply m o c u s n the film or paper) lane of th e came ra r f h e nstrument, espectively.

For esting enses f ens-cone ssemblies w h i c h ave no focusing mechanism, h e est apparatus hal l e rovided with movable film older or ha rp ocusing of the mage

of the lack spol f the o c a l ength of h e lens s o o hort o roduce an mage of t least millimeter iameter ith h e -degree lack pot , he lack pot shal l e n-

creased n ize o hat he iameter of ts image e c o m e s pproximate ly , ut o t ess than, millimeter. In lens-camera assemblies focused or nfinity and having no ocusing adjustment, the image of the black spot will be necessarily out of focus in the f o ca l plane of the amera . h e mage will ave ark

center whe re there re no ut-of- focus ays

from the right ield, rovided that th e diameter of he lack po t s reater h an the aperture of he en s nder est h e - degree black spot hal l e at such e istance from h e en s that th e diameter of th e ar k center of th e out -o f - f ocus mage shal l be ap - proximately, ut no t less t ha n , millimeter. T h e equired istance ecomes nfinity for a lens of 57A m m o c a l length an d t still m ay be oo great o r ractical nstrumentat ion with lenses of s o m e w h a t longer focal lengths. For enses of f o c a l ength« horter t ha n 57.3

m m , h e equirement of millinict'-r mage diameter a n n o t e m et it h h e -degr»e spot at any ea l istance. In these ases, th e

black spot shall h e ncreased in lire an d placed at uc h istance h at h e iameter of he dark center of th e otrt-of-focus ma ge

35

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MIL-STD-150A 1 2 May 95»

»hall e pproximately, ut not less than, millimeter, nd he outside diameter f the out-of-focus image shall be not greater than 2 millimeters. When th e -degree black spot is used, measurements shall be made of the illuminance n the dark center of the mage of he lack pot an d of the illuminance n the mage of th e bright field at 1 egree 30 minutes from the center. In th e cases where a larger black spot must be used, the illuminance of th e mage of the bright ield hall be measured at 1.5 millimeters from th e center of th e image of the black spot. In either case he alue f he lluminance f he

image f the bright field hall e he mean of two measurements aken at th e pecified distance n he pposite ides f he dark

image. hotographs of the test field shall be made n he mulsion o e se d with he instrument Light cattered ac k nto he instrument y he mulsion an ontribute significantly o eiling lare. ence, ny test method must provide a reflecting surface similar to the unexposed emulsion over prac- tically the entire film plane.) Measurements shall be made at full aperture, an d an y other

aperture pecified, with he lack po t n axis an d at other positions in the field of th e instrument, including positions near th e

edges nd orners f he ield. ny rea which ay e ffected y eflections ro m asymmetrical tructures etween the bject

plane an d the film plane shall be investigated. T he percent veiling glare shall be calculated fo r each position in th e field, an d variations of eiling lare with osition n he ieW shall e resented n able r raph or

each perture tested. Any significant asym- metries hall e ecorded. well-controlled method of photographic photometry shall be used to btain he atio f the lluminances of the mage of the black spot an d th e adjacent mage f he right ield. ne f he methods is to use a density step-wedge. This shall be placed ve r the mage of the bright

field ndin^nt to th e imaee of the black spot, an d hotograph f he est ield hall e

r

taken. Densitometric readings shall be made on he mage f the black spot an d n he images of th e tw o steps which produced the nearest higher and ower densities than the density f he mage of he black spot y interpolation, he ensity ecessary n he

step-wedge o roduce he ensity f he image of the black spot shall be found. This density f he tep-wedge s qual o he logarithm of the ratio of illuminances of the bright urround Et) nd f he mage f the lack po t Ef). he eiling lare s

then computed as:

E. V = 00

E, (27)

5.1.2.19.2 Method Si — Photooraphu: black strip method. T he pparatus nd procedure used in this method are the same as in method 3, xcept that black strip s se d n- stead of a black spot T he limitations imposed on the width an d distance of the black strip are the same as specified for th e diameter of the black spot T he length of the strip shall subtend at the lens the maximum total angle to be covered by the lens in actual use. Meas- urements shall e made along th e mage f th e black strip t various distances ff axis up o he maximum ngle overed y he lens to find the distribution of veiling glare across the field. In th e case when an out-of- focus image of th e black strip must be used for testing, some out-of-focus rays from the bright field will ass through ertain reas at the ends of th e mage of the black strip. T he xtent f hese reas hall e etermined, nd he y shall not be used for meas-

urements.

5.1.2.19.3 ethod 5 hotoelectric

method. This method se s th e same pparatus of methods nd 6 , except that a light- sensitive measuring device of spectral sensi- tivity haracteristics imilar to those of the sensitive hotographic aterial, hich s normally used with he tens under test, shall

3«

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be se d n he mage lane f he est p- paratus.

5.1.2.20 ondenser performance. he on - denser shall be set u p to simulate the equipment in which it is to be used, an d th e image

of a designated format shall be projected on a creen. he niformity f creen lluminance an d otal ight utput shall e measured with oot-candle meter nd hall e as esignated for the particular application.

5.1.2.21 eauty efects. he n nspecting for scratches an d digs, a reference standard glass ontaining raded cratches nd igs used s uide hall e sed. he cceptance tandards n ll eauty efects hall be determined by the individual application.

5.1 .222 Centration. When inspecting lenses or errors in centration, compliance with th e equirements n esolving ower, angential istortion, nd rism ffect shall e of primary consideration. T he lens examined should be tested across a field diagonal which gives the lowest resolution or maximum tangential distortion, whichever is th e most im - portant onsidering he se or hich he lens s ntended. outine nspection, ased on ff-axis tar mages, m ay be ubstituted

for hotographic ethods he n roperly correlated.

Copies f peci f i cat ion , tandards, rawing*, nd publications equired y o n t r a c t o r s n onnect ion with pecific rocurement unctions h o u ld e b- tained rom he rocuring ctivity r s irected by ontracting fficer.

Copies f his tandard or military se may e obtained n he foreword o h e ndex f Military

Specifications nd tandards. Copies of this standard may be btained or ther

than fficial se y ndividuals, ims, nd ontrac-

tors ro m he uperintendent of Documents , . . Go ve r n m e n t rinting ffice, Washington 5, . .

iwings, specif otice. W h e n Government drawings, specifications, or ther ata re se d or ny urpose other han in onnect ion ith efinitely elated o ve r n m e n t procurement peration, h e nited tates overnment hereby ncurs o esponsibility nor any bli- gation hatsoever; nd he act hat he overn- m e n t ay ave ormulated, urnished, r ny way supplied he aid rawings, peci f i cat ions , r ther

data s not o e egarded by mplicat ion r therwise s n ny manner icensing h e o lder r ny other person r orporat ion , r conveying ny ights o r permission o manufacture, se , r el l ny a- tented nvention hat may n ny ay e elated thereto .

Preparing ctivity: Air Force

O t he r nterest: International

Other ustodians:

Army—Signal orps Navy—Bureau f Aeronautics

J

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M&-STD-150A » May *5 9

rAPPENDIX

10. REFERENCE MATERIAL

10.1 E N E R A L . h e material overed n this ppendix o es o t o rm art of his

standard. It is provided, primarily, as reference materia l o r assistance n th e rocure- me nt and nspection of photographic enses. Suggestions concern ing requirements related to o m e echanical etails nd ther ea - tures are given. A reference list intended fo r use y h o s e reparing pecifications nd procurement ocuments s ls o rovided.

10.2 ENS OUNTI NG , ND THER

R E Q U I R E M E N T S .

10.2J Mounted in a ceü. W h e n pecifying members mounted n el l o r multiple cell en s usuaUy wo ells, ron t an d ear) ♦ . h e ollowing details hou ld e specified:

a. Cell separation r th e correc t should- er-to-«houlder mount ing distance (sometimes alled barrel ength) should be supplied with each lens by th e manufacturer .

b. Dimensions and etails o f th e cells.

c . Dimensions and etails o f th e mo unt - in g parts threads , tc.) .

10.2.2 Mounted n a arrel. W h e n specify- in g a lens mounted n a barrel h e ol lowing details hould e specified:

a. Length of th e threaded ortion of the barrel.

b. W h e t h e r barrel shall be furnished with a threaded ring. If threaded ring s equired, imens ions nd

details such as mount ing ho les o r means f ecurely etting t ny posit ion long h e hreaded o r- t ion of th e barrel.

c. W h e th e r barrel shall be provided with a fixed lange. f ange s mjmr-

ed , imens ions nd etails uc h as mount ing holes .

10.2.3 Mounted m a »hotter. W h e n specify-

in g en s mounted n hutter h e o l l owing details should be specified:

a. Requirements of hutter speeds, f- fic iency, etc).

b. M et ho d s of attaching shutter to camera.

c Dimensions and details f shutter.

d. hreads if equired) o r t tach ing

lens o hutter nd hutter o camera.

e. pecial hutter eatures (self-timer, sychronizer , etc).

10.2.4 Mounted in cone. W h e n equired, a lens, m ay be mounted in a lens cone . W h e n required, h e ollowing etails hould » e

specified :* '

a. etails nd imens ions of h e one- camera eating urface .

b. Distance f rom one-camera sealing surface o o c a l lane.

c. ocusing mea ns within he one.

d. Mechanical etails and imens ions o f th e cone dapter.3*

e. A ny additional mechanical details an d dimensions deemed ecessary.

10.2.5 Mounted in a focusing mount. W h e n specifying en s ounted n ocus ing mo unt h e ollowing etails hould e pe -

cified Ir v K o - r wi n h i ch ho mi urf»r» f h * »* »d

focml lane ninrtda for ample, rtorraphic liwrul. e- 1*11. wntnuni luchmnt r h « w > amera houlJ » ur-pliorf

* o n * 4al>Wr i ef lnod * etarhabW an »f k. on. irh.rh ar nnlnxl > ioiiai o r win h » o n» n -' - feront ea»Btr*fl

3 f c

8/14/2019 Mil Std 150a


a. lange ocal istance ee e .1.7).

b. Range of focus an d accuracy of scale.

(See C in 4.15.3 .)

c. Whether r not he ens may otate when focusing.

d. Whether or not the lens may focus by separation of th e members.

e. Method nd etails oncerning he mounting of th e focusing posts.

f. Dimensions an d details of the mount-

in g surface.

g. ther mechanical etails nd imensions deemed necessary.

10.2.6 Diaphragm.. When specifying a lens

which is mounted in a barrel, in a cone, in a focusing mount r hutter, hich equires a diaphragm, the following details should be

specified:

a. ype f iaphragm (iris r ther, nu mber of leaves, etc.).

b. Dimensions an d etails.

c. ype f marking an d calibration f- stop, T-stop, perture atio).

d. elated features (click stops, ia-

phragm ontrol n the orm f ring ear or emote ontrol. total ngular ravel nd ngle corresponding to each stop marking, limit stop to prevent closing to oo mall n perture, tc.).

10.2.7 Statistical data nd quality ontrol. When required, t may e specified that he contractor shall supply to he rocuring c- tivity, etailed ecord f he tatistical facts oncerning pecified ttributes nd

variables. hese uality ecords hould n- clude ot izes, ampling ize, cceptable Quality evels, cceptance nd ejection numbers , ncidence of efectives, nd ther pertinent data such as quality control cherts on ttributes nd ariables ffecting inal

M1L-STD-150A II May Wf

performance nd nstallation. When equired , he classification of defects should e as specified. ampling equirements hould e

clearly stated in the specification or procurement document an d should be n ccordance with MIL-STD-105.

10.2.8 umber f enses o e estroyed. T he pecification r rocurement ocument should learly tate he umber r ercent of a given order to be given an y destructive

tests.

10.2.9 ackaging. etail ackaging e- quirements should consider the type an d size of lens to be packaged as well as its intended destination.

10.2.10 M arkings. Details oncerning he extent to which a lens should be marked an d th e manner of marking th e packages should be iven n he pecification r ther rocurement ocument.

10.3 RDERING AT A E F E R E N C E LIST.

10.3.1 eference list. When preparing specifications r ther rocurement documents, th e ollowing eference is t hould e sed. T he irst our tems re dentification e- quirements which govern, in general, the na- ture f he ens nd rovide imited e- scription. he remaining items concern performance haracteristics, hysical nd me - chanical eature«, arkings, esting, nd packaging. "R" nder a particular lens type signifies hat equirements concerning his feature re equired o e pecified. O "

signifies that consideration of this feature is optional. A" ignifies hat dditional echnical details are required in the specification to make roper use of this feature. X im- plies that this item s not usually applicable

to the lens.

8»

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M0-STD-150A 12 May 9S 9

r n m rr T Y X T O in zi z xi m xm xxr

Type required an d ne e (Sail*) BBBBBBBBBBBBBB

Equivalent f o ca l length ««„»»(See SX4 « m d 4X6) BBBBBBBBBBBBBB

HaxinH^m relative aperture or T-etop See 4XS) EBRBBBEBBEBRBE

Field f view See Si) EBBBBBEEEBBBBBConatroetion o f len» See SJ) 00 0 0 0 00 00 0 0 0 0

Calibrated o c a l ength i (SeeSXE) 0 0 0 O A 0 O A OA OA X X X OA OA 0

Back oca l #ft,w» * (See X« ) 00000000000000Flange f o ca l istance (See SX7 nd .4.6) ER00RO0OOX00

Front oca l istanoe (See8X8) OOOOOOOOOOXOOOFront ertex ac k o ca l i»-

(8oe8X») 00000000000000

r

Front perating' pertsre (SM 8i7) 0000000000X00

Bear operating aperture (SMS.1I) OOOOOOOOOOXOOO

B a t o M n r power Sea Mi) BBRBBBBEABBXRBE

Ana weighted venge O- notation SMtiii) EBR0R0O0XXR0E

Astigmatism and eurmtara o f field See 8^8) .... OOOOOOOOOOXOOR

Color correction SM .«\4) BREBBBBBBOOBRRRadial latwrtlii So * 8.M

an d 8.8.0) 0 R 0 R O O O 0 O 0 X 0 0 0 Tangential istortion

(See .& 6 J K ) 0 R 0 0 0

Priam effect See l&JUB) ... O 0 0 Relative Dhmination

(See » A T ) E R R R R

Trananhtance See 8.6.») .. 0 0 0 0 0 Area weighted average

Tamrtsr See S.6JL) ... 0 0 0 O 0 Spberieal berration

(See*.«).... 0 0 0 0 0 Other berratione 0 0 0 0 0

Vemnrftoe «M«A10) .. 0 0 0 O O

(flee X21 ) Mounting .................

Maphragn nqeii—is (See 1X4 nd 10X8) ,...

