UnderstandingExposure

Theexposuretriangleandit’scomponents

The3componentsofexposure

• Aperture• Shu9erspeed• ISO(ASA)

Defini@ons

•  Apertureisthedensityoflightenteringthecamera.

•  Shu9erspeedisthe@metheshu9erisexposingthefilmplanetolight.

•  ISOisthesensi@vitytolightoftheFilmorsensor.

Sowhatdotheymean!Aperture

•  Apertureisthesizeoftheholeproducedbytheapertureblades.

•  ItisnormallydefinedinFstops.•  i.e.normallyfromf1.2tof32•  Thefnumberisafrac@on.•  Thereforewitha50mmlensa25mmdiameterholeisf2.Witha500mmlensa125mmholeisonlyf4!

Shu9erSpeed

•  Shu9erspeedisnormallymeasuredinsecondsorfrac@onsofseconds.

•  i.e.normallyfrom8sto1/8000s!•  Longexposuresarenormally1/4sorlonger•  Shortorquickexposuresarenormally1/500sorless!•  Camerashakehappenswhenyouuseashu9erspeedlongerthanthethefocallengthofthelens.

•  i.e.witha50mmlenshandheldlongerthan1/50sor1/60sistherule.

ISO(ASA)

•  Thesensi@vityofthefilmorsensor.•  NormallyIS0100to6400(100,500NOW!)•  Thelowerthenumberthelesssensi@vethecameraistolight.Thehigherthemore.

•  i.e.ISO100needslotsoflight/sun.ISO12800canbeusedinadarkroom.

•  ThehighertheISO,themoregrain/noise.

Whatdotheydo?

•  Apertureeffectstheamountoflightenteringthecameraandthedepthoffield(DOF).

•  Shu9erspeedeffectstheamountofmo@onrecorded.

•  ISOeffectsthesensi@vityofthecameratolightandtheamountofgrain/noiseproduced.

Depthoffield(DOF)

•  Thisisdefinedasthedistanceofobjectsinfocus.

•  i.e.whetherjusttheobjectisinfocusortheforegroundandbackgroundareinfocustoo!

•  AshallowDOFiswherejusttheobjectisinfocus.(UsedinPortraits)

•  AdeepDOFiswheretheforegroundandbackgroundareinfocus.(UsedinLandscapes)

Mo@onBlur

•  Mo@onbluristheamountofmo@onshowninthephoto.

•  i.e.capturingananimalrunningorwaterflowinginariver.

•  Ahighshu9erspeed“freezes”anobject.•  Asloworlongshu9erspeedcreatesasenseofmo@onintheobjecti.e.Water.

Highshu9erspeed1/1000s

Slow/Longshu9erspeed4s

GrainorNoise.

•  Grainornoiseistheamountofspecklesordiscolouringontheedgesofobjects.

•  InFilm,Grainisnormallysceneasspeckleddots.Digitallyitproducesdiscoloura@onontheedgesofobjects.

•  100ISOhasfinegrainorlownoise,3200ISOandabovehasharshgrainorhighnoise.

Gedngtherightexposure.

EverythingyouadjustseffectstheExposure!

ModesonyourCamera

ProgramMode:Automa@callyadjustsApertureandShu9erspeedwithafixedISOShu9erPriority:Automa@callyadjustsAperturewithafixedShu9erspeedandISOAperturePriority:Automa@callyadjustShu9erspeedwithafixedApertureandISOManual:ApertureandShu9erspeedmustbeadjustedaccordinglywithafixedISO

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