Quick snap guide to lighting

DAVID BUSCHS QUICK SNAP GUIDE

TO LIGHTINGDavid D. Busch

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David Buschs Quick Snap Guide to LightingDavid D. Busch

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For Cathy, who continues to be the light of my life.

David Busch's Quick Snap Guide to Lighting

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Acknowledgments

Once again thanks to the folks at Course Technology, who have pioneered publishing digital imagingbooks in full color at a price anyone can afford. Special thanks to executive editor Kevin Harreld,who always gives me the freedom to let my imagination run free with a topic, as well as my veteranproduction team including project editor Jenny Davidson, and technical editor Mike Sullivan. Also thanks toMike Tanamachi, cover designer; Bill Hartman, layout; and my agent, Carole McClendon, who has theamazing ability to keep both publishers and authors happy.

About the Author

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About the Author

W ith more than a million books in print, David D. Busch is one of the best-selling authors ofbooks on digital photography and imaging technology, and the originator of popular series likeDavid Buschs Pro Secrets and David Buschs Quick Snap Guides. He has written seven hugelysuccessful guidebooks for Nikon digital SLR models, and six additional user guides for other camera models,as well as many popular books devoted to dSLRs, including Mastering Digital SLR Photography, SecondEdition and Digital SLR Pro Secrets. As a roving photojournalist for more than 20 years, he illustrated hisbooks, magazine articles, and newspaper reports with award-winning images. Hes operated his own com-mercial studio, suffocated in formal dress while shooting weddings-for-hire, and shot sports for a daily news-paper and upstate New York college. His photos have been published in magazines as diverse as ScientificAmerican and Petersens PhotoGraphic, and his articles have appeared in Popular Photography & Imaging,The Rangefinder, The Professional Photographer, and hundreds of other publications. Hes also revieweddozens of digital cameras for CNet and Computer Shopper.

When About.com named its top five books on Beginning Digital Photography, debuting at the #1 and #2slots were Buschs Digital Photography All-In-One Desk Reference for Dummies and Mastering DigitalPhotography. During the past year, hes had as many as five of his books listed in the Top 20 ofAmazon.coms Digital Photography Bestseller listsimultaneously! Buschs 100-plus other books publishedsince 1983 include bestsellers like David Buschs Quick Snap Guide to Using Digital SLR Lenses. He is amember of the Cleveland Photographic Society, which has been in continuous operation since 1887, andcan be located at www.clevelandphoto.org.


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Contents

Preface................................................................................................xIntroduction ........................................................................................xi

1 Basics of Good Lighting and Exposure ..................................................1High-Contrast Lighting .........................................................................................2Low-Contrast Lighting...........................................................................................4High-Key Lighting................................................................................................6Low-Key Lighting .................................................................................................8Light and the Exposure Triangle ..........................................................................10F/Stops ...........................................................................................................12Shutter Speeds..................................................................................................14

Focal Planes and Shutter Speeds.................................................................14Adjusting Exposure with ISO Settings ..................................................................18

2 Optimizing Exposure .........................................................................21Metering Modes ...............................................................................................22

Evaluative/Matrix .....................................................................................22Partial......................................................................................................22Spot ........................................................................................................22Center-Weighted .......................................................................................23Averaging................................................................................................23

Aperture Priority ...............................................................................................24Shutter Priority ..................................................................................................26Programmed Exposure Modes ............................................................................30Manual Exposure..............................................................................................32Adjusting Exposure/EV......................................................................................34Bracketing .......................................................................................................36Histograms.......................................................................................................38Gray Cards, Light Meters, and Do-It-Yourself Exposure...........................................40

Contents

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3 Available Light ..................................................................................43White Balance .................................................................................................44

Manual White Balance..............................................................................46Creating Your Own White Balance Settings .................................................47

Color and Mood...............................................................................................48Filling in Shadows.............................................................................................52Using Reflectors ................................................................................................54

White Poster Board ...................................................................................54Foam Board .............................................................................................54Aluminum Foil...........................................................................................55Mylar Sheets ............................................................................................55Auto Sunscreens .......................................................................................55Umbrellas ................................................................................................56Black Cardboard or Cloth ..........................................................................57

Polarizing Filters ...............................................................................................58Polarizers and Wide-Angle Lenses...............................................................60

Lighting and the Sky..........................................................................................62Using Graduated Neutral Density Filters ......................................................64

4 Electronic Flash Fundamentals ............................................................67How Flash Works..............................................................................................68Types of Portable Electronic Flash........................................................................70

Built-in Flash .............................................................................................71Add-on Flash ............................................................................................73Studio Flash..............................................................................................73

Using Flash Creatively .......................................................................................74Bounce Flash ............................................................................................74Flash on a Bracket.....................................................................................76Off-Camera Flash......................................................................................77Multiple Flash ...........................................................................................77Paint with Light .........................................................................................77