W aterhoase top* See 8X4)

Leva Marking Be e 4X1) . Intermediate aperto» nuking

(8t* lAI) 0000000000

40

0 X 0 X X X 0 0 0

o X 0 X X X 0 0 0

BA BA BA 0 0 X BA B B

0 0 0 0 0 0 0 0 B

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

O 0 0 0 0 X 0 0 0

X X X X X B X X X

B B B B B B R B B

E 0 0 R X X B R B

0 X X X X X 0 0 0

B E B E B B B B B

8/14/2019 Mil Std 150a


MH-STTM50A 12 May 9S9

i n in IT v n ra vm xt x xi xn xm xtr Accuracy of focusing scale*

(when equired) (See UU) RA X BA £A EA OA X X XX X EA BA 0

Reflection reducing oat ings (See .7.2) BBEBBBBBBBBBBE

Beauty defect* See .8 ) E EE E E E E E EE E E E E

Environment»]

See XS) ..£

EE E E E E £ EE E E E R Finish nd internal urface* (See 8.7.5) E EE E E E E E EE E E E E

W h e r e nspected EEEEEEEEEEEEEESampling plan E EE E E E E E EE E E E E Statistical data required

(See 0X7) EEEE EEEEEEEEEBW h a t ndividual 00 ercent

»•*» See .1 ) EEEEEEEEEEEEEEW h a t ampling ests (See

10i8) EEEE RBBBRRBBBBFQms nd rocessing See

6XL8 nd .1X12.1) EEEEEEXEBXXEBEPlane of best definition

(SsefiXXl) EEEEBXEEEXXEEE

Method of m ea su ring quivalent- ecal ength (See ^1^2) EEEEEEEEBE

Method f m easu ring ffective aperture See 6XZ») EEEE EEEE BO

Method f- measuring -number nd ransmittanee See SX2JO) ooooooooox

Method of measuring elative illumination (See .1X11) K RR R R RARARAOO

Method of measuring resolving power See 5X2J2) ERRRREBRRR

Target istance (See .l.O) OOOO0OOTarget ontrast nd hether dark ines n ight ackground r ic e erse (See V*) EEEEEEBERRXRRR

W hether en s s o e e-ted with ilter n lace r v«x l ight source Sec 5X1.4) .. RRBRBBRRRRXRRR

Relative aperture fo r resolving power tost See 5.1.2.12) BERREEBRREXEEE

Angular settings fo r resolving« power images See 6.1X12) RREBEEBEREXEEE

Magnification or eading e- solving power See 6.1X12) BRRRRBBRRRXRRR

Method of measuring astigmatism nd urvature of ield (See6X2J8) 0000000000X00

Method f measuring hro - matic berration* Sa *

oooo

41

R R R R

X R R R

X 0 0 0

X RA R R

X R R R

X 0 0 R

8/14/2019 Mil Std 150a


MIL-SUM 5Q A 12 May 9S 9

i

Method of measuring istor-

tion Sec . 1 . 2 .16)

Method f measuring spherical

aberration See .1.2 .18) .. Method f measuring eiling

glare (See .1.2.19)

Method of measuring eauty defects See 5J.Ü1)

Environmental ests

Preservation

Unit ackaging

Exterior packing Cushioning

Overseas acking Domestic acking Package marking H in

R

VI

0 0

VII VHI XI

0 0

xi xii xiii r.iv

0

R R R R R R R R R R R R R

R R R R R R R R R R R R R r . R R R R R R R R R R R R R R R R R R R R R R R R R

R R R R R R R R R R R R R I : R R R R R R R R R R R R P . R R R R R R R R R R R R P . R R R R R R R R R R R R R R R R R R R R R R R R R

r

10.4 REFERENCES.

10.4.1 is t f nonmandatory eference». T h e fol lowing lists are fo r information only, an d re o t o e onsidered pplicable o this standard in an y other sense. These documents will no t be supplied y th e procuring activity.

10.4.1J merican Standard* Association.

PHS.10-1954 Threads o r ttach- in g Mounted ens-

es o hotographic Equipment

PHS.12-1953

PH8.14-1944

— Attachment Threads fo r en s ccessor- ies, pecifications for.

— Front Lens Mounts fo r ameras, i- mensions f.

PH8.16-1947 — Resolving ower f

Lenses o r rojectors o r 6-mm Slide Film nd x 2-Inch Slides, Meth- od o r etermining.

PHS.20-1955

PHS.25-1M8

Z22.28-1946 —

PH22.5S-195S

Focusing amera Lenses, istance Sealee for.

Parts f hotographic bjective Lens, Nomenclature for.

Projection Rooms an d Lenses o r Motion Picture heaters,

Dimensions for. Method f Determin-

in g Resolving Pow- er f 6-mm o- tion-Picture Projec- to r Lenses.

PH22.76-1951 —Mounting hreads an d lange ocal Distances fo r Lens- es on 6-MflHmeter an d -Mill imeter Motion Picture Ca- meras.

PH22.90-196S Motion-Picture enses, perture alibration o f.

4 2

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Z38 .4 .4 -1942

Z38.4 .7-1950

Z38 .4 .20-1948

Z38 .4 .21-1948

Z38.7.5-1948

Focal engths f

Lenses , Marking.

Lens Aperture Mark-

ings.

Apertures nd Relat- ed uantities er-

taining o hotographic enses, Methods f Desig-

nating and Measur-

ing.

Focal engths nd Focal Distances f Photographic Lens-

es , Methods of Des-

ignating nd Meas- uring.

• Printing nd rojection quipment, Methods of Testing.

ZS8.7.6 .-1950 Photographic Enlarg- ers. ethods or Testing.

10.4.1.2 National Bureau of Standards. Precision Camera for Testing Lenses, I. C.

Gardner and . A. ase. . Research N.B.S.

18 , 4 49 1 937 ) RP 984 .

Resolving Power nd Distortion f Typi- cal amera enses, . . Washer, . e-

search N.B.S. 2 , 2 9 (1939) RP 2 1 6 .

Locating he Principal Point f Precision

Airplane Mapping Camera, . . Washer, J. Research N.B.S. 7. 05 1941) RP 4 2 8 .

Measurement f the Refractive ndex nd

Dispersion f ptical lass or Control f

Product, L L. Guruvitz nd . W . Tilton. .

Research N.B.S. 2 , 9 1 9 4 4 ) RP 572 .

Region f sable magery n irplane- Camera enses. . . Washer. . Research

Refractive ndex tandards f luocrown

M1USTD-150A n to y W

Glass, . W . ilton, . Research N.B.S. 4 ,

59 9 1945) RP1659.

Compensation of the Aperture Ratio Mark-

ings of a Photographic Lens for Absorption,

Reflection, and Vignetting Losses, L C. Gard- ner, . Research N.B.S. 8 , 43 1947) P

1803.

Validity f he Cosine-Fourth-Power L aw

of llumination, . . Gardner, . Research

N.B.S. 39 , 2 13 1 94 7 ) RP 1824 .

Sources of Error in and Calibration of the

F-number f hotographic enses , . .

Washer, . Research N.B.S. 1 1948) P 1927.

Research and Development in Allied Optics and Optical Glass at the National Bureau of Standards, iscellaneous ublication 94 , July 949, by . C. Gardner and C. H . Hah-

ner.

An Instrument for Measuring Longitudin- al pherical berration f enses, . . Washer, . Research .B .S . 3 1949) P

2015.

Calibration of Precision Airplane Mapping Camera, F. E. Washer and . A. Case, J. R e-

search N.B.S. 5, 1950) RP 2108.

Method or etermining he esolving

Power of Photographic enses, F. E. Wash-

er, nd . . Gardner, N.B .S . Circular 33,

M ay 953. upplement o .B .S . ircular

533, wo sheets of test charts.

Sources f Error n Various Methods f

Airplane Camera Calibration. . . Wash-

er, N.B.S. Report 2 5 3 4 , une 1953.

Optical mage Evaluation, N.B .S . Circular

5 2 6 , 9 April 954.

A tudy of mage Contrast as a unction

of requency t hree bject ontrast Levels or Nine Wide Angle enses. . W .

F.osborry. NFS Report *0*. ec * > * 4

A Simplified Method of Locating the Point

i?,

8/14/2019 Mil Std 150a


MII-STD-150A 1 2 May 959 o f Symmetry, F. E. Washer, N.B.S. Report 4273, August 1955.

Evaluation f Distortion y h e nverse Nodal lide, . E. Washer, N.B.S. eport 4690, M ay 956.

Effect o f Camera Tipping on th e Locat ion o f h e rincipal oint, . . asher, . Research N.B.S. 7 1956) P 691.

10.4.1.3 Journal o f th e Optical ociety f America.

Effects f emperature nd ressure n th e Focus o f Aerial Cameras, E. B. W o o d - ford nd . . ierenberg, 5, 19 O ct 1945).

Effective Aperture o f a Photographic Ob- jective, R. Kingslake, 55, 18 A ng 45).

Proposed ethod f pecifying Appear- ance Defects o f Optical Parts, J. H . McLeod an d W . T . Sherwood, 35, 36 Fe b 45).

T h e easurement f ransmission nd Contrast n ptical nstruments, . . McRae, S3 , 29 Apr 43).

Illumination n h e Focal Plane, F. Ben- ford, 3 1 , 6 2, M ay 1).

A lassification f hotographic en s Types, R, Kingslake, 3 6, 251 M ay 46).

Autocollimator fo r Precise Measurements o f h e lange ocal istance f hoto - graphic enses, M . . ownsley nd . . Foote, S7 , 42 Jan 47).

A Method fo r Making Precise Resolution Measurements, . . oleman nd . . Harding, 3 7 , 26 3 Apr 47).

Illumination

n h e

ocal

lane f

Camera Lens, P. Clancy, 37 , 906 NO T 47).

Lens esign nd olerance nalysis Methods an d Results, P. . Foote and . A . Woodson, 3 8, 590 Jul48).

Notes n h e os4 aw f llumination,

M. Reiss. S, 30 No v 8).

Method f Measuring h e Contrast Ren- dition o f Telescopic Systems, H. S. Coleman, G. W . Arnold, Jr., an d W . 0. Luedecke, 3 9 ,

86 4 O ct 49).

Photogrammetric rrors rom amera Lens Decentering, . . arman, 9 , 51 (Dec 49).

Brightness f Fine Detail n Air Photo- graphy, P. D. Carman an d RA..F. Carruth- ers, 41 , 305 M ay 51).

New Resolving f ower est Chart, F. E. Washer an d F. Roseberry, 1 , 97 Dec 49).

Spurious esolution f hotographic

Lenses, R. HotcbJrias, F. E. Washer, an d F. Roseberry, 41 , 6 00 Sep 51).

A Collimator with Variable Focal Length an d ilted Test Plate fo r Testing Cameras. P. J. Lindberg, 41 , 74 8 O ct 52).

Lens esting ench, . eistner, . Marcus, an d B. W . Wheeler, Jr., 43 , 44 Ja n 53).

On th e Flare o f Lenses, G . Kuwabara, 43 ,

53 Ja n 53).

A ir hotography, D. . MacDonald, 3 , 290 Apr 53).

T h e elative hotographic fficiency f Certain ight ources, R. N. Wolfe an d F. H. Milligan, 43, 791 Sep 53).

Studies in th e Resolving Power o f Photo- graphic Emulsions, F. H. Perrin nd . H. Altman:

I h e esign n<TPerformance f an Apochromatic Resolving-Power Camera bjective, . . errin an d H . 0. Hcadley, 3 8, 040 Dec 48).

II ie Resolving ower Cameras n th e odak esearch aboratory. il. 26 5 Apr 1).

I T T T h e ffect f h e elative per-

44

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tare f he amera ens n he Measured alue, l, 03 8 D ec

61).

IV he ffect f evelopment im e

an d eveloper omposition, , 46 5 Jul 6 2 ) .

V T he ffect f eduction nd n- tensification, 1 2 , 46 2 Jul 62).

V I he ffect f he ype attern an d he uminance Ratio n he Test Object, U S , T O O Sep 53).

Condition f qual rradiance nd he Distribution of Light in mages ormed by Optical ystems without Artificial ignet-

ting, F. Wachendorf, U S ,

12 05

D ec 53). Problem f valuating White ight

Image, . E. Hopkins, Susanna xley, an d J. Eyer, U, 92 S ep 54).

Variation n istortion with Magnifica- tion, A. A. Magül, U S , 14 8 Mar 56).

Photographic Resolving Power an d Aber- rations f enses, . Murcott nd . . Gottifried, 46 , 434 Jim 55).

Theory of he ntegrating phere, . A. Jaoquez nd . . uppenheim, S , 6 0

(Jun 5).

Resolving ower f hotographic mul- sions, . Hariharan, 6 , 315 M ay 56) .

Studies f he mage Formed by Lenses, t» . -Kvw&bara:

I n the Characteristics of an Image an d Their Quantitative Representa- tion, 4S, 309 Apr 56).

II T he Effect of Spherical Aberration Optical Images, US, 6 2 5 Au g 56).

10.4,1.4 hetogramroetric ngineering.

T he Interpretation an d Uses of Lens Tests an d amera Calibration, . . Gardner, III. 13 Mar 87).

T he ignificance f he alibrated ocal

MIUSTD-150A T 2 May tjf

Length, I. C. Gardner, X , 2 2 M ar 4 4 ) .

T he alibration f ir ameras n Canada, R. H . Field, XII, 14 2 Jon 46).

AM C esearch on Resolution nd Distor-

tion, P. L. Pryor, XII, 388 , D ec 46).

Resolving Power f Photographic Lenses, K. Pestrecov, X J H , 6 4 M ar 47).

Tangential istortion nd ts ffect n Photographic xtension f ontrol, . . Pennington, XIII, 35 , M ar 7).

Field amera Calibration, . . Merritt, XTV, 303 Jun 48).

Report of ommission I, hotography, to the ixth nternational hotogrammetry

Congress, IV , 2 9 1948) .

Field alibration f erial apping Cameras, . . ewell, XIV, 36 3 S ep 4 8 ) .

Resolution, Distortion nd alibration f Air Survey Equipment, L E . Howlett, XVI, 41 M ar 50).

Calibration f recision irplane Map- ping Cameras, F. E . Washer an d F. A. Case, X V I , 502 S ep 50).

T he Fairchild recision amera alibra-

tor, C. L . Norton, X V I , 6 8 8 Dec 50). Illuminance n he ocal lane of Aerial

Cameras, P. A. Täte, X VII , 19 Mar 51).

Calibration f urvey ameras nd Lens Testing, D. . MacDonald, VII, 83 Jun 51).

Methods f ield amera alibration, . L. Merrit, VTI, 10 S ep 1) nd XVin, 6 55 S ep 52).

T he ffect f arget ontrast n he

Focus nd erformance f he Metrogon Lens, H. A. W . McGee, X VIII , 8 48 D ec 52) .

Distortion — lanigon Versus Metrogon, E . . Sewell, X X , 6 4 M ar 54).

Differences etween isual nd hotographic Calibration of Air Survey Cameras,

45

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MIU-STD-1 50A

12 M ay W

P. . arman nd . r o w n , XII, 28 (Sep 56).

A ew oo k t en s istortion, . . Lewis , XXII, 6 6 Sep 56).

Source s of Error n arious M e t h o d s of Airplane Camera Calibration, F. E. W a sh e r , XXII, 27 Sep 56).

10.4.1.5 ournal f h e ociety of M o t io n Picture an d Television Engineers.

Technique or esting hotograph i c Lenses N o v 88).

Report of h e M P T E ubcommit t ee n Lens Calibration, 5, 6 8 O c t 49).

Diffuse an d CoHimated -numbers. A Re-

view nd escription f ew quipment , A . E. Murray, 56 , 79 Ja n 51).

Image Gradat ion , Graininess nd ha rp- ness, n Television nd Mot i on Picture ystems, O . H . Scha de , 58, 81 M ar 52).

10.4.1.6 Photogrammetria .

Distortion Principal Point , Point of ym - metry nd alibrated rincipal oint . . Roelofs , I 1950-1961).

Report f nternat ional ommis s ion —

Proposal o r nternational h o t o g r a m - metric en s Tests, II 1950-1951).

A New M et ho d or h e Determinat ion of the istortion nd nner rientation n Cameras nd rojectors , . allert I (1954-1955).

10.4.1.7 Proceedings Phys ica l ocie ty .

T h e easurement f berrations July

1944).

T h e erformance f ircraft amera

Lenses, W H elwyn. an d . . earle, LVin, 93 1946).

10.4.1.8 Pho t o Technique .

Lena — Emuls ion e rf ormance — R. . Williams,*. 0 Nov 1940).

Measuring the Resolving Powe r of Lenses,

C. . endall nd . . c humac her , ,

(April 1941).

10.4.1.9 Microtenic .

Standardizat ion of h e Test Meth ods o r

Photogramoaetr ic bjectives — H . Rasper, III, No . 5 1949).

10.4.L10 Photogra phic Journal .

Accura cy of th e Image, . . Tearle, 7B , 182 Nov.-Decl947).

T h e hotograph i c nd isual esolving Powe r of enses, E. W . H . elwyn, 8B,

and 6 Jan.-Feb. an d May-June 1948).

Criteria f mage -Forming uality n

Photogra phic

bjectives

—

.

einstein, 9lB, 88 1951).

10.4.1.11 Photograph i c Engineering.

Le ns peed as imit , . W . Kendal l , Vol , 5 1953).

Comput ing h e rea eighted verage Resolut ion f hotograph i c enses — . Leistner, Vol i, 6 2 1963).

A Study of th e nformation Capacit ies f a Variety of Emulsion ystems, R. A . K a r -

das, V o l , 90 1955). 10.4.1.12 Department f Defense Publica-

tions.

10.4.1.12.1 Department of h e Navy.

Photogra phic nterpretation Center:

Introduct ion o amera Calibration—Re- port No . 27-50.

Goniometer ethod f amera alibra- brat ion—Report No. 28-50.

Coll imat ing amera ethod f amera Calibrat ion—Report No . 29-50.

Photograph i c Goniometer Meth od of

Camer a Calibrat ion—Report No . 80-50.

Star Exposure Meth od of Camera Calibra- t i on—Re port No . 81-50.

4«

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Terrestrical Exposure Method f Camera Calibration—Report No . 82-60.

10.4.1.12-2 Department o f th e Army.

Tangential istortion, R. . ivingston,

Engineering esearch nd evelopment Laboratory Report 21 9 No v 951).

10.4.1.12^ Department f h e A ir orce .

Photographic Lens Testing, R. N. Nieren- berg, A ir Material Command M . R, No . Eng. —59-841-413-16 M ay 4).

10.4.1.13 Books.

Summary echnical eport f DRC (OSRD) Division 6 , Volume 1, Optical In - struments.

M & - S T I M 5 0 A 12 M ay 1W

Method e Control, Congress Internation- al de Photogrammefcrie UH aye , 1948, Paris Institute Geographique National

r> uti«n tandards Association Z7.0.4.1 —1951, pecification o r tandard ethod

of Determining Veiling Glare n Photogra- phic Systems.

Photo-Electricity, V. K . Zworykin nd E. G. Ramberg, John Willey & Sons, Inc. 1949.

M inimi f hotogrammetry, merican Society f hotogrammetry, George Banta Publishing Co., 952.

Physical Aspects f Air hotography, G. C. Brock, Logmans, Green and Col, 1952.

T h e Theory o f th e Photographic Process, C. E. Mees, T h e Macmillan Co., 1954.

47

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MIL-STD-150A 1 7 . May 959 r

INDEX

A M » > umber. .7.412 Al«rration, ateral hromatic, .6 .4.2 , 5.1.2.141

lowrHoo ' ina l hromatic, -6.4.1. .1.2.14.1 sphorv-al , .6.:>, .2.1 R

Ac hr o mi U , .7.1.1 Air bells, .R.1.1.2 Anastigmnt, .7.1.2 Angles, obliquity, .6.7.4 Annular ring o r Hartmann isk me t ho d or measur-

in g pherica l berration .1.2.18.1 Aperture, lear, .2.4

am i elated quantities. 3.2 effective, .2.3. .1.2.9 front operating, .2.7 marking:, 4X3 m a x im um , .1.3 numerica l n d orresponding -number , EXJl ratio, 312, .1.2.8rear operating. 3.2.8 relative, .2.5 stopped-, ethod , or measuring pherical ber-

ration, .1.2.18.2 A p o c h r o m a t , .7.1.3 Apparatus, est, .1.1 Area weighted verage esolution AWAR), .6.2.5 Area weighted verage -number (AWAT) 316.1 Astigmatism nd urvature of ield, .6 .3 AutoeoUimat ion , rincipal o in t f, .6 .6 .4 Axis, mechanical, .1.3

of best definition, 3.15 optical, .1.1

Axes, oints nd distances, .1 B

B a ck ocal distance, .1 .6 , .1.2.4 Barrel. .4.2, 0.2.2 Beam ections, .6 .7.3 Beauty defects, .8 Bells, ir, .8.1.1.2 B e n ch , ptical, .1.1.2 Best verage definition ver h e icture rea, lane

of BADOPA), .1.2.1.1 Best efinition, lane f .1.2.1, .1.2.1 Birefringence, .7.4.3 Blisters, .8.2.1 Brilliance, pecific , .6 .10 Bubbles, .8.1.1 Burns, .8.2.2

Calibrated ocal ength, .1.5. .J.2.3 Cell, .4.1. 0.2.1 Omment tart», .8.2.3. Centrat ion , rrors of, .6 .6 .3

Chips, 3.814 C h r o m a t i c berration, ateral, .6.41 .11141

longitudinal, .6.4.1, .1114.1 Coatings, eflection educing, .7.2

Col l imator , .1.1.1 m e t h o d s . ethod 6 , -number an d transmittance

measurement* , EX2J0J

Method 8, elative iUnmination measurements, 6.1111.2

Method 1, esolving ower easurements, 6X112.1.1

ethod 6 , ollimator bank distortion measurements , .1.2.16.2

Method 7, ingle co l l imator distortion measurements , J116J

Co l o r ontr ibut ion , .6.8.1 Co l o r orrect ion , .6 .4 , 5.1114 Combinat ion m et h od or measuring quivalent ocal

length, 6.11211 C o m po n e n t , .3.3 Concentration, osition f reatest, .6.9.1.1 Condenser erformance , .1.2.20

characteristics, .6 .11 Condit ion est, .116 C o n e , .4.3, 1014

adapteT, 0.2.4 Constructional eatures, .3 Contrast, arget, o w , 5.1.113

m e d ium . 5.1.1.72 high, .1.1.7.1 rendition, .6 .10

Cords , 3.8.1.85 C o s * aw, 3.6.75

Cracks, 3.816 Curvature of ield nd stigmatism, 6.1113

Defects, material, .8.1 manufacturing, .8.2

Definition, lane f est. .1.2.1, .111 over the p>rture area, plane of best average

(BADOPA), .1.2.1.) Densitometric method, or measuring relative l lumi-

nation. .1111.3 Depth of o c u s nd depth of ield, .1.11 Design, am e of, .3.7 Diaphragm, ens, .4.4

marking f, 4Mspecifying , 0.2.6

Digs, .8.2.6 Dirt, 3.817 Dirt oles, .8.2.6.1 Disperrion, .7.4.2 DispTy'vf owfr . .7 4.2.1 i "ItSltCf * r » c k Ifrr.l, 1.1,«i, ».l.i 1

•

fWe oes', .17, 5.1 ?5

4*

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MIL-STD-T50A 12 Moy 959

front ocal , X B, B.U6 front vertex oca l , 3X9. B.11.7

Distortion, .6 .6 , .1.2.16 barrel, .6.6.1 pincushion, 3.6.6.1 radial, . 6 . 6X X2J6

tangential . 6 . 6X .1X16.7 Distorting en t with bject t nfinity, o r omput- in g elative llumination, .1X1L4-3 with inite bject istance, 6X2.11X4

Distortionless en s with bject t nfinity, o r om- puting elative llumination, 5X2114-1 with ünfte bject distance, .1.2.11.12

Effect, rism, .6.6.5, 51X17 Effective perture, 3X3, .12.9 Element 3X4 Environmental range, .7 JEquivalent ord ength, 81.4, 51X2

Errors f entration, . 6XS Extended ource ethod o r measuring -number

an d ranamittanee, 1X10J. o r easuring el - ative llumination, ,1211,1

Feather«, .8.18 Features, constructional, .8 Field, depth o f, 8X11

of view, J S tilt, 3X212

Film, hotographic , nd lates, .11.6 types nd laasea, 6X2121

Flange ut, 31X1

Flare, . 610 Flash ischarge amps, .1X4.1

f-nmnber, 3X61 marking of 4.1X3

Focal istance, back, .1.6, .12.4 flange, .1.7, 5.1X6 front , .18, .1.2.6 fnsjt vasts«, 8X8, «1X7

Focal length, calibrated, 31.6 , .1X3 äquivalent, 3.1.4, 6.121 marking f, 4.18

Peeal baft, 8X».l Focal ut , 21X21 Focus, epth of, 8X11

principal, 3,1.22 Focusing mount, en s mounted n , 10X6 Focusing cales, ccuracy f, .16 .3 Folds, 3.8.1.4 Format izes or air ameras, enera] ameras , .6

Front «parating perture, 8X7 Front oca l istance, .1 X .1X0 Front vertex back oca l istance, d.» , .1.27

Glare, veiling» 8.610, 6.1X19 Glass, hemical urability, .7.4.4

optical, .7.4

types, 8X9 Goniometer ethod o r easuring istortion,

61 X1 6 . 5 Graynees, SX28

Hartmann disk o r »«t»nl»r ring method o r nv»sui -

m g spherical berration, 5.1X18.1 Haze position, 8X9X2 High ontrast target, X1.7.1

Dlnmination, elative, .6.7, .1X11 Image uality, . 6 J L Index, cfi active , .7.41 Indirect computation method fo r measuring relative

flhnninanee, 6X211.4 Infinity, 5X1S Internal urfaces, .7 J Iris iaphragm, 8X4

marking o f, 4X4 specifying , 0X 6

J

K

L

Lamps, flash discharge, 5X1.4.1 Laps , 3X14 Lateral chromatic aberration, .6.4.2, 6.1.2.142

Lena, ron t of hotographic , .S.6 back o f hotographic, SX 6 Light , white, .1.1.4 Lines pe r millimeter, 6X1 . 7 Longitudinal hromatic aberration, 6.4.1, .1.2.14.1 L o w ontrast target, 6X17.3

Markings, .1 lens, .1 1 e*n,4.12

Mechanical nd tructural eature*. .4 Mechanica l xia, .1.8 Medium contrast target, .1.1.7.2 Member, 3.31

Methods, , quivalent ocal ength, v -*^«Taphir method, .12.2 .1

1A, quivalent focal lmgth, combination method, .1.2.21.1

2 quiv alent iaeeJ totgtfc, nodal «lldc nwthod .1.22 ?

3, 'ffectivr pwrtnrc. J crr.vwpt rfrthod, 5.1.29.1

4 9

8/14/2019 Mil Std 150a


8/14/2019 Mil Std 150a


MkUSTD-lSOA

12 .

18, 20 . 22, 25,

26 .

27.

31 ,

33.

34 ,

to r e t ho d . .1.2.12.1.1 fo r easuring esolving o w e r y arget

rang« method, .1.2.12.1.2

lor meamrin; rojected resolving power , 5.1.2.12.3fo r measuring ongitudinal h r o m a t i c ber-

ration, .1.2.14.1.1 for roeasuring lateral hromatic aberration,

5.1X14X1 lor measuring paraxial msamif ieat ion ,

5.1X16.1.1 fo r measuring istortion y target ange

m e t h o d , .1.2.16.1 for measuring istortion y ollimator bank m e t h o d , .1.2.16.1 fo r measuring istortion y ingle o l l ima- to r m e t h o d , .1.2.16.3 for measuring spherical aberration,

5.1X18.1 for measuring eiling lare y ac k pot

m e t h o d , .1X19.1 fo r measuring eiling lare y lack trip me t ho d , 5JX19.2

Plane of best definition, S.ai over the picture re a BADOPA), 3.1X1.1

Plane of he eceiver, .1.8.2 Point o ur ce e thod o r measuring ffective per-

ture, 5.1X9.2 Polish, o o r , 3XX11 Position, hale, .6.9.1.2

of greatest oncentrat ion , .6.9.11 Principal point of utoeo l l imat ion , .6 .6 .4

Prism ffect, . 6 . 6 .6 , 5.1X17 Projected photographic esoW in» power, 8.6X3 Projected "isual esolving ower , 3.6X4 Projection m e t h o d fo r measuring distortion,

5.1X16.«

Quality ontro l nd tatistic» data, 0.2.7

Radial distortion, 5.1X16 Radial esotring ower , .6.2 Reams, 3.8.1X1 Rear operating perture, .2.8 Receiver, lane of he. .1.3.2 Reference ist, 0.3.1 Reflect ion educing oatings. .7J2 Refraction, ouble, .7.4.3 Refractive ndex, .7.4.1. .8.1.7. .8.1.8 Relative llumination, .6.7. M_2.ll Rendition, ontrast, .6 .10 Resolving o w e r , .6.2

Photographic. X12.1. .6.2.1 projected , hotographic , .6.2-5, .1.2.; projected , est lat«, 1X12.3

projected , isual. .6.2.4. .1X12.4

taget, .1.1.7 target method for measuring

curvature of ield, .1X13.1

visual, 3.6X2, .1X12,2

Run-ins, 3X2.3.1

astigmatism an d

Sagittal esolving o w e r . .6.2 Scratches, 3.8X12 Seam, SX2JS Sections, eam, .6 .7.3 Shutter, en s mounted n , 0X3