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Determining Exposure........................................................................................78Automatic TTL Flash Exposure .....................................................................78Guide Numbers ........................................................................................79Flash Meters .............................................................................................79

Choosing a Flash Sync Mode.............................................................................80Ghost Images ...........................................................................................81High-Speed (FP) Sync ................................................................................83

Studio Flash .....................................................................................................84Fill Flash ..........................................................................................................88

5 Using Portrait Lighting Tools ...............................................................91Soft Lighting and Distance..................................................................................92Balancing Light.................................................................................................94

The Inverse Square Law .............................................................................94Using Lighting Ratios .................................................................................94

Using a Main Light............................................................................................98Fill Light .........................................................................................................100Other Lights ...................................................................................................102

Background Light ....................................................................................102Hair Light ...............................................................................................102Reflectors ...............................................................................................103

Umbrellas ......................................................................................................104Soft Boxes......................................................................................................106

Strip Lights .............................................................................................108

6 Portrait Lighting Techniques..............................................................111Lighting Setup Basics .......................................................................................112Split Lighting ..................................................................................................114Side/Profile Lighting........................................................................................116

Backlighting ...........................................................................................11745-Degree Lighting .........................................................................................118Short Lighting .................................................................................................120

Contents

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Broad Lighting................................................................................................122Butterfly Lighting .............................................................................................124Rembrandt Lighting .........................................................................................126

7 Lighting and Action..........................................................................129Indoor Lighting ...............................................................................................130Fast Shutter Speeds .........................................................................................132Slow Shutter Speeds........................................................................................136Outdoor Lighting.............................................................................................140Flash or Existing Light? ....................................................................................144

8 Close-up and Macro Lighting............................................................147Lighting Challenges.........................................................................................148Magnification and Perspective..........................................................................150Working with Existing Light ..............................................................................152Working with Electronic Flash...........................................................................154Working with Continuous Lighting.....................................................................156High- and Low-Contrast Close-ups .....................................................................160Tent Lighting ...................................................................................................162

9 Travel and Architecture ....................................................................165Choosing the Best Light and Best Angle .............................................................166Monuments and Museums................................................................................168Interiors .........................................................................................................170Mixed Illumination ..........................................................................................174Sunsets and Sunrises .......................................................................................176Night Lighting ................................................................................................178Fireworks .......................................................................................................182Water, Beaches, and Snow..............................................................................184

Glossary .........................................................................................188

Index ..............................................................................................196

Introduction

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Preface

Youve mastered your digital SLR (mostly), used it to create a few thousand photographic master-pieces, and now you are looking to add some skills in the use of light in all its wondrous varieties.But, you have some questions. How do I create and work with diffuse light? How can I tame day-light so that my pictures dont look harsh and overexposed? What is the secret to working with multiple lightsources? What accessories and equipment will help me use light most creatively? What is color temperature?You dont want to spend hours or days studying a comprehensive book on digital SLR photography. All youwant at this moment is a quick guide that explains the purpose and function of each type of lighting, how touse it to create great-looking pictures, and how to improve the lighting you find in a scene. Why isnt there abook that summarizes whole collections of these concepts in a page or two with lots of illustrations showingwhat your results will look like when you use this type of lighting, or that?

Now there is such a book. If you want a quick introduction to working with light and exposure, improvingyour photos with filters and reflectors, or transforming good lighting into great lighting, this book is for you.Once you realize that light is the tool you use to paint your photographs, you need this Quick Snap Guide.

Im not going to tell you everything there is to know about using your digital SLR camera; Im going to tellyou just what you need to get started using light effectively to take compelling photos that will amaze yourfriends, family, colleaguesand yourself.


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T his is the fourth book inmy Quick Snap guide-book series, each ofwhich takes a single puzzlingarea of digital photography andcondenses each concept into afew pages that explain every-thing you need to know in easy-to-absorb bullet points, someessential text that summarizes justwhat you absolutely need toknow, and is clearly illustratedwith a few compelling photo-graphs. Previous books in thisseries have dealt with point-and-shoot and digital SLR cameras,and the selection and use of inter-changeable lenses. This one isdevoted entirely to the mysteriesof light.

Like all my Quick Snap guides,this book is aimed at photogra-phers who may be new to SLRs ornew to digital SLRs, and are over-whelmed by their options whileunderwhelmed by the explana-tions they receive in most of thephotography books available.

The most comprehensive guide-books try to cover too much mate-rial. Youre lost in page afterpage of background and descrip-tions, most of which youre notreally interested in. Books of thistype are great if you alreadyknow what you dont know, andyou can find an answer some-where using voluminous tables ofcontents or lengthy indexes.

The book is designed for thosewhod rather browse their waythrough a catalog of ideas andtechniques, arranged in abrowseable layout. You canthumb through and find the exactinformation you need quickly. Allthe basics of light and lightingtechniques are presented withintwo-page and four-page spreads,so all the explanations and theillustrations that illuminate themare there for easy access. Thisbook should solve many of yourproblems with a minimum amountof fuss and frustration.

Then, when youre ready to learnmore, I hope you pick up one ofmy other in-depth guides to digi-tal SLR photography. They areoffered by Course Technology,each approaching the topic froma different perspective. Theyinclude:

Quick Snap Guide to Digital SLR PhotographyIf youre new to digital SLRs, thisbook belongs in your camerabag as a reference, so you canalways have the basic knowledgeyou need with you, even if itdoesnt yet reside in your head. Itserves as a refresher that summa-rizes the basic features of digitalSLR cameras, and what settingsto use and when, such as continu-ous autofocus/single autofocus,aperture/shutter priority, EV set-tings, and so forth. The guidealso includes recipes for shootingthe most common kinds of pic-tures, with step-by-step instruc-tions for capturing effective sportsphotos, portraits, landscapes,and other types of images.

Daivd Buschs Quick Snap Guideto Using Digital SLR LensesLike this book, my lens guide con-centrates on a single set of top-icschoosing and using lenses. Ifyoure ready to go beyond thebasics but are unsure which inter-changeable lens or two to buy,and, more importantly, how andwhen to use them, this bookoffers focused, concise informa-tion and techniques. It includesoverviews of how lenses work,and which types are available,discussions of all lens controlsand features, including image sta-bilization/vibration reduction,and how to select the best lensand settings for particular typesof photos.

Introduction

Introduction

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Mastering Digital SLRPhotography, Second EditionThis book is an introduction todigital SLR photography, withnuts-and-bolts explanations of thetechnology, more in-depth cover-age of settings, and whole chap-ters on the most common types ofphotography. Use this book tolearn how to operate your dSLR and get the most from its capabilities.

Digital SLR Pro SecretsThis is my more advanced guideto dSLR photography with greaterdepth and detail about the topicsyoure most interested in. Ifyouve already mastered thebasics in Mastering Digital SLRPhotography, this book will takeyou to the next level.

Should you need instruction onhow to get the most from specificcamera models, look for myCourse Technology books for themost recent cameras introducedby Nikon, Canon, Pentax, Sony,and other vendors under theDavid Buschs Guides to DigitalSLR Photography banner. You canfind more information about thosebooks at www.nikonguides.comand www.dslrguides.com.

Who Am I?After spending many years as theworlds most successful unknownauthor, Ive become slightly lessobscure in the past few years,thanks to a horde of cameraguidebooks and other photo-graphically-oriented tomes. Youmay have seen my photographyarticles in Popular Photography & Imaging magazine. Ive alsowritten about 2,000 articles formagazines like Petersens Photo-Graphic (which is now defunctthrough no fault of my own), plusThe Rangefinder, ProfessionalPhotographer, and dozens ofother photographic publications.But, first, and foremost, Im aphotojournalist and made my liv-ing in the field until I begandevoting most of my time to writ-ing books. Although I love writ-ing, Im happiest when Im outtaking pictures, which is why Itook 14 days late last year for asolo visit to Spainnot as atourist, because Ive been toSpain no less than a dozen timesin the pastbut solely to take

photographs of the people, land-scapes, and monuments that Ivegrown to love.

Over the years, Ive worked as asports photographer for an Ohionewspaper and for an upstateNew York college. Ive operatedmy own commercial studio andphoto lab, cranking out productshots on demand and then print-ing a few hundred glossy 8 10s on a tight deadline for apress kit. Ive served as a photo-posing instructor for a modelingagency. People have actuallypaid me to shoot their weddingsand immortalize them with por-traits. I even prepared press kitsand articles on photography as aPR consultant for a largeRochester, N.Y., company, whichshall remain nameless. My trialsand travails with imaging andcomputer technology have madetheir way into print in book forman alarming number of times,including a few dozen on scan-ners and photography.

Like you, I love photography forits own merits, and I view technol-ogy as just another tool to helpme get the images I see in myminds eye. But, also like you, Ihad to master this technologybefore I could apply it to mywork. This book is the result ofwhat Ive learned, and I hope itwill help you master your NikonD60 digital SLR, too.

As I write this, Im currently in thethroes of upgrading my mainwebsite, which you can find atwww.dbusch.com, adding tutori-als and information about myother books. Theres a lot of infor-mation about several differentcamera models right now, but Illbe adding tips and recommenda-tions about newer models and alist of equipment and accessoriesthat I cant live without in the nextfew months. I hope youll stop byfor a visit.