Smears, 8.8X13 Spanner wrench openings, .4.7 Specific brilliance, 3.6.10

Speed, ens, 3X1 Spherical berration, .6 .9, .1X18

Spots, water, 3X2.13 Stain, .8X14 Statistical data nd quality ontro l , 0X7

Stones, .8.1.6 Stop, -, 4.1X1, 4.1XS

fractional, .1.4.3 opening, .1.4.2 T-, 3X6, 4.1X2, .1.4.4 T-, rea weighted verage, 8X4U

tolerance of marking, .1.4.4 3topped**pertarc m e t h o d for easuring spher ica i

aberration, 5.1X18.2 Strain, SX1.7 Stray ight. .6 .10 Striae, 3X1.8

Symmetry, o in t of, 5.1X16.1

Tangential distortion, S.6.6X 6.1X16.7 Tangential esolving o w e r , 6 .2 Target, igh ontrast, .1.1.7.1

lo w ontrast, .1.1.7.3 medium ontrast. .1.1.7.2 resolving o w e r . .1.1.7 range me t ho d , for measuring resolving power ,

5.1X12.1.2 fo r measuring istortion, .1X16 .1

Tetephoto. .3.8 rat io . .1.10

Test pparatus, .1.1 Test ondit ions , .1.1.6

Test e thods , .1.2 Tilt. i *W, 3.1X1.2

nanfr«, .1.3.1 focal. 3.1.3X1

Transmittance. ».68, .lX-0 T-nurober, X6

area eighted svirragf, .S.« I T-stop, .2 .6 . .1 .2.10

markings, .1 44

SI

8/14/2019 Mil Std 150a


MIL-STIM5QA 12 Moy fSf

v«iinr I»«». »-"Or "A» »* * r P** J*"1

VifMttiiit. .€.7.1 Wl* **"» 1-L*

Vimul making power, 3.6£2, £.Lt.lt* projected, 8.6.2.4, E.Lt.lX-4

62

8/14/2019 Mil Std 150a


FOL

FOiTAOE *«t> FCE» **«©

OFFICIAL »UWHtSS ««»tTv O R K : V A T E use f**>

ASD/ESYES Wright-Patterson FB, B JJ

S»OL

8/14/2019 Mil Std 150a


STANDARDIZATION OCUMENT IMPROVEMENT PROPOSAL O M B Approval No. 22-R255

INSTRUCTIONS: The purpose of fai» ern s o aolicit beaeficia] oauteat* which will bclo lie» »»«,- »en. of m.b.e product, t re..oo.ble oat nd miaü-u. da».,, r »U. otnemuVenwVSft. ZSL

DoD ontractor., overnment «etivitie«, r »aaufaeturar»/ vendor* «bo r» Drosoective .LNn,SL. 22"?- •"»vitad o »b«,« «-»ant. o b. „varn».,». Fo.d on ine. oTveT« ^ S-f2 prepann» act.r.ty. Comment, ubaitted on hi. or» do not oa.tih.te o. ap)y «thori«t Tw.ivt T

portion of he eferenced document«.) r o a»e»d ontractual iwv*~mmZ££Z£? 2j£ZS«

envelope addre.sed o preparing activity.

DOCUMENT DENTIFIER ND TITLE

NAME F ORGANIZATION AND DDRESS CONTRACT UMMER

MATERIAL PROCURED UNDER —

DDIRECT aOVCRNMENT CONTRACT SUBCONTRACT I. U ANY PART OF THE DOCUMENT CREATED PROILEMS O R REQUIRED NTERPRETATION N PROCUREMENT

A. «IVf PARAGRAPH NUMaCM AND «rORDIM«.

RCCOMMKMOATIOMS oR COKNICTIHa TH[ DEFICIENCIES

X . COMMENTS N ANY DOCUMENT REQUIREMENT CONSIDERED TOO RIGID

3. IS THE DOCUMENT RESTRICTIVE» Y EI NO (1 1 "Y»t", M pr.« mmrf)

«. R E M A R K S

tUAMiTTED «v <Prtnr«>«r nmlnM «itf «Mr*«» Oprlmat;

DD, ' r„1426 TELEPHONE WD.

DATE

»fUCI 1UIIION O 1 JAN •• WHICH MAV a. Ll»*ti <;/>. it o?-oi «- mo»

8/14/2019 Mil Std 150a


MII-STD-150A Change otice

8 une 96 1

M I L I T A R Y S T A N D A R D PHOTOGRAPHIC ENSES

TO AL L ACTIVITIES:

1 . he ollowing age f MIL-STD-150A as ee n revised an d supersedes the page listed.

NE W AGE ATE UPERSEDED PAGE AT E

29

June 1961

9

2 M ay 1959

2 . etain this notice nd nsert before the table f content*.

6IJ0S3—«1—(l|

8/14/2019 Mil Std 150a


MIUSTO - 150A 1 2 May 959

5JUL12^ Method Ik — rojected hotographic resolving power. This test is intended to be used primarily for enlarging lenses (type VI). A arget late f he equired size ontaining esolving ower argets

(light lines n ark ackground) nd f the required range, an d located as shown in Figure 8 , with on e se t of the lines in tangential an d th e other set in radial direction, shall be placed in the object plane film plane) f the lens to be tested. The targets shall be of high contrast T he target plate shall be even- ly lluminated y ight rom ondensing source. If required, the light shall be filtered to the olor required y lacing a filter between the light source an d he target plate. With the optical axis of the lens perpendicu-

lar to the target late, the lens shall be fo - cused t he esignated magnification nd aperture, nd n xposure ad e n he designated hotosensitive aterial. he photosensitive material hall e held iat in a plane erpendicular to the optical axis of the lens. T he correct exposure hall be that which gives the maximum resolution at position f igure . he est late s rocessed in tiie required manner. T he resolving power hall e ead y bserving he ry test plate nder suitable magnification. he

figures eferred o n measuring esolving power y his ethod re he ines er millimeter on he arget plate. t s ecommended that enlarging )ense3 be tested at a magnification of 1: 2 using medium contrast glossy hlorobromide aper rocessed % minutes n 72 eveloper, diluted :2 t 6 8° F.

5.1.2.12.4 Method 5 — rojected visvud resolving power.** This test is intended to be used rimarily or rojection enses type

Vil). A test object of the required size containing high contrast resolving power targets (dark lines on ight background) f the re - quired range an d placed as shown n Figure

e

a

c KP

CZ3D

< ? « A

^

oCD

<? E Ä E^

BbuxWnS UUwd ar atarabiüt* molrhi« &t*mr f avuw» ar ro jaa tan ar kom. t'd» mm ui

X MMti lUat. BM I4-1M7 (RwiMd K2).

FiCUBE . rojected Reiolvinfi ower Tett late

under est pon atte, white, rainleas screen. This screen shall be located at such a 8 hall e projected y means f he en s distance from the projector that unless other-

wise specified th e long dimension of the projected mage will e t east 0 nches * i order that the observer will have no difficulty in distinguishing the number of lines resolved . he resolving power f the en s t an y point n he ield s he argest umber f. lines per m illimeter in the teat object that an observer lose o he creen, ee s efinitely' resolved easily counted) n both radial an d tangential directions in the projected image. Care shall be taken to insure that the screen is erpendicular c he ptical xis f the

projection lens, an d hat the lens is focused so hat the image t the enter of he est plate has maximum ontrast. he projector used n his est ma y e a egular roduc- tion model r pecial est projector. he glass test object shall e a t an d e l < / concentric with an d ormal o th e optical xis of the projection lens. T he cone of light from th e rojection am p hrough ondensing system shall completely fill th e entrance pupil of the projection ens. he est object shiM be uniformly lluminated.

5.1.2.13 stigmatism nd urvature f field.

5.1.2.13.1 Method S — iesolving power target method. B y means of an y of the methods for measuring resolving power specified in methods 11 through 6 , esolving power

29

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MIUSTD-150A 12 May 959 shall e etermined or ifferent ositions

of the test plate n the image apace. The test

plate r lates are xposed n mall steps, at

different istances long he ptical xis f

the ens. he ength f ach te p epends

upon the corrections, focal ength, nd perture f he ens eing ested. ufficiently

large umber f teps hall e aken o n-

sure t least hree teps on ach id e of the

best ocus osition or oth adial nd an-

gential ines t ny ngular osition. Upon

reading the targets, the position of best focus

shall e etermined for adial nd angen-

tial lines separately) t which the resolution

is a maximum at each angular setting. These

focus ositions re lotted gainst ngular

settings, nd wo urves epresenting he two mage surfaces are btained. he curve representing curvature f ield s median

drawn etween he wo urves epresenting the mage urfaces. S ee . 6 .3 . ) he stigmatic ifference s btained y aking he difference n he ocal etting t pecific

angle or the wo mage urfaces.

5.1.2.13.2 M ethod 17 — Nodal ulide method.

This method may be se d n ieu f method

16 . In this method he en s to be tested hall

b e

et

p

n

ront

f

uitable ollimator equipped with arget ontaining; ertical and horizontal lines nd entered o that the optical axis is arallel o he ollimator axis

and coincident with he axis of the observing microscope. he ens hall e moved long

the microscope xis ntil he xis f otation f he odal lide ntersects he ear node. The microscope shall b e focused on the

axial mage nd he osition f he micro-

scope otedf T he ens hall hen e otated about he xis hrough he ear od e nd

perpendicular to the optical

xis

f the lens. At multiples f ngular ositions f /*

degrees u t o he dg e f he ield, he

microscope shall be separately focused on the

radicl and angential lines. T he focal chansre

from he xis osition hall e oted t the

angular ield ositions or he »dial nd

tangential ines. o btain urves uch s

specified n ethod 6 , he actor (l- cos 3)/cos s ubtracted rom he micro-

scope ettings, nd his ifference s multi-

plied y the os . f a lat ield ar s se d

at the microscope t s ot necessary to sub-

tract he actor (l-cos 5)/cos . he n

curves are obtained, the procedure for deter-

mining the urvature of field s he am e s

that n method 6 .

5.1.2.14 olor orrection. When he image

quality s ound atisfactory on he basis f

other pplicable ests, he olor orrection

ca n also be considered as satisfactory. Direct

measurements f olor orrections ay e

needed when some special color requirements

are o e met. hese measurements m ay e specified n erms f minimum esolving

power r imits n ndividual olor orrec-

tions.

5.1.2.14.1 ongitudinal hromatic berra-

tion.


method. Photographic resolving power meas-

urmenents hall e ad e s pecified n method 1 r 2 , tilising light of the colors

designated, repeating the

test

for

each color. T he ight se d may e upplied y mono-

chromator r t m ay e iltered white light,

as pecified. he ocus ositions t hich

the maximum esolving ower A W A R n-

less otherwise pecified) s btained shall e

determined or ach olor. The ongitudinal

color aberration for a articular color is the difference n ocal etting for this color an d

white ieht, r or this olor nd pecified

color. When he ocal etting or he irst

color is greater than the focal setting for the

reference

olor

r

white

ight, he

ongitudinal hromatic berration s aid o e

posi ve . enerally, he eference olor

shou d e owards he ed nd f he pec-

tral ange nder consideration.

5.1.2.14.1.2 Method 19 —Nodal alitU meUi,

od. he n specified, a odal slide ptical

30

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MIL-STD-150A CHANGE OT ICE 2 28 January 96 3

MILITARY TANDARD PHOTOGRAPH IC LENSES

8

4 5 7

10 17 22 24 26 27 84

T O A L L ACTIVrnES:

1. T h e fo l lowing pages of MIL-STD-150A hav e een evised nd upersede h e ages listed:

8

4 5 7

10 17 22 24 26 27 84

12 M ay 1969

12 M ay 1969 12 M ay 1969 12 M ay 1969 12 M ay 1969 12 M ay 1969 12 M ay 1969 12 M ay 1969 12 M ay 1969 12 M ay 1969 12 M ay 1969

2. h e o l lowing s umulative is t of earlier changes:

29 June 1961 29 12 M ay 1969

3. Retain th is not ice and insert before th e table of contents.

4. Holder of MIL-STD-150A will verify that page changes indicated above hav e been entered an d will destroy th e previous notice. Activities which stock these notices for issue are warned h at ach otice, ogether with its ppended evised ages, s n ffect a separate publication to be retained until th e military tandard s ompletely evised r canceled.

FSC67M

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3.1.2.2.1 W h e n ens s upplied n ells, without arrel 0/ Bhutter, he ocating urface of the lens mount is denned as the seat-

ing surface of the rear cell.

3.1.3 Meclumical axis. T h e me chan i ca l axis of a ens s that continuous traight line n space perpendicular to the plane of the flange o r ocating urface f he ens mount nd passing through he enter of ymmetry of th e lanpe r locating surface.

3.1.3.1 Flange tilt. The flange tilt of a lens is the an rle between the opt i cal axis and the mechanical axis.

3.1.3.2 Plane of the receiver. The plane of the receiver is that plane in the image space in which the receiver o r the film in a camera

is located.

3.1.3.2.1 ocal ilt. he ocal ilt s he angle between he lane f es t efinition and the plane of the receiver due to the m e- chan i ca l tructure etween he ens lange and the receiver. It is not a true characteris-

tic of the lens alone.

3.1.4 Equivalent focal length.* The equivalent ocal ength, or EFL, often eferred o m o r e simply as the focal ength, determines the scale of the inage produced by the 'ens. W h e n a riven objec ' s at an infinite dist;; c e, images roduced y distortionless enst f the same equivalent fopal length will be e ,ual in size, and images produced b.. enses of different quivalent ocal engths will var n size irectly s he espective quivalent focal engths. h e quivalent focal length s defined by the equaüon:

Y EFL

tan

ß f f L (1)

M1L-STD-150A 12 May 959

where /is the transverse distance from the principal focus to the center of the image n the mago-space ocal lane of n nfinitely distant object point which lies in a direction

making an anp.le ß with the optical axis. The equivaler ood length shal l be measured n a ccorda nce with 5.1.2.2.

3JL.5 alibrated ocal ength* h e alibrated focal length, r C F L , is defined as an adjusted value of the equivalent focal length of uns mounte d n ame ra r one , o c h o s e n s to distribute the distortion n h e manner bes^ suited to cond i t i ons under which the photograph s to be mployed. h e calibrated o es ength hall e etermined n

a ccorda nce with 5.1.2.3. T h e calibration c o n - ditions shaH be covered by the detailed speci-

f ication.

3.1.6 Back focal distance. The back focal distance, r BF, s efined s he distance measured rom the vertex of he ac k urface of the ens o he plane of best definition. The back focal distance shall be measured in c c o r d a n c e with 5.1.2.4.

3J..7 Flange focal distance. The f lange focal distance, r FD, s efined s he minimum

distance from the center of symmetry of the lens f lange n he plane of the flange to he plane of bi definition. In a perfect lens, this distance s easured long he mechanical axis which oincides with he xis f best definition. T h e fl:.nge focal distance hal l be measured in a c c o r d a n c e with 5.1.2.5.

3.1.8 Front focal distance.* The front focal distance, r FF, s efined s h e distance measured rom he principal ocus oca te d in h e front space to the vertex of the front

surface. he ront ocal istance hall e measured in a c c o r d a n c e with 5.1.2.6.

3.1.9 Front vertex back focal distance.* T h e

American andard ethod f Mlgnattn* nd aaaozinr. Focal cngthi nd ocal tataneaa f boto>i»l>hia UUM,

ZSS.4.21 — 1948.