U nless youre extraordinarily lucky, or supremely observant,great lighting, like most things of artistic value, doesnt hap-pen by accident. Its entirely possible that youll randomlyencounter a scene or subject thats bathed in marvelous lighting, illu-mination that perfectly sculpts an image in highlights and shadows.But how often can you count on such luck? Ansel Adams is oftenquoted as saying (although he probably didnt) that The harder Iwork, the luckier I get.

The great photographer was known for his patience in seeking out thebest lighting for a composition, and he did actually say, A good pho-tograph is knowing where to stand. My own take on excellence inillumination is that you have to possess the ability to recognize effec-tive lighting when it is already present, and have the skill to manipu-late the light when it is not.

This chapter will launch you down the road to being able to use thelight that is present, manipulate it when necessary to achieve theeffects you want, and to create good lighting from scratch using thetools available. Im going to present some basic lighting concepts thatyou can use right now and apply with the more advanced informationpresented in later chapters.

Basics of Good Lightingand Exposure1


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High-Contrast LightingTo be able to use good lightingyourself, you have to be able torecognize it when you see it.There is a great story about pho-tographer George Krause spend-ing the early part of his careershooting photographs only onovercast days, under diffuse, low-contrast illumination (illustrated inthe next section). That kind oflighting can be exceptionallychallenging, because there is nointerplay of highlights and shad-ows to add depth to a composi-tion. Only when Krause wasconvinced that he understood softlighting did he move on to workwith more dramatic applicationsof light. No example of my ownin this book could illustrate theidea of good lighting morevividly than Krauses Shadow,taken in Seville, Spain more than 40 years ago. I urge you to check it out atwww.georgekrause.com/shadow.htm. Does the photoshow an old womanor an oldwoman followed by a darksecret?

High-contrast lighting is illumina-tion that provides images thatoffer stark, brightly lit highlightsand dark, inky shadows, with rel-atively few tones in the middle.Such images are seen as espe-cially dramatic, because theycapture the eye, drawing atten-tion to the bold and strongshapes within the frame. High-contrast photos are oftenseen as dynamic, in the sense

that something is going on in thepicture, when compared toimages that have less contrastand are seen as flat and static.

Today, high-contrast photos aresometimes considered bad form,because digital photographersmust constantly battle to over-come sensors that cant alwaysrecord the full range of tones in ascene and, instead, produce

images with an excessive amountof contrast. In truth, its onlyunwanted contrast thats bad.Indeed, back at the beginning ofmy career in the days of film anddarkrooms, one of the most popu-lar tools was high contrast lith(lithographic) film, which couldproduce nothing but black-and-clear images. Another favoritewas extra contrasty photographicpaper, like the legendary Agfa

Figure 1.1High-contrast lightingemphasizes textureand detail.

Basics of Good Lighting and Exposure

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Brovira #6, which was, in thosepre-Spinal Tap days, the equiva-lent of being able to turn youramp up to 11.

High-contrast lighting does anumber of things for you.

It can brighten up low-contrast sub-jects and make them more vibrantand interesting.

It can take images of normal con-trast and give them a bold look.

It can salvage images that arealready excessively high in con-trast.

It emphasizes texture and detail.

It can be used to provide a unifiedlook among several images thatdiffer in contrast, by pegging themall to the high contrast end.

In portraiture, higher contrast light-ing can give male faces a rugged,masculine look, and, if used inmoderation, accentuate characterlines in older people.

High-contrast lighting emphasizestexture, as you can see in Figure1.1. Because of the shadows castby the sunlight, each detail of thecathedral stands out in vividrelief. This type of lighting ishighly directional. It illuminatesthe subject from a well-definedsource that is relatively narrow,and the beam of light doesntspread much, which is the sourceof the deep, sharp-edged shad-ows. The built-in flash unit onyour camera often produces illumination of this sort. High-contrast lighting is generallydirect, and at some distance fromthe subject; indeed, the fartheryou move a light source from asubject, the more harsh andsharp it becomes. Later in thisbook, Ill show you how to createhigh-contrast lighting when youneed it, and how to correct for itwhen you dont. Figure 1.2shows the results of a typical highcontrast lighting setup.

Figure 1.2 High-contrast illumination produces deep, sharp-edgedshadows.

Figure 1.3

HOW ITS LITThe clown figurine shown in Figure 1.2 was lit with a singledirect light from the right side, as pictured in Figure 1.3. No

fill-in light was used to illuminate the shadows, other than light that mighthave bounced back from the surrounding areas.


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Low-Contrast LightingLike high-contrast lighting, thelow-contrast variety isnt inher-ently bad; its inherently different.This kind of lighting is also calledsoft or diffuse illumination,because it provides a gentle, sub-tle, sometimes moody look to thesubject matter.

With low-contrast lighting, thereare few or no shadows, andthose that exist have soft edges.The entire subject is washed witha non-directional light that seemsto come from every angle. Diffuselighting almost always is pro-duced by the use of reflectors tosoften and spread the illuminationbefore it is bounced toward yoursubject; or by passing the lightthrough some sort of translucentmaterial, such as the fabric of awhite umbrella, or the diffusionscreen of a soft box. As youmove a light source closer to asubject, its illumination tends towrap around the subject andprovide more even lighting.Move the source farther from thesubject, and it becomes moredirectional and gains contrast.

There are several things low-contrast lighting can do for you.

It can soften high-contrast subjectsand make them more subdued.

It can take images of normal con-trast and give them a moody look.

It can partially recover images ofsubjects that are excessively highin contrast.

Like high-contrast imaging, it canbe used to provide a unified lookamong groups of pictures that dif-fer in contrast by giving them all asofter look.

It masks details, which can be use-ful in portraiture, where soft light-ing hides skin flaws, provides amore glamorous or romantic lookto photos of female subjects, andoffers a gentler rendition of olderpeople who would prefer to down-play the ravages of time.

Figure 1.4 Overcast days produce low-contrast images with muted colors.


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One thing to keep in mind is thatit is possible to combine low-contrast lighting in the same photograph, to good effect. Forexample, you can shoot a humansubject outdoors in the soft, dif-fuse lighting in the shade of atree, with the background illumi-nated by harsh direct sunlight.The contrast between the two canhelp separate your main subjectfrom the background and providean interesting look.

Youll often encounter low-contrast lighting outdoors oncloudy and overcast days, orthose plagued by haze or fog, asshown in Figure 1.4. Notice thatin this view of Paris, colors aremuted, too; low-contrast lightingtends to produce desaturatedhues. Back in the pre-digitaldays, photographers would use

films noted for their vivid colors,such as Kodak Ektachrome orFujifilm Velvia; today, you cansimply boost the saturation settingof your digital camera.

Figure 1.5 shows a typical low-contrast lighting arrangement.The shadows are minimal, whichreduces the three-dimensionallook of the porcelain figurinecompared to the high-contrastimage in the previous section.Note that the shadow areas aresubdued, but not eliminatedentirely. Low-contrast lighting canbe used to soften subjects, butshouldnt be carried to extremes.Without any shadows at all, thefigurine would look flat and two-dimensional. Ill show you anexample of a shadowless imagein the next section. Figure 1.5 Low-contrast lighting softens the shadows.

Figure 1.6

HOW ITS LITIn this case, the clown was lit with a pair of umbrellas locatedin front of the figurine and at about a 45-degree angle from the

lens axis, as shown in Figure 1.6. The left umbrella was moved slightly far-ther back, and set to 3/4 intensity so the shadows cast by the other umbrellawerent completely filled in. If your light source cant be varied in intensity,just move it back a bit more to reproduce this effect. Note that the light bulbsshown are modeling lights that preview the lighting effect of the flash.


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High-Key LightingAnother illumination concept youneed to understand is the differ-ence between high-key and low-key lighting. Its easy to get thesestyles of lighting confused withhigh-contrast and low-contrasttypes, and adding to the confu-sion is the reality that high-keyimages are relatively low in con-trast, while low-key images canbe high in contrast. Whats going on here? Ill explain eachtype in this section and the onethat follows.

High-key lighting is bright. Whenan image is photographed in ahigh-key style, it is typically verybright, with lots of white tones.The darkest areas may actuallyfall in what is considered a mid-dle tone area, and there aremaybe no dark shadows at all,as you can see in Figure 1.7,which has almost no blacks.Because all the tones are rela-tively homogenous, high-key light-ing can be considered relatively

low in contrast. But, as youvelearned, not all low contrastimages are bright; a photo canconsist of predominantly middletones or dark tones and still beconsidered low contrast. Whatdistinguishes all kinds of low con-trast images is the restricted tonalrange. High-key photos are justone type of reduced contrastimage.

High-key lighting became popu-lar at the beginning of the filmand television eras, because nei-ther medium was able to capturescenes of high contrast.Originally, a rather clumsy three-light scheme was used, with atrio of fixtures illuminating eachperson in a scene (to the left,right, and middle). That produceda bright, uniform lighting patternwith no shadows. In addition toreducing the contrast of the shotso it was easier to photographtechnically, high-key lighting wasfast to set up, and allowed film

Figure 1.7 High-key images have a preponderance of light tones,with few true blacks.


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and television production to com-plete more scenes in less time.Still photographers generally usemore sophisticated lightingarrangements to produce high-key effects (its unlikely that youllwant to bathe each subject inyour photo with their own triad oflights), but the same generalbright, upbeat, virtually shadow-less illumination scheme is used.

Figure 1.8 shows a high-keyimage. Compared to the low-contrast image in the previoussection (Figure 1.5), this one hasvirtually no shadows; all the tonesin the picture fall into the light tomiddle-tone range.