> SM ootnote .

• Sa a aotnota .

Supenedea Pa»e of 2 M ay 959

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mum le a pening £ he urface which s actually med n orming n mage n ny part of th i ield. The mount aperture at each

surface sh ill b e at least as large as the clear aperture n rder hat ignetting will ot exceed he omputed alue. he lear perture s sually ircular nd pecified y ts diameter, t is ometimes eferred to as he free aperture.

0.2 .5 Re, aut aperture.5 The relative aper-

ture shall e defined as the ratio of the EFL

to the diameter of the effective aperture. The svmuol or elative perture hah e t followed y numerical alue. t is written as fraction, or example, f/2 signifies that the diameter of the effective aperture is one- half he ocai ength. or n bject t n infinite distance, the denominator of the relative perture md he econd member, N, f the aperture r.itio are identical, provided-the image is formed in air and the imagery obeys the sine ondition.

3.2.5.1 -numberfi The -number hall e defined as the denominator in the expression for he elative perture. Thus, f he ela- teaperture is f/2, he f-number is 2 .

3.2.6 T-stop and T-number.'' The T-stop is referred o s he perture f ens alibrated hotometrically nd ssigned - n umber, which s the f-number of a circular opening n ictitious ens aving 00 ercent trans:pittance, and which gives the same central mage illuminance s he actual ens at he pecified top pening. Hence, or lens with a ircular aperture, the

T-number =

f-number

Vt (3)

where t is the transmittam-e. For a lens with .m ffective *.:>erture v ny hape nd rea

* Oet- IU O t A O L W 4. tMlg« 4.

• M ** faotr.t'^; pair? .

American t:- l»rd. Aptrture L*»*« H21.90 - 19U.

MH.-STD-150A 12 May 1959

A, he orresponding formula is:

T-number =

VI)

2 * t The transmittance of the lens shall be defined as he atio f the transmitted ight flux o the ncident ight lux. he ymbol or he T-stop hall e T followed y a pace and numerical alue — or xample, . he numeral epresents he -number. F test rocedure, ee .1.2.10.)

3 .2 . 6 .1 Area eighted average T-nu/a .i -. The T-number s defined n . 2 . 6 s au parative measure f illuminance on he x; -

of a lens. Since the illuminance usually varie.- over the field, a need may exist for determining T-numbers for off axial im^ge points and computing an average T-number. In accordance with he asic hotometric elation- ships nvolved, he eneral definition f T- number is given as

--WwB/E, (5) Since, in accordance with this efinition,

« o -W E„

"E.

E, (6)

tlibrmtioc f o t i on lrtum

In these expressions, Tt s the T-number for an mage oint n one , T0 s he xial T-number, s he bject uminance, 0 s the lluminance n he xis, nd t s he average illuminance for the zone. Compatible units hould e sed or uantities B, „, and i. When he lluminance s veraged

over the field, weighting the average by the area of the circular zone in which the illuminance is determined, and this average is sub- stituted for Ei n equation 6), the resulting T-numLer s alled he rea weighted verage T-number, r AWAT. For circular zones which xtend eyond he oundaries f he

Superaedes Page f 2 M ay 959

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MII -STD-150A 12 May TW» picture ormat , nly h e rea ying within th e format shal l be sed in etermining th e weighting ratios. T h e equations fo r comput-

in g A W AT are:

A W A T = o

r A W A T - 0 T

(7)

o-, (8) in which A s h e rtal rea f h e picture format, A, s th e area of a particular one, and c r , is th e average relative i l luminance fo r that zone expressed in percent.

Z J 2 J J Front operating aperture. T h e front operating aperture is denned as th e l imiting aperture at th e front o f th e lens. It will usually be given as th e maximum diameter o f th e entrance o ne t h e ront ertex o r h e specified field of view at infinity focus.

3.2.8 Rear perating perture. h e ea r operating aperture is denned as th e l imiting aperture at th e rear o f th e lens. It will usually be given as th e maximum diameter o f th e

emergent o ne

t h e

ea r

ertex

o r h e specified field of view at infinity focus.

3.3 C O N S T R U C T I O N A L FEATURES. Pertinent features include details o f th e jn - struction o f th e tens. These m ay relate to th e phvsical onfiguration, r rrange neni f th e ndividual lements, o o m e pewhed optical characteristic o r to th e nomenclature o f th e various parts. Constructional features o f photographic lenses are listed with defini- t ions and explanatory data.

3.3.1 Optical ystem.» T h e ptical ystem includes all th e parts of a photographic lens and ccessory ptical arts w hi c h re e- signed to ontribute to th e ormat ion f an image on th e photographic emulsion o r o n a screen fo r viewing. juu.rim ff——» WOMB«*«»» * * • *

«llWi Lau BM M — 19**.

Z J & J Z Member.» ember f ho t o - graphic en s s group o f arts considered as n entity because of th e roximity o f its

parts r ecause t as istinct ut o t always entirely separate function.

3.3.3 Component.« A component of a photographic lens is a subdivision o f a member. It m ay consist o f tw o r more parts emented together r it h ea r nd pproximate . match ing surfaces.

3.3.4 lementfi n lement of hotographic lens s a single uncompounded ens, i.e., a part constructed o f a single piece. T h e " total number of elements is a significant constructional feature o f a lens.

3.3.5 ront f hotographic ens.« h e front f hotographic ens, n eneral, s th e en d carrying th e engraving, an d usually facing h e onger onjugate. n en s rawings, h e ront generally faces left o r up. A notable xception s ertain enses ntended to be used in photomicrography in wh i c h th * f ront o f th e lens faceB th e shorter conjugate.

3.3.8 Back of photographic lens.* T h e back

o f f hotographic lens, in general, is th e end carrying h e ounting hread r ther attaching eans nd sually ac ing h e shorter conjugate.

3 3.7 Name of design. Designs of lenses in wh m articular onfigurations of elements" ar e mployed re ften iven names. hese nam;s are usually trade names, an d th e name ordr arily applied to any particular configu- ration is usually th e trade name of th e oldest design of a particular type such as "Tessar."

In o m e ases, owever, h e esign am e m ay o t be trade name bu t m ay be based on o m e eature f h e en s onfiguration such as Symmetrical."

3.3.8 Telephoto. A telephoto lens is defined

«

•

• Aaaarfaaa Standard Tn—ili

(rauhte aaa HM» —IM

far arts * Rota-

8/14/2019 Mil Std 150a


as en s o r which h e elephoto atio s greater than one. See 3.1.10.)

3.3.9 Glass types. A constructional feature is h e yp e f ptical lass f which ac h element is made.

3.4 MECHANICAL A ND T R U C T U R A L FEATURES.

3*4.1 Cell. A cell is a mechanical structure holding an element, component , r member.

3.4.2 arrel. arrel s echanical structure in which th e lens is mounted.

3.4.3 one. o ne s " efined s h e mechanical structure to w hi c h a lens barrel or shutter, with lens, is attached in order to bring th e image in f o cus in th e film plane o f a specific aerial camera.

3.4.4 Lens iaphragm' A lens iaphragm is echanical evice o r educing h e effective aperture o f a lens. It m ay take th e form o f an iris o r a W a terh ouse stop. A n iris diaphragm onsist f eaves roviding n opening ontinuously ariable n ixe. W aterhouse stop is a removable aperture o f fixed size which fits in th e lens barrel. Water- h ouse stops are usually provided in a graded series o f apertures.

3.4.5 Iris diaphragm, control. Unless otherwise specified, wh en looking at th e f ront o f a en s r emote ontrol nob, ounter- c lockwise rotation o f th e diaphragm contro l shal l educe h e perture r to p h e en s down.

3.4.6 Parfocalized. Lenses mounted in barrels m ay be specified as parfocalized, i.e.) th e flange foca l distance m ay be specified to close tolerances h at would ecure n mage n satisfactory f o c u s w he n th e lenses are interchanged on a camera.

M1USTD-150A 12 May 959

3.4.7 Spanner wrench openings. W h e n required in order to facilitate removal o f cells, element«?, omponents, r members ro m

cell

r arrel, here hal l e w o penings 18 0 degrees apart fo r application o f a spanner rench. ach pening hall ither e circular n hape, r lo t with arallel sides.

3.5 FIELD OF VIE W . T h e field o f view o f a lens is a measure o f th e size o f th e image area o r conjugate object area which is satisfactorily eproduced. T h i s ield m ay e e- fined n erms f th e maximum size f th e negative r rojection material with which th e lens is to be used.« T h e angular measure

fo r field o f view is th e hal f angle, w hich , un- lesB therwise pecified, s h e ngle ubtended at th e first nodal point by th e optical axis nd traight line to n bject point which is imaged at th e extreme corner of the negative. Fo r rojected mage, h e alf angle s h e ngle subtended t th e econd noda l point by th e optical axis and a line to th e image point conjugate with th e extreme corner o f th e projection material. h e h a l f angle s ometimes eferred o h e id e f th e mage rea and'in uch ases t hal l

always be so specified. T h e field o f view m ay also e esignated s h e otal ield ngle which is twice th e ha l f angle. Coverage is a less precise term fo r field o f view.

& * OPTICAL CHARACTERISTICS. Opti- cal characteristics include all properties o f a lens ffecting it s optical erformances such as mage uality, istortion, ransmittance, image olor, nd ondenser haracteristics. W h e n pecifying ptical haracteristics r individual berrations, h e efinitions nd nomenclature set forth herein shal l be used.

3.6.1 mage uality. mage uality m - »Formal SÜaa o r A ir Cutrw, AB C AH 8R> t/1. Fife.

M . ba artMpaat» mtrm* h at ir amera orma t taa* ball ba: K r t*t acbaa. % by 4% Bobaa. by • teebaa, • br « Inobaa, 8 r S nebaa. orma t la w or roan* anaraa. AB C IR T D M/i, 5 ar . . round amara orma t iao> ttt,^.«».- baU bai y V oebaa M y I nmiiatari). Ztf y * aeba», .S y .U aahae.

Supersede« Page 7 o f 2 M ay 959

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M H-S TD -1 50A f2 May 909

braces al l th e roperties of a lens ffecting th e uality of th e mage uc h s esolving power, aberrations, image defects, an d veil- in g glare. Aberrations are optical defects in -

herent in th e lens design. Because of manufacturing ariations, t ften appens h at th e easured berrations iffer ro m h e computed berrations. mage efects re optical defects not inherent in th e lens design and esulting ntirely ro m manufacturing an d mounting ariations. h is tandard s primarily oncerned with ptical erformance. Optical performance can be measured in erms f esolving ower , r pecific optical characteristics.

3.6 J Z Resolving power. T h e resolving power of a lens is a measure o f its ability to image closely spaced objects so that they are recog- nizable as individual bjects. T h e resolving power shall be expressed in lines per millimeter, usually in th e s hor t conjugate plane. Resolving power is measured by photograph- ing o r observing suitable test charts at specified H t g f t l * * » istances ro m h e enter of th e ield. h e est harts hal l onsist of groups of parallel straight lines and^spaces of equal width; h e esolving power s th e

reciprocal f h e enter-to-center istance of tiie lines that are just distinguishable in th e ecorded mage. y ost istinguishable" s meant that th e observer s ble to c ou nt th e correc t number of lines in th e recorded image» over th e entire length of th e fines an d in th e correc t orientation, subject to th e provision that no c oarser pattern shall be tnuresolvsxL T h e appearance of resolution in a finer pattern after failure to resolve a coarser pattern is an indication of th e presence o f spurious resolution. Spurious resolu- t ion is a phenomenon wherein fine lines are resolved, yet coarse lines are not . For non- axial points, t is necessary to consider th e orientation of h e ines. o r xample, h e resolving power for radial lines, r "radial resolving power": (sometimes called "sagittal resolving power**), at a given aint n th e

image j lane is th e resolving power fo r closely spaced lines that are parallel and adjacent to th e radius drawn from th e center o f th e field to th e given point Resolving power fo r

tangential ines, r tangential esolving power," s h e esolving ower o r losely spaced parallel lines that are tangent an d ad - jacent to circle drawn through th e give point w hos e enter lies at th e center o f th e field. Resolving ower m ay e pecified s mfn-itniim cceptable esolving ower, e- gardless f whether radial r tangential t specified angles from th e optical axis o f th e lens, o r it m ay be specified at both m inimum acceptable adial nd minimum cceptable tangential resolving power at specified angu- la r distances from th e optical axis. T h e average esolving ower weighted n erms f th e area o f th e negative, the area weighted average esolution A W A R ) , rovides single alue by which th e esolving ower fo r h e ntire ield m ay e pecified. S ee 3.121.1 and 3.6.2.5.)

3.6.2.1 hotographic evolving ower. Photographic esolving ower s sed n specifying nd measuring erformance f type I, II , H I, IV , V, IX , XII, an d Xm lenses and is th e greatest number of lines per milli-

meter recorded photographically as separate lines. A target pattern is considered resolved when t meets h e onditions escribed n 3.6.2. Photographic resolving pow* r depends markedly n h e hotographic onditions employed, nd n h e resence f ackground lare ro m h e lluminated arget. W h e n pecifying hotographic esolving power, t s ecessary lso o pecify h e co lor of l ight to be used, th e type of photo - sensitive material nd rocessing, h e en s speed at which th e test is made, th e contrast

o f th e target, an d th e magnification o r f o c u s at w hi c h th e lens is tested. See 5.L2 .12 .L)

3.6.2 .; Visual resolving power. Visual e- solving ow e r s sed n pecifying nd measuring of type X enses, nd s efined as h e reatest umber of ines er milli-

•

•

8

8/14/2019 Mil Std 150a


meter n h e mage f a ea t target pattern that re ust arely istinguishable s separate lines under adequate magnification.

W h e n specifying visual resolving power it is necessary also to specify th e target contrast. (See 5.1.2.12J2.)

3.6.2.3 rojected hotographic esolving power. rojected hotographic esolving power is sed n pecifying nd measuring th e erformance f vpe V I enses nd s defined as h e reatest number f lines er millimeter, in th e object plane, that are barely istinguishable s eparate ines h en observing nder agnification hoto - graphicall-- ecorded, rojected mage f suitable t< st arget. See .1.2.12.8;) h en specifying rojected photographic resolving power t s ecessary lso o pecify en s speed, focus, magnification, type o f illumination, ontrast f target, ype hotosensitive material nd ts processing.

3.6.2.4 Projected isual esolving ower. Projected visual resolving power is sed n specifying nd measuring h e erformance o f ype II enses nd s efined s h e greatest umber f ines er millimeter n

th e object plane t ha t are distinguishable as separate lines in th e projected mage. W h e n specifying projected visual resolving power, it is usually understood to imply a high co n- trast arget dark ines n ight ackground). See 5.1.2.12.4.)