Figure 1.8 High-key lighting produces a flat, often shadowlessimage.

Figure 1.9

HOW ITS LITThe clown figurine shown in Figure 1.8 was lit with a pair oflights of equal intensity bounced into umbrellas set at roughly

45-degree angles from the lens axis, as shown in Figure 1.9. This pro-duces a soft, even lighting with virtually no shadows, especially whencombined with light bouncing back from the light-colored background.

LIGHTING RATIOSA lighting ratio is a comparison between the level of illumination of thehighlight areas of an image, and the amount of light falling into the shad-ows. For example, if an exposure of 1/500th second at f/11 is requiredto properly expose the highlights of an object, while the shadows wouldrequire an exposure of 1/500th second at f/5.6, then the lighting ratiowould be 3:1. High-key images often have a ratio of 2:1 or even 1:1,while low-key images can produce ratios of 8:1 or higher. Ill explain lighting ratios in more detail in Chapter 5.


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Low-Key LightingLow-key images are typically verydark, and often are illuminatedby a single light source that pro-vides dramatic highlights, whileallowing the rest of the image tofade to darkness. A low-keyimage is often high in contrast,but some can include shadowareas that are illuminated with afill-in (fill) light, so there is detailin the dark areas, creating aneffect that artists call chiaroscuro(Italian for light-dark). If youremember that low-key photosare always dark (sometimes evenmurky), you can differentiatethem from the broader categoryof high-contrast images.

The scene in Figure 1.10 shows acathedral as seen from an alley-way opposite. The cathedralstower is illuminated by flood light-ing, while the alley has severalstreet lamps to dimly light the nar-row passage. This lighting cre-ates a dramatic mood for thepicture, which was taken at mid-night on a crisp October day.You can see the same scene fromroughly the same vantage point

at 6 a.m. the following day inFigure 1.11. The early morninglight is still fairly high in contrast,but the foreboding low-key effectis gone.

Low-key lighting is another off-shoot of the film and television

area, and became popular ratherearly, despite the technical limita-tions imposed by high-contrastscenes, because more dramaticlighting was needed for seriousdrama, film noir, horror, andother heavier fare. Where high-key lighting illuminates the entire

subject evenly, low-key lightingemphasizes the contours of a per-son or object by providing lightonly to the edges, while allowingother areas to fall into shadow,as you can see in Figure 1.12.

Figure 1.10Low-key lightingcreates a moodyeffect.


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Figure 1.12 Low-key lighting often uses only a single light source,with the shadows filled in by reflected light.

Figure 1.13

HOW ITS LITThe clown figurine shown in Figure 1.12 was lit with a singledirect light from the right side, as pictured in Figure 1.13.

No fill-in light was used to illuminate the shadows, other than light thatmight have bounced back from the surrounding areas and the umbrellaused as a reflector.

Figure 1.11 The same scene shot by early morning light has a brighter look.


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Light and the Exposure TriangleAn integral part of using lightingcorrectly is achieving the correctexposure, so that the final imagehas the tonal values you want toaccurately (or imaginatively) rep-resent your subject. Three compo-nents of the camera, the shutterspeed, lens opening (or aperture),and sensor sensitivity (measuredin ISO values), determine theexposure for a given scene. Thesethree aspects that involve yourcamera, its mechanics, and

controls are known as the expo-sure triangle, shown in Figure1.14.

Shutter speed. This is the lengthof time that the sensor is effectivelyexposed to light. I say effectively,because, at briefer shutter speeds,the entire sensor may not beexposed all at one time; the cam-era may use a traveling slit toexpose only a small section of thesensor at a time. In addition, elec-tronic flash has a duration thatsshorter than the amount of time the

shutter is completely open, so that,even though your camera is set for1/200th second, the sensor maybe effectively exposed for only the1/1,000th second duration of theflash.

Aperture. The aperture repre-sents the quantity of the light that isallowed to pass through the lens tothe sensor, much like garden hosesof different diameters allow moreor less water to flow during a giventime period.

ISO. This is the relative sensitivityof the sensor. Each camera has abase sensitivity, which is its lowesttrue ISO setting. It can then pro-duce higher (or even lower) ISOsensitivities by amplifying (ordeamplifying) the signal as pho-tons are captured.

The three components of theexposure triangle work propor-tionately and reciprocally to pro-duce an exposure. That is, if youdouble the amount of light thatsavailable, increase the apertureby one stop, make the shutterspeed twice as long, or boost theISO setting 2X, youll get twice asmuch exposure. Similarly, youcan increase any of these factors

while decreasing one of the others by a similar proportion tokeep the same exposure.