3.6.2.5 Area weighted, average resolution. A ingle verage alue or h e esolution over th e picture format m ay be determined fo r ny iven oc a l lane s h e rea weighted verage resolution, r A W A R . o determine th e A W A R , th e picture format is

divided into concentric annular zones w hos e boundaries re determined ro m th e ngles which re midway etween uccessive est angles. Fo r ones which xtend eyond h e boundaries f h e icture orviat, nly h e area ying within h e o r ma t hall e sed in determining th e weighting ratio. T h e reso-

MIL-ST&-150A 12 May 9S9

lution btained t ny iven est ngle s multiplied y h e atio f h e rta f h e zone fo r that angle to h e total rea f h e

picture ormat. h e A W A R s h e um f these roducts. o btain ingle value f th e esolution o r ac h test ngle, h e eo - metric mean f h e angential nd adial resolutions shall be used. However, th e co m - putations m ay be simplified by th e use o f an arithmetic ea n henever h e angential an d adial esolutions iffer by ess h an factor of 2 to 1. W h e n more than one measurement is made at any given test angle, an arithmetic mean shall be determined fo r th e tangential nd nother o r th e adial esolutions. h e

re a weighted verage esolu-

tion is defined as:

^

A , A W A R ^ —- JR ,

A N 9) where Ai is th e area of a particular zone, t

is th e average radial resolving power in tnis zone o r radial resolving power at th e midpoint of th e zone) , T t is th e average tangential resolving power in th e zone o r th e tangential esolving ower t h e idpoint of th e zone), nd A is th e total area o f he picture ormat , nd s h e ummation sign, summating th e values

A ,

over al l zones in th e picture area.

3.6.3 Astigmatism an d curvature of field. In general, a lens possesses tw o mage surfaces : o ne in w hi c h lines radial to th e optical axis are best defined an d th e other in w hi c h lines angent to ircles oncentric with h e axis re es t efined. oncoincidence f

these wo mage urfaces s alled stigmatism, an d th e separation of th e tw o image surfaces, easured arallel o h e ptical axis, s alled h e stigmatic ifference. median urface ying etween h e w o s called th e surface o f least confusion and th e definition n h is mage urface s least

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MIL-STD-150A 12 May 999 affected by orientation of the object None of the surfaces is a true plane. The departure of the urface of east onfusion rom rue plane s alled urvature of field. Resolving power igures, pecified n ccordance 'with ,8.6.2, will usually be considered as referring to a flat image and object plane. W h e n curvature of field is specif ied, the magnification at which t s o e measured hall e tated. (Sae 42.18.) igure s lotted s n Example of the astigmatic difference.

AH6ULA* NSTANCE FMH AXIS PlOUU AetigvuMe Diferenee

34.4 C o l o r correction. C o l o r correction s defined as the reduction of longitudinal nd lateral hromatic berrations. t ay e specified n erms at he kind f ight nd color ensitivity of he photographic mate» rial to be used with the lens, e.g., the lens is

color corrected for use with white light and panchromatic ilm f ASA peed 00. he color correction may be specified in terms of the Fraunhofer ines n he olar pectrum

that are to e se d n he ens alculat ions , e.g., C nd F orrection. The magnification at which the co lor correction is ^ accompl i she d shall be designated. See 5.1.2.14.)

3.6.4.1 Longitudinal chromatic aberration.

Longitudinal chromatic aberration is defined as a variation in back focal distance for light

of ifferent o lors r ave engths. t s specified n erms of his ocal hange or light f pecified o lors . See .1.2.14.1.) Figure s lotted as n xample of longitudinal chromatic aberration.

S.C4L2 Lateral chromatic aberration. Late-

-M « ♦ xa ♦ .t o FOC AL CHAH6E (nn)

FiOUKK 2. onnitudmal Chromatic A'temtiov

ral hromatic berration s variation r. image cale of ens or ight of different colors r are engths. h en equired, limits on ateral hromatic aberration will be pecified s he adial displacement n

millimeters of he mage a he irst o l o r from he mage f he ame oint n he second o lor . See 5.1.2.14.2.) igure s plotted as n xample of ateral hromatic aberration.

4L

,_ <*> X M

Jo *0 L So «£ > 7 < J o

WA V E ENGTH Or L I S HT (rtO)

FK;UKB . ateral Chromatie Aberration

3.6.5 Magnification.

3.6.5.1 Paraxial magnification. The paraxial agnification, ften eferred o o re simply as magnification, determines the scale of he mage when he object s at a inite distance from the lens. The paraxial magni- fies o n , r PM , s efined by he ollowing

equation: /

PM = l imit 10) y

y ¥- where/is th e radial distance from th e opti- c al axis to th e image point in the image plane

•

Sa p MMd « Pas« 10 o f 12 M ay M S 10

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3.8.1 Material defects.

3.8.1.1 B bles. Bubbles ar e air o r gaseous

inclusions entrapped within th e glass.

3.8.1.1.1 eeds. eeds ar e very small bubbles

3.8J..1.2 Air bette. A ir bells are irregularly shaped bubbles

3.8.1.2 Cracks. Cracks are shallow separa- t ions or ireaks in th e glass.

3.8.1.3 eathers. Feathers re owdered surfaces folded into th e glass in th e pressing process.

3.8.1.4 Fold, r aps. Folds, r aps, re areas n hich h e lass as een olded upon its« If bu t no t fused.

3.8.1.5 ükiness. Milkiness s aused y cloudy o r milky areas within th e glass.

3.8.1.6 tones. tones re ragments f undissolved material in th e glass.

3.8.1.7 Strain. Strain is tension within th e glass caused by inadequate annealing o r im - proper mounting. t is n re a of index f refraction differing from th e nominal .

3.8.1.S triae. Striae re streaks or veins in th e glass with th e index o f refraction differing from that of th e body o f th e glass.

3.8.1.8.1 Reams. Reams re fine ands f striae.

3.8.1.8.2 Cords. Cords are streaks o f very heavy striae.

3.8.2 Manufacturing defects.

3.8.2.1 Blisters. Blisters re ubbles n cement layer.

MIL-STD-150A 12 ay 959

3.8J2.2 urns. urns re eddish tains generally round n h e entral reas f elements h ey re sually aused y h e

drying-up o r glazing o f a polisher.

3.8.2.3 Cement tarts. ement tarts re spots where h e omponents f emented lens ave tarted o eparate. h ey c an e small rregular pots etween h e lements o r run-ins at th e edge, insufficient cement, or cement at th e edge dissolved by a solvent.

3.8.2.3.1 Run-ins. Run-ins are cement sepa- rations t h e dge - o f emented omponent.

3.8.2.4 Chips. Chips ar e areas from which glass as een roken w ay ro m th e urface, edge, o r bevel o f an optical element.

3.8.2.5 racks. Cracks re reaks n h e glass.

3.8.2.6 Digs. Digs re reaks f th e o l- ished surface o f a round, val, square, etc., shape ncluding its, oles, nd urface broken bubbles.

3.8.2.6.1 Dirt holes. ir t oles re igs filled with rouge.

3.8.2.7 Dirt. Dirt consists of dust, lint, r other oreign matter on h e urface r n- trapped in a cement layer.

3.8.2.8 Grayness. Grayness s represented by finely ground areas indicating incomplete o r improper polishing.

3.8.2.9 Mold marks. Mold marks ar e marks on th e surface produced by molding.

3.8.2.10 Orange peel. Orange peel is poorly polished urface , ock-marked it h its, having m u ch h e am e urface ppearance as th e skin of an orange.

3^J2.ll oor polish. P oor polish pertains

Supersedes Pafe 7 of 2 M ay 959 17

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MIL-STD-150A 12 May 9S 9 to olished urfaces ontaining minute pits o f a gray o r red color. T he y ar e gray grind- in g pits n th e surface o f th e lass, r ed grinding pints n which ouge as een o

deeply mbedded that t h as to e emoved by further polishing.

3.8X12 Scratches. cratches re urrows o r grooves in th e surface o f th e glass caused by h e emoval of lass, sually made y coarse grit, fragments o f glass, harp tools, etc., ubbed over th e surface.

3.8.2.13 mears, cum, water pots, tc. Smears, scum, water pots, etc., are residue o f vaporated r nevaporated oisture. T he y re sually emovable y normal"

cleaning.

3^X14 tain, tain s discoloration f th e lass urface, sually rown, lue, r green, caused by th e deposit of foreign matter, r changes roduced n h e urface f th e lass y hemical ction f o m e ubstance with th e glass.

4. ENERAL EQUIREMENTS

4.1 MARKINGS.

4.1.1 Lens markings. Lens markings, such as maximum aperture, f oca l ength, ield of view, nd erial number shall be placed n th e front of th e lens cell o r on th e barrel if space imitations so require. h e lens name and serial umber shall be ssigned y th e manufacturer.

4.1.2 CeU marking. Lenses supplied in cells o r onstructed ith emovable ells shall have ll ells ermanently marked with t

least th e ast three digits of th e lens serial number.

4.1.3 aximum perture. ll ypes f lenses, xcept ypes nd I, hal l e marked with their maximum aperture stated eith er as th e relative aperture, aperture ratio o r T-etop.

4.1X1 T h e symbol fo r relative aperture of a lens shal l be f/ fol lowed by th e numerical value, for. example f/2.O.**

4X3.2 T h e symbol for th e T-stop of a lens shal l be T fol lowed by a space and then th e numerical value, fo r example T 2X

4.1X3 f-nwmber.i* T h e effective diameter

o f th e maximum perture f h e en s hail

be t east 5 ercent of h e uotient b- tained y ividing h e marked focal ength by th e f-number corresponding to th e maxi- m um marked aperture.

4.1.4 Iris diaphragm control marking.

4.1.4.1 Full stop.** T h e standard series o f diaphragm markings, o r stop openings, shall be 0.7, 1.0, 1.4, 2.0, 2.8, 4.0, 5.6, 8, 11 , 16 , 22, 32 , 45 , 6 4, 90, an d 128.

4.1X2 Maximum aperture value. T h e f- number corresponding to th e maximum aperture, -number, r perture atio alue marked need no t be selected from *V above series ut hall e ol lowed y h e bove series of stop penings eginning with h e next largest number whenever practical an d progressing as far as required in th e individ- ua l pplication; .g., o r n /1.9 en s h e diaphragm might e marked /1.9, 2.8, 4.0, 5.6,8, etc, if it w as believed that to mark it f/1.9, .0 , .8 , .0 , .6 , tc., would onfuse

th e marking at th e f/1.9 en d of th e scale.

4X4.3 Fractional stop values. In addition to h e umbered alues, ach to p ma;' e divided nto hree ubdivisions y o ts r marks no t umbered), h e o ts eing t "thirds of a stop," e.g., 0 . 7 , 0.8, 0.9,1.0, 1.12,

•

18

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solving power target, used n ll tests hall be s ollows: he target hall onsist f a series f atterns ecreasing n iz e as he

V 2 , f2 , J / 2 , with a range sufficient to cover the requirements of the lens-film combination under test. T he standard target element shall consist f wo atterns tw o ets f lines)

' at right angles to each ther. Each attern shall onsist f hree ines eparated y spaces of equal width. Each line shall be five times as long as it is wide. S ee Figure 7.) For types I an d II lenses, targets with light lines n dark ackground re referred; for types V, V I, VII, XII, XII enses, argets with dark lines n ight ackground are preferred. T he target contrast the difference in photographic density between the lines nd paces) hall e ither igh, medium, r low contrast, as specified.

> -

-<2* Kfe *r FIGURE . tandard Resolving ower Tett Target

Element. he attern* f ines re arallel ute*

£.5 millimeter* ong nd .5 millimeter* wide

with space .5 x millimeter* wide between the paral-

lel ince, where qual* he number* f ine* er

millimeter.

5.1.1.7.1 High contrast target. A high contrast target is on e in which the density difference between the light an d dark areas is greater than 2.00.

5.1.1.7.2 M edium contrast target. A medi- u m contrast target is ne n which he density ifference etween he ight nd ark areas s equal to .8 0 : .05.

5.1.1.7.3 ow ontrast arget. A ow on - trast target is on e in which the density dif-

MSUSTD- ISOA 12 May 959

ference between the light nd dark areas s equal to 0.20 ± 0.05.

5JL.2 Test methods.

5.1.2.1 Plane of best definition. T he plane of est efinition s sually etermined y making a series of evaluations at a sufficient n u m b e r f ocal ettings. he istance e- tween focal ettings in hundredths of millimeters shall be at least

f-number of lens

no. of lines/mm. expected

T he etailed pecification hall tate he

method used in determining the plane of best definition.

5J..2 .2 Equivalent foca l length.

5.1.2.2.1 Method 1 — Photographic method.

1* T he EFL shall be measured by placing

a photographic plate in the focal plane of the image space. Unless otherwise specified, the. focal lane s efined s he lace f est photographic imagery for an infinity distant axial point; the focal plane may also be specified s the plane of best definition. A collimator and reticle m ay be conveniently used to provide an infinitely distant object point. Exposures are made with the beam of light from the collimator directed along the optical xis f he ens nd eries f ngles ßu ßt , etc n the resultant negative, measurements hall e ad e f he istances Vu Yu tc., rom he xial mages o he images orresponding o he ngles u - . ,

i /:etc., nd he uotient -

tan ßt tan ß.

etc., formed. he limiting value of this quotient as ß approaches zero is the EFL. In a photographic bjective free from distortion, the quotient is invariant with respect to the

M American tandard Mbedi o r arignattaiff nd int ocal anaüw nd o ca l Dtoan ot i of hotograpUa ZSS.4.21-1MS.

2 1

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MIL-STEM 50A )2 M ay 959

value of ß. Fo r many photographic purposes th e distortion ia negligible fo r points distant from th e center o f th e useful ield no t mor e

tiian ne-fifth o f its radius, an d consequent- ly , t will very often be possible to obtain satisfactorily ccurate alue f h e FL by a »ingle determination f ß nd •/ fo r a point lying near th e axis.

5.1.2.2.1.1 ethod A ombination ethod. T h e EFL lso m ay e etermined

by dding th e photographic BF o h e istance from th e ea r vertex to th e emergent noda l oint. h e atter istance ay e determined by Method 2.

5.1.2.2.2 Method t — Nodal sUde method. T h e lens to be tested hal l be mounted n a noda l lide to rotate bout th e vertical xis through its second nodal point. T h e distance .from th is nodal point to th e position f best axial oc u s or n nfinitely istant bject point shal l be measured. T h i s s also known as th e second principal focus. A n important factor r ncertainty n sing this method is th e difference between th e position of best focus as judged visually on th e optical bench and th e best focus as determined photograph-

ically by method 1.) W h e n using this method, h e riterion or etermining h e es t axial f o cus should be specified. T h e criterion used s dependent on th e type o f test object or target used an d m ay be specified in terms of either th e haze position o r th e position of greatest oncentration se e .6.9.1.1 nd 9.6.9.1.2) r n erms of h e o lor n nd around th e image.

5.1J2.3 Calibrated ocal ength. W h e n e- termining h e alibrated oeal ength, h e

plane f es t verage efinition hal l e chosen s h e o c a l lane. o ompute th e calibrated foca l length, le t /„ /, etc, repre- sent h e istances n h e o c a l lane ro m th e xial oint o h e mages of nfinitely distant object points lying in th e direct ions making ngleB ßx, ßt, etc, with h e ptical axis of th e bjective. f is h e equivalent

focal length in th e absence of distortion, then

/, = f an 3 , 13) /,= f an ßt

an d /„ = f an ßu

•

In h e presence of distortion

and

< y \ = f an 3, y\ /,= f an S , - A /,

/.= f an ßa /.

(14)

(15)

(16)

T h e added terms are th e values of th e linear distortion fo r values / 3 „ ßt, etc, respectively. T h e values of /and ß are measured directly. It is evident that th e individual values of th e distortion efined y h e bove roup f

equations an e hanged y hanging h e value of f. If f is th e equivalent foca l length, in many instances values f th e distortion in th e eighborhood f h e xial mage oint will be small, nd near th e edge o f th e field th e alues will e arge nd redominantly negative o r positive. Infinitely distant targets m ay e rovided y roup of oll imators o r y ne ol l imator which an e ucces- sively laced n h e equired ngular osi- t ions. Exposures hal l e made nd h e /corresponding to each angular distance from

th e optical

axis shal l

be determined.

5.1X4 Back foeal distance. T o determine th e BF, th e foca l lane in h e mage pace shall e etermined y isual r ho t o - graphic method . T h e measured distance from th is o c a l lane o h e ertex f h e ack surface of th e lens shall be th e required BF.

5.1 JL 5 Flange ocal istance. T o etermine h e FD, h e oea l plane n th e mage space hall e etermined y isual r photographic ethod. he easurement shall be made from the plane of th e loc at ing surface o r th e flange to th e foca l plane.

5X2.6 Front ocal istance. T o etermine h e FF, h e o c a l lane n h e bject space hal l e etermined y isual r

» S» oo t no t e 4. a*» U.

•

S«pi«ii» ar« a «f IS M a y IM t 22

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photographic met .od. The measured distance from his ocal lane o he ertex f he front urface f he ens hall e equired

FF.

5.1.2.7 Front vertex a ck ocal istance. T o etermine he V D , he ocal lane n the image shall be determined by a visual or photographic ethod. he easured istance rom he ertex f the ront urface of he ens o he ocal lane hall e he required FVD.

5.1.2.8 Aperture ratio. For the special case in hich he bject s t nfinite distance (magnification ), N , he irst member of he atio quation 2) n . 2 . 2 , may e determined s he uotient btained when th e EFL s ivided y he diameter of he effective aperture.

5.1.2.8.1 For the general case in which the magnification m ay av e ny alue, in - hole should be mounted at the axial point of the esired mage lane, nd he ngle f the cone of light emerging through the pinhole from the lens should be determined y measuring he diameter f ight ection

of the cone at a suitable distance beyond the pinhole. T he angle a can be calculated from the measurements nd ubstituted n quation 2). f s the ndex f refraction f the me-lium n which he ngle s me - ured r or air, se d n the great Ma- jority f ases), he econd member f he

1 aperture ratio is

2 n sin a When measuring he perture atio y he method f this paragraph, the angular sub- tense f he bject oint t he irst odal

point of th e hotographic objective must be small s ompared with he alue f he angle etween he ptical xis f he objective an d the extreme ray proceeding to the image point.

5.1.2.9 Effective aperture.

MIUSTD-150A 12 May 959

5.1.2.9.1 ethod Microscope method. A raveling ompound microscope s requirer'. with eans or ranslating he

microscope in irection t right angles to its optical axis through a measured istance not ess than the diameter of the maximum effective aperture to be measured. T he microscope must be f ow ower 10 X o 0X ) provided with reticle an d with working distance su fficiently long to permit the microscope to be focused on he limiting opening of he hotographic bjective hrough he front member. T he photographic objective, o f which he ffective perture s o e measured, shall be mounted in a convenient position o ermit he raveling microscope o be directed parallel to the optical axis of the objective nd ocused po n he edge f the opening having the smallest apparent diameter. T he hotographic bjective s ot to e isassembled.) his dg e hall e viewed through the lens elements which are normally raversed y mage-forming ight before assing hrough he imiting pening. microscope aving on g working distance s equired o void mechanical interference when ooking through he ens elements. A microscope hall hen e rav-

ersed and measurements made to determine the apparent diameter of this opening which shall be the effective aperture. n place of a traveling microscope, a suitable contour projector may be employed to measure the effective aperture. f the lens has a non-circular aperture, he measured iameter must e suitably corrected.

5.1.2.9.2 M ethod 4 — Point ource method.i7 W h en t s ot racticable o se microscope of sufficient working distance to permit he imiting opening o e

bserved through the lens elements, a source of light, as small s racticable nd mitting a cone sufficiently arge o ill he ens, may e

" American tandard Mathod* f Daatanatint' nd Maaauina, Apartum nd alatad uantitlaa artalnins o ho t o sra nU a La nna . ZI8.4.20-1M8.

« American tandard Apartor* alibration of Mot ion Pteora LaflM*. H2S.M —19U.

23

8/14/2019 Mil Std 150a


Mlt-Sm-T50A 12 M ay m»

placed t h e econd rincipal ocus nd directed oward h e bjective; h e iameter of iie mergent ea m hould e measured as near th e f ront of th e objective as is prac-

ticable. T h i s method s subject to a system- atic error, th e value of th e finite size of th e source.

5.1.240 T-number an d transmittance. T h e equipment specified n methods nd fo r determining T-stops an d transmittance o f a lens epresents orkable pparatus. o w- ever, odifications re ermitted rovided that h e asic requirements of h e method an d h e pecified ccuracy n et . See 3.2.6 and 4X4.4.)

<

5X2.10.1 Method — Extended ource method. T h i s method of lens calibration is based n filling- th e lens with light from an expended uniform source o f adequate size an d placing in th e plane of best definition of th e leas a metal plate with a hole , th e diameter of which shal l no t exceed 3 millimeters o r 1.5 millimeters fo r &-millimeter film), at it s center. h e ight lu x assing hrough h e ho le shall be measured by a photocel l

arrangement. h is lu x hall h en e o m - pared with th e flux passing through a ho le of th e same imensions ro m n pen circular aperture of uc h iz e and at uch istance ro m h e late h at t ubtends h e desired angle a so that sin o r = % T , where T s h e -number o e easured. T h e greatest ar e s ecessary o nsure h at th e extended source is niform. n practice, th e hotocel l reading o r ach ho le - number s irst etermined o r eries f open apertures t a fixed distance from th e plate. h e en s s h en ubstituted o r h e open perture ith h e -millimeter o le accurately n ts oc a l lane nd h e ris of h e en s losed o w n ntil h e hoto - cell meter eading roduced y h e en s s equal o ach f h e uccessive pen o le

readings. h e full -stop ositions re then mark :d n h e iaphragm in g of th e ens. T h e ntermediate hirds f tops ay e found with ufficient ccuracy y nserting a neutral density filter o f 0.1 nd 0.2 behind each pen perture n urn nd oting h e corresponding hotoce l l eadings r y i- viding h e ravel f th e iaphragm ontrol into three qual arts. h e xtended ource should e niformly right ver ts seful area o within t3 ercent. T h i s ould e tested with uitable elephotometer, r a small o le n n paque creen ould e moved round n ront of h e ource nd any consequent variations in photocel l read- in g oted.) h e ource m ay e heet f

ground glass covering a ho le in a whitelined bo x containing several lamps mounted around th e hole an d shielded so that no direct l ight from h e amps alls n h e round lass itself. h e photocel l eceiver m ay e f th e phototube type with imple -c mplifier. Care must e aken o nsure h at hoto- tube ensitivity o es o t hange etween marking readings on th e open perture an d o n th e lens itself. T o guard against this , some turret rrangement s esirable, it h h e lens on o ne side and th e open aperture on th e

other , so hat th e tw o m ay be interchanged an d ompared uickly with ac h ther y turning th e turret. Transmittance of a lens shall e measured at th e maximum relative aperture in a direction parallel to th e optical axis of th e ens. ransmittance s qual o C /R where C is th e calibrated photocel l read- in g with th e lens in place, an d R is a similar reading when a clear circular aperture is in place, ubtending n ngle a at th e o le n th e front of h e hotocel l o h at in i ^ N , where N is th e second term in th e aperture atio f h e en s o e ested. See 32.2.) T h e value of N must be th e true value, which m ay differ from that indicated o n th e barrel

5.1.2.10.2 Method — ColUmator method. In h is ethod, ight ro m mall

•

•

* Sw oataat* U, » am rr*irrAit 7, U.

SnpwMdM P«f« 3 4 o f I S Mar fM 24

8/14/2019 Mil Std 150a


source (a -mi.iimeter o le overed it h opal glass and strongly illuminated from behind) hall e ollimated y simple ens,

o r an achromat if preferred, o f a f o ca l length at least three t imes th e EFL o f th e lens be- in g tested an d o f sufficient aperture to fill th e lens eing alibrated. h is ives ollimated ea m which will e ocused y h e test lens to form a small circle of l ight in its foca l lane. h is circle o f l ight will be less than h e rescribed imit f millimeters diameter. Uniformity of th e collimated beam can e hecked y moving mall o le n an paque screen across th e beam, and not- in g any variations in th e photocel l reading.

Fo r th e omparison nit, n pen aperture shall be used, o f diameter equal to th e focal, length of th e lens divided by th e desired T - number. T h i s aperture shall first be mounted in r o n t f n ntegrating phere f dequate size with th e usual photocel l detector an d h e ight ro m h e oll imator llowed to nter h e perture. h e perture late shall h en e eplaced y th e ens, h e ris diaphragm losed o wn o iv e h e am e photocel l eading, an d th e -number n- graved n h e ris ing. h e ntermediate thirds of stops.can be found by using 0.1 o r

0.2 ensity filters, o r by dividing th e travel o f h e iaphragm ontrol nto hree qual parts. T o guard against "drift" o r line-volt- age ariations w hich might ccur etween readings o f th e comparison aperture and th e lens, t s onvenient o eave U te nown standard perture n lace n ront f th e sphere, an d to insert th e lens into th e beam

in uch osition h at th e mall mage f th e source falls whol ly within th e standard aperture. T h e meter reading should then re- main th e same with th e lens in or out o f th e

beam. econd late with -millimeter aperture should be placed over th e compari- so n perture hile h e en s s n lace to stop any stray l ight which m ay be reflected from h e nterior f h e ens. t hould e noted articularly h at f h is ethod s used, h e o c a l ength f h e en s must e

»* * • ' fc-STD-HMA*' 12 M ay 95 9

measured eparately nd uitable et of open apertures constructed o r use with t. However, by suitable devices, o ne single se t of fixed apertures m ay be used fo r all lenses. Transmittance o f a lens shall be measured at th e maximum elative perture n irection parallel to th e optical axis o f th e lens. Transmittance s equal o C /R where s th e alibrated hotocel l eading ith h e lens n lace, nd R s imilar eading when clear iaphragm equal to th e en s effective aperture) s in place.

5J..2.11 Relative fflumination.

5.L2J.1.1 ethod — Extended ource method. T h i s method o f measuring relative illumination makes use o f th e same appara- tu s nd echniques pecified n ethod . W it h th e lens to be measured et up in h e apparatus, h e hotoce l l hall e isplaced laterally to th e position corresponding to th e required ngular ositions, nd th e orresponding percentage o f axial illuminance fo r each osition s o un d ro m alibration curve of th e photocel l meter.

5J..2JL1.2 Method 8 — Collimator method.

T h i s method o f measuring relative i l lumination makes se f th e same pparatus nd techniques pecified n method . W it h h e lens to be measured se t up in th e apparatus, th e lens shall be rotated through th e desired field ngles nd h e hotocel l eadings compared with th e readings fo r th e lens on axis. h e ercentage f ight lux ransmitted an h en e ead ff alibration curve fo r th e photocel l system and converted to desired percentage i l luminance by dividing by cos« 0.

5.UL11.3 Method 9—Densitometric method. T h i s method o f measuring relative llumination makes use of th e same apparatus and techniques as specified in methods 5 an d 6 , except that a photographic plate is substi- tuted o r h e hotocel l when h e xtended source is used, an d fo r ehe integrating sphere

25

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MIL-STD-150A 12 May 999 when a collimator is used. In the latter case , the mage roduced by he ens hould be in harp ocus on he mulsion plane. The

exposures are made on the axis nd at the required angular positions ff axis. The ex- pr re imes hall e he am e t ll he pt «itions. h e densities of the xposed and d e -eloped images shall be measured and the relative- lluminance etermined sing he »ensitometric curve of the emuls ion , obtained jy exposing a calibrated step-wedge.

5.1.2.11.4 Method 10 — Indirect computa-

tion method. he ndirect omputation > f illuminance distribution from dimensions of

the ens re utlined n his ection. he m e t h o d in this case is for a lens while in the design stages, or in determining the lluminance distribution of an actual tons when no convenient photometric quipment s avail- «ble.

5.UM1.4.1 Distortionless lens with object

at nfinity. The case where the object s at infinity s applicable o most photographic objectives encountered in aerial and ground photography. The field angle of such ens is always xpressed y he obliquity angle

f, n the object pace. The esired elative illumination s given by:

R = cosV (17)

where E s he lluminance at he point n the image which corresponds to the obliquity angle * n he~vbject pace, nd E« s he illuminance at the center of the field. S < * > and So are, espectively, he eam ection areas of the oblique and axial beams at the chosen reference plane in the object space . The area S* will in general be smaller han S, d ue to vignetting, ut n ome nusual enses, * may be somewhat greater than S„ .

5.1.2.11.4.2 Distortionless en s with inite

object distance. The relative llumination R

can e ompute d ither n the object pace

or n he mage pace depending n wbu-h is more convenient The illuminance at anple 4 > is given by the integral':

E* = K/cos^dS = K'/cos^ dS' 18)

where K and K ' are onstants ndependent of obliquity. The ntegrals re o e aken ove r he espective ea m ections. h e n - tecrJs are necessary because f > n d * > ' vary from point to point over the beam ections. If the aperture is small, the integral becomes unnecessary and then:

E* - KS* < m < * = K ' S ' * cosV 19)

T h e elative llumination s hen ound y evaluating * nd „ or n blique d axial beam and talcing the ratio R = ^ > 2 < > .

& 1.2 .11 .4.3 Distorting ens with object at

infinity. This differs from the previous ay because the distortion will have onsider- able effect o n the distribution of illuminance expressed as a function of the entering obliquity angle *. n his ase the elative illu-

mination becomes:

E* S*

R = E.

f= in c o a +

h ' dh')

< d * ) (20)

S* and So are the areas of the beam sections for the oblique and axial be ams at the chosen reference plane in the object space; * is the obliquity angle n he object pace, s the focal ength of the ens nd ' s the mage height y measurements r omputations on he ens, elation an e stablished co.inecting h ' with 4. rom which he value of the derivative dh'/d* c an be f ound at any

desired point n he ield. For distortionless ens, ' = tan *; n hat pecial ase equation, (20) implifies o qua o n (17).

5.1.2J.1.4.4 Distorting ens with inite ob-

ject distance. The image space equations (18) or 19) o ld independent of the distortion of

9

9

SupMMda» Pas« « of 3 M ay M S 2«

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th e lens. f it s et.red o se h e at a f th e object space, equation 18) ecomes:

E0 co s4 ) S

(2 1)

(dh)

where K s onstant ifferent ro m h at used in equation 18), h is th e object height, an d h ' th e height o f th e image o f that object. T h e erivative h'/dh ust e ound y determining n lgebraic elationship e- tween h an d h ' . If th e aperture is sufficiently mall, will o t vary reatly ver h e beam ection nd h e quation m ay e e- duced to th e approximate form.

E* = K h ' dh')

S e >CO« 4 « >

(dh) (22) 5.1.2.11.4.5 Monocentric ens. n h e as e

o f a lens having a common center of curvature o ll h e urfaces nd oncentric image surface, th e relative i l lumination con-

tains only o ne cosine, namely:

R = E* S*

COSa> (2S) Eo

5.1.2.12 Resolving power. W h e n specifying o r measuring esolving ower, are hould be taken to consider th e fo l l owing pertinent factors: ethods f ests, ontrast f arget sed, in d f nd rocessing f photosensitive mulsion, hether ilter s o e used, nd magnification t which esolving

power target images re ead. Fo r reading resolution, agnification f h e owest power which permits convenient viewing will yield h e ighest esolution eadings. T h e rule ased n elwyn's xperiments2 h at

E. . Selwyn, National Bureau o f SUadavda Sie, 1W . 19M nd hotographic ournal M B, 1. M .

MIL-STO-150A 12 May 959

th e umerical alue f h e agnification should qual th e umber o f ines per millimeter xpected o e esolved an e o n-

sidered a rule o f thumb.) 5.1.2.12.1 hotographic esolving ower .

W h e n conducting photographic resolving power tests by r iethods 11 an d 12 , th e photosensitive material an d processing hould e in accordance v ith table II.

5.1.2.12.1.1 it. thod 11 — CoUimator method.*

1 Fo r lense? rimarily ntended o r use

on istant obje s, uc h s types , I. ll, an d V, this me hod should e used. T h e re - solving power irget is placed at th e princi-

pal o c u s f ollimator nd lluminated with white light. A filter o f a specified color m ay be used an d it shal l be placed between th e l ight source an d th e target It is recom- mended that , in order to eliminate vibration effects, a flash discharge lamp be used as th e l ight source nd h at h e ight ro m t e filtered f ecessary o pproximate white l ight. See .1.1.4.) xposure an e o n- trolled y means of eutral ensity ilters between th e l ight source and th e target T h e lens to be tested shall be placed in th e colli-

mated beam from th e target and a test plate o r film made in a series of f oca l settings as described in 5.15.1. Unless otherwise specified, h e en s hall e et t h e pecified T T i tt - r im i ii « elative perture. W it h h e es t plate perpendicular to th e optical axis o f th e lens, exposure shaP e made o f th e test tar- ge t t h e pecified ngular istance ro m th e xis ut o nd ncluding h e multiple o f h e pecified ngle alling earest h e corner of th e plate inside th e picture format T h e pecified ngle hould e multiples f 11 4 degrees an d should be spaced to provide 5 increments o r more in th e semi-field o f th e lens. h e xposure im e hal l e h e am e fo r ll ngular ettings nd hall e h e

u In ethod 1. f h e eaoWing ower a maa en T o d y a- t i oning ro m h a naa pe r mUliinater of h e target. XFL of th e oolUmator. nd FI> f h e ea t ane, he *ahia h o o l d e o r- rected by multiplying radial Unaa by th e meine of th e field engte an d angential iner y h e oe» f h e ield ngle.

Supersede« ag« 7 f 2 M ay 959 V

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MH.-STD-150A IS Mar •••

T A B L E I

L an atro* FhiHOMnltH» A SA tinihiiw—1> LM l wIml tiimiiii li i — (POM)

I

(70-mm. 1ormai lAuKhromati* aarial 10 f c o . * ao i tgmaBar)

(5-taeb format FaachromaH« —rial 80 LB .1 0 ft largar)

n (70-mm. f o r m a t rauahroiaat to arial 10 & 0 0.10

A small«*-); (tUindt format*

m

Panehroacttr aarial 80 IS ± .1 0

Pancbromati». aarial 50 os t uo IV Panchromat ic microfilm Maximnm contra** V > PuiwIiitHBatic (wmttoa pictara) HM O OA . ± .10 D C Panchromatic: portrait) 100 0.« .10

zn Banchromatio microfilm Maximum contraafc xm Panchromatic- microfilm Maximnm ontrast

HV BttMismritrf» racordinfr — IS, ± J . 0 ;

exposure im e w hich , give» h e highest solving power at th e angular setting nearest th e ngle qual o ne-half the half angle of view. T h e different angular Bettings-may be obtained by movingrthe lens« and: test plate about an axis near th e entrance pupil or by moving th e ollimators; r by means of series of collimators' placed in he correc t angular positions. h e en» m ay e tested with O r wi t ho ut the filter provided with it,

as required

5JiXSZ. tJS Metko& & — Target ange

method. For lenses primarily ntended or use at finite distances^ such as types IV , XHr

and X m > this method should be used; Also, it m ay be used, w h e n specified; or- testing other types of lenses; Properly i l luminated high contrast resolving power targets shal l be placed in th e object space in » plane per> pendicular to th e optical axis of the lens to be tested and spaced at the required angular distances. T h e distance from the lens to th e plane f h e argets hal l e esignated. W h e n h is method is used for testing lenses at nfinity o cus , ither ormula 12) n 5.1.1.» m ay be uaoä to determine the proper distance, r s om e esignated istance m ay be used T he test plate shal l be adjusted per-

pendicular to th e optical-axis of th e len&and exposed fo r maximum resolution at th e tart- get nearest h e ngle equal to ; one-hal f the half angle of view o f the lens being tested and shall be m ov e d in a aeries of f oca l settings s described in 5.1.2.1. T h e sensitized material , processing, etc., shal l be in accordance with table H .

5JL2J22 Method IS — Visual resolving

power. W h e n visual resolving power measurements; xe equired such s ype lenses),, they will be ma de exactly ike h e photographic resolving o wer testa* xcept that the aerial mage, when t s real nd easily vailable, ill e bserved isually under magnification. ethod 1 r 2 : n bM.y.Tg.f will be used as specified, epend- in* o n the use of the lenav W h e n the image formed by a viewfinder- (type X lens) s * virtual image, a telescope stopped d o w n to & millimeters.and placed at th e eye position w ül e sed to bserve the image. n his case, h e esolution ha l l be determined in terms of a pecified est har t at a pecified istance. n ll cases wher e th e mage is formed o n a ground glass, th e ground glass shal l be rer.ioved to observe th e aerial image, and th e image shal l be observed on a plane.

•

•

e

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addition o f this sUj enables o ne to measure prism ngle. W h e n measuring istortion at finite distances th e plane of th e targets must

be arallel o h e est late. Mathematica l means fo r adjusting th e measurements m ay be used to eliminate error from this source. If h e istortion s o e measured o r n object at a inite distance, th e targets shall be set up t th e required distance as specified. h e est rocedure s th e same as o r th e object at infinity, except that th e distortion s etermined n h e asis of paraxial o r calibrated magnification.

5J..2J.6.2 Method 6 — CoUimator ank method. T h i s method is intended fo r use with

lenses mounted ither in ameras o r in est barrels. Method 26 s similar to method 25 , except t ha t a bank of coll imators containing targets hal l e sed nstead f arget range.

5J.JZJ.6Ji Method S7 — Single coüimator photographic method. n o m e cases where high recision is no t required, single o l- l imator m ay be sed in onjunction with test plate as n method 6 . n h is method, either th e coUimator o r th e lens and th e test

plate shal l e rotated through th e equired field angles about th e center of th e entrance pupil of th e lens.

5.1.2.16.4 Method 28 — Nodal slide method. T h i s is a visual test method and m ay be used, wh en pecified, or lenses mounted n barrels. T h e lens to be tested shal l be properly placed n th e nodal slide of an optical test ench nd entered o h at ts ptical axis is nearly coinc ident with th e axis of th e microscope. Distortion for a particular angle shal l be measured by th e lateral displacement of th e observing microscope required to cen- te r h e arget at ac h ngular etting. At each ngle ß, h e microscope hal l e isplaced l ong ts orizontal xi s y th e distance f(1-cos /3)/cos ß a wa y from th e lens. T h i s refocusing is no t necessary if a flat field ba r is used. T o obtain th e value of distortion,

IS May f»

th e lateral distance through which th e microscope shal l be displaced must be divided y th e co sine of th e angle at which th e distortion

is eing measured. Because of inaccuracies present in most ptical benches, t is desir- able to make each measurement at th e same indicated angle o n each side of th e axis and to average th e tw o microscope readings o b- tained before computing distortion.

5.1.2.16.5 Method T9 — Goniometer method. T h i s is a visual method intended fo r use with enses mounted n ameras. A n ccurately calibrated test object o n glass, sually n h e o rm of cale r rid, hall e placed in th e plane of best definition f th e

lens to be tested and illuminated in a direction oward th e lens o be tested. h is test object must e iat, roperly entered, nd perpendicular o h e ptical xis. h e en s and illuminated test o bject shal l be placed in th e goniometer so that th e axis about wh i c h th e angles are measured passes through th e center of th e entrance pupil of th e lens. T h e telescope of th e goniometer shall be pointed at uccessive oints n h e test bject nd th e ield ngles etermined. T h e elescope «hall o t e efocused uring h e un f

measurements.) ro m U te oc a l ength of th e lens being tested and th e calibration of th e test object, th e angles subtended by th e various oints n h e est bject an e computed. Distortion then can e computed in terms of th e ifference n ngles n h e object id e nd mage ide; h is istortion in turn an e converted nto th e tandard f orm . See 5.L2JS.) By adjusting th e f o cus of h e elescope, h is ethod an e x- panded o nclude o m e cases n w hi c h th e test bject, is n lane orresponding o some inite magnification. ar e hould e exercised o nsure hat h e o ne of ight from th e test lens is included in th e entrance pupil of th e telescope.

5.1.2.16.6 Method S O — Projection method. T h i s method s ntended rimarily or testing projection lenses. A test object simi-

8/14/2019 Mil Std 150a


MH-Sm-150A \2 May tSt

la r o h e ne s < d n method 9 hal l e placed n h e object plane of th e lens to be tested an d projected onto a suitable screen. Measurements shal l be made of th e projected

imafe of the teat object T h e distortion shall be computed in terms o f th e tea? object Care should be taken to insure t h a t tl e screen and test object re erpendicular t . » h e ptical axis of h e en s nd that th e est object s flat an d properly centered. T h e cone o f l ight 'rom h e rojection am p hal l ompletely .1 1 h e rojection ens, nd ie est bject

shaiJ e niformly Uuminated h e ign of distortion s eversed ro m heory n ro - jection hrough lens nd measured a h e long conjugate.

5.1X16.7 Tangential distortion. Any of th e si x methods fo r measuring radial distortion m ay be modified o measure angential is- tort ion y onsidering h e isplacement of image points perpendicular to a radius from th e enter f h e ield. h e magnitude f tangential distortion varies from zero along o ne diameter to a maximum along an orientation 0 egrees o h e iameter f ero distortion. herefore, h en equired, angential distortion thal l be measured fo r tw o axial orientations cf th e lens, and th e orien-

tation r maximum angential istortion computed.

5.1X17 rism ffect. o easure h e prism ffect n erms f h in quivalent prism f vertex angle a, use is made o f th e fac t h at blique ays re eviated y h e prism mor e than, and in th e same direction as, h e xial ay. n ssumption s made t h a t th e axial ray makes only a small angle with th e normal to th e surface of th e prism (o r th e prism m ay be assumed to be in th e minimum deviation for th e axial ray). If th e camera nder est s sed o hotograph three ol l imators r istant argets, ne axial nd h e ther two making angles +ß an d — ß with h e xis, h e istances ro m th e O egree mage o h e -/5 mage nd from th e 0 egree image o th e — ß image

Supme*M Pag« 4 of * M ay tS9

are ifferent n h e resence f rism effect h is ifference s measured n h e negative. Under h e ssumptions made, h e analytical xpression fo r this ifference s:

A

[tan ß ) — an ß — ) — an .] (26)

where f is th e equivalent focal length of th e lens, s h e eviation of h e ay making ß with h e axis within lose approxima- tion h e eviation s h e am e o r -/3 nd —ß), nd „ /2 s h e eviation f h e axial ay . Tables fo r A can be computed fo r various values f f, ß, an d a. T h e measured and tabulated values o f A are compared, an d th e corresponding a is valuated.

5.1.2.18 Spherical aberration.

5.1X18.1 Method SI — Annual ing or Hartmann disk method. W h e n spherical aberration is specified in terms o f change in foca l position o r zones f different radii, Hartmann disk a plate covering a f ront of th e en s vith oles t h e ifferent ones) o r aperture c c isisti ng o f open annular rings will be placed ve r th e front of th e lens an d properly centered. Either a photographic or visual method o f determining th e difference in foca l positions fo r different zones m ay be used. Various modifications f hese meth- o ds nd ther methods ay e mployed, such as knife-edge test or interf e*.ometric method. W h e n measuring pherical berration or n bject t nfinity, h e arget w hi c h s maged y h e ea t en s m ay e placed in a col l imator or a distance at least 25 imes h e o ca l ength of h e en s o * tested.

5.1X18.2 Method S2 — Stopped-aperture

method. W h e n spherical aberration is specified n terms of h e ifference etween h e best f o cus at maximum perture nd t designated educed perture, oda l lide optical ench o r n utocoll imation method m ay e sed to etermine th e i fference n

•

•

34 it u . & wmmmo t T nt umm ontc i i OT-rovoao/HM«

8/14/2019 Mil Std 150a


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ASD/ENYES Wright-Patterson AFB OH 45433

8/14/2019 Mil Std 150a


STANDARDIZAT ION DOCUMENT IMPROVEMENT PROPOSAL 1 . OOCUMCN T NUMMM X OOCUMCNT TITIA 3a NAMI OP 8USMITTINO OROANI2ATION

h . Aoontmjttmit. city, M a*, air c«a*j

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8/14/2019 Mil Std 150a


NOTICE OF VALIDATION INCH-POUND

MIL-STD-150A NOTICE 3 15 November 1993

MILITARY STANDARD PHOTOGRAPHIC LENSES

MIL-STD-150A dated 28 January 1963 has been reviewed and determined to be valid for use in acquisition.

Custodians: Army ER Navy AS Air Force 99 Reviewers: Army MI DLA GS User Activities: Army GL ME

Preparing Activity: Air Force - 70