There are six aspects that affectlight as it travels from its source toyour sensor. The six factors thatinfluence the light we use to takephotos are as follows:

Light source. The most importantattribute of light is its intensity. Howbright is the light at its source? Aslight grows more intense, it allowsusing exposures that have fastershutter speeds, smaller apertures,reduced ISO settings, or some com-bination of the three. Lower lightlevels mandate slower shutterspeeds, larger apertures, andhigher ISO settings, all of whichcan have negative effects on ourpictures, in the form of motion blur,reduced depth-of-field, and visiblenoise. In some cases, we may havesome control over the intensity ofillumination, as when shootingindoors with artificial light fixtureswe can adjust or dim. Outdoors, itsbeyond our abilities to adjust thebrightness of the sun, but we canintroduce translucent or opaquelight-blockers to the path of the lightto intercept some of it, or reflectorsto re-direct the illumination.

Figure 1.14The threeelements of this triangledetermine theexposure ofyour image.


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Light duration. Light sourcesarent necessarily continuous.Electronic flash units, for example,expend all their light within a briefperiod, quickly enough to affect theoverall exposure when flash is themain illumination of an image.Indeed, if flash is the primary light source, the effective shutterspeed of the exposure is the duration of the flashs burst.Although the camera may havebeen set to 1/250th second, theaction-stopping capabilities of theflash might be 1/1,000th second.

Light emission, reflection, ortransmission. Light reaches thelens directly (as when light from acandle is captured in an image);by reflection (bouncing off anobject); or by transmission (afterpassing through a translucentobject thats lit from behind). Theamount of light that completes thisjourney without being absorbed,blocked, spread (diffused), or inter-rupted determines the exposurerequired.

Light passing through thelens. Not all of the illuminationthat reaches the lens passesthrough to the sensor. If you have afilter mounted on your lens, it willremove or modify some of the light(see Figure 1.15). Inside the lens, avariable-sized roughly circulardiaphragm, or aperture, dilatesand contracts to control the amountof light that enters the lens. The

aperture is adjusted in size by yourcameras autoexposure system, orby manual settings you make. Asyoull learn in the next section, therelative size of the aperture iscalled the f/stop.

Light passing through theshutter. Once light makes it allthe way through the lens, theamount of time the sensor isexposed to that illumination isdetermined by the cameras shutter.

The shutter can remain open for aslong as 30 seconds (or even longerif you use the Bulb setting) or asbriefly as 1/8,000th second,depending on which digital cam-era you own. The shutter may bea physical device that opens andcloses for a given period of time,or, in the case of the highest shutterspeeds, an electronic mode thatactivates and deactivates the sen-sor for a brief period while thephysical shutter is open.

Light captured by the sensor.Finally, the illumination that a frac-tion of a second ago began itsjourney from your subject to thecamera crosses the finish line andreaches the sensor. But not all thelight passing through the shutter iscaptured by the individual pixels(or photosites) of the sensor. If thenumber of photons reaching a par-ticular photosite doesnt pass a setthreshold, no information isrecorded. Similarly, if too muchlight illuminates a pixel in the sen-sor, then the excess isnt recordedor, worse, spills over to contami-nate adjacent pixels. We can mod-ify the minimum and maximumnumber of pixels that contribute toimage detail by adjusting the ISO(or sensitivity) setting. At higherISOs, the incoming light is ampli-fied to boost the effective sensitivityof the sensor.

These aspectsthe quantity oflight produced by the lightsource, the amount reflected ortransmitted towards the camera,the light passed by the lens, theamount of time the shutter isopen, and the sensitivity of thesensorall contribute to theactual exposure.

Figure 1.15 A filter placed in front of the lens removes some of thelight before it reaches the sensor.


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F/StopsMany people rely most on onlytwo legs of the exposure triangle:they set their ISO sensitivity to avalue appropriate for the type ofphotos they are going to take (alow ISO outdoors in bright sun-light; a higher setting for sports,indoors, or in other reduced-lightenvironments) and forget it. (Theyalso may forget that many cam-eras have an auto ISO optionthat adjusts sensitivity for them,sometimes producing unintendedresults.)

Then, they (or their camerasexposure meter) adjust only thef/stop, shutter speed, or both, toarrive at an exposure. Thats acommon practice, and theresnothing wrong with it as long asyou keep in mind that ISO sensi-tivity is an available and impor-tant option for adjustingexposure.

I like to use the term f/stop fre-quently when referring to the lensopening, in order to remind youthat the expression represents afraction, as Ill explain shortly.

However, an f/stop can also beproperly referred to as an aper-ture, and the physical lens featureis often called the iris diaphragmor simply diaphragm. These areall terms that describe a variable-sized, roughly circular opening inthe lens that dilates and shrinks todetermine the amount of light thatpasses through the lens to thesensor.

This aperture is roughly compara-ble to the pupil of the human eye.When the light is bright andharsh, the pupils contract; underdimmer conditions, the pupilsexpand to admit more light.F/stops arent absolute values: anaperture described as f/8 withone lens may actually be larger

or smaller than an f/8 settingwith a different lens. Thatsbecause they represent the rela-tive size of the actual physicallens opening compared to thefocal length of the lens. For exam-ple, with a lens with a focallength of 50mm, an aperture thatmeasured 12.5mm in diameterwould produce a lens openingwith the value f/4 (50 divided by12.5). The same size opening ina lens with a 100mm focal lengthwould produce a lens openingwith the value f/8 (100 dividedby 12.5).

Because of this relationship, youcan visualize f/stops as thedenominators of fractions. Thatswhy larger f-numbers represent

Figure 1.16An aperture off/5.6 (left) islarger than anaperture of f/8(right).

F/STOPS VERSUS STOPSIn photography parlance, f/stop always means the aperture or lens open-ing. However, for lack of a current commonly used word for one exposureincrement, the term stop is often used. (In the past, EV served this purpose,but Exposure Value and its abbreviation has been inextricably intertwinedwith its use in describing Exposure Compensation.) In this book, when Isay stop by itself (no f/), I mean one whole unit of exposure, and am notnecessarily referring to an actual f/stop or lens aperture. So, adjusting theexposure by one stop can mean both changing to the next shutter speedincrement (say, from 1/125th second to 1/250th second) or the nextaperture (such as f/4 to f/5.6). Similarly, 1/3 stop or 1/2 stop incrementscan mean either shutter speed or aperture changes, depending on the con-text. Be forewarned.


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smaller apertures, and smallerf-numbers represent larger aper-tures (see Figure 1.16). Once youbecome smarter than a fifthgrader (long ago, or recently),you have no trouble with the con-cept that 1/2 is larger than 1/4and 1/8, and that 1/16 issmaller than even an odd-ballfraction like 1/11. Similarly, f/2is larger than f/4 and f/8, andf/16 is smaller than f/11.

Of course, it doesnt help demys-tify things to know that the rela-tionship between f/stops involvesthe square root of two (1.4). So,f/2 isnt twice as large as f/4 interms of area; its four times aslarge, just as f/4 is actually fourtimes as large as f/8.Intermediate numbers, based onthat pesky square root of two, areneeded to represent actual dou-bling and halving of aperturesize. So, a lens might be marked:

f/2, f/2.8, f/4, f/5.6, f/8, f/11,f/16, f/22

with each larger number repre-senting an aperture that admitshalf as much light as the onebefore. You need to understandthat relationship to calculate

exposure, or to apply exposuresettings selected by your cam-eras metering system.

While were most concernedabout lighting and exposure inthis book, you should be awarethat your choice of an f/stop hasother effects on your image thatcan cascade down to your light-ing and exposure decisions.

These include:

Overall sharpness. The f/stopyou select can have a dramaticeffect on the sharpness of yourimage. Most lenses are not at theirsharpest wide open using thelargest f/stop. They will performbetter at an opening thats one ortwo stops smaller (say, f/8 with alens having a maximum aperture off/4). Nor do most lenses producetheir best results at the smallest lensopenings, due to a phenomenon

called diffraction. Light striking theedges of the diaphragm at, say,f/22, scatter, reducing sharpnesscompared to a larger f/stop, suchas f/8. If your lighting scheme isdesigned to enhance the textureand sharpness of your subject,youll want to choose an f/stopthat doesnt detract from that goal.

Depth-of-field. The f/stopselected also determines the rangeof sharpness available, calleddepth-of-field. Larger apertures(smaller numbers) produce lessDOF (see Figure 1.17), whilesmaller apertures (larger numbers)generate more DOF. You may planyour lighting for a portrait so thatthe background is de-emphasized.If so, you might want to use theavailable depth-of-field as an addi-tional tool.

Background appearance. Thef/stop used can affect how the out-of-focus portions of your imageappear, a process thats separatefrom depth-of-field considerations.This property is called bokeh, froma Japanese word meaning blur,and determines whether out-of-focus highlights in the imageappear as visible discs, or as lessobtrusive shapes that are lessprominent. While bokeh is impor-tant from a pictorial standpoint, interms of lighting it is significantchiefly in how the backgroundscomplement or detract from yourlighting arrangement.

Figure 1.17 Larger apertures produce a very narrow range of sharpness, ordepth-of-field.


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Shutter SpeedsThe second leg of the exposuretriangle that most of us work withis the shutter speed, representedin fractions (of a second), such as1/60th, 1/125th, 1/250th,1/500th, and 1/1,000th second(at least, until the fraction reaches1/1 and the measurements con-vert to whole seconds). In prac-tice, the numerator is usuallyomitted, so that 60, 125, 250,500, 1,000, and so forth areused instead. Most digital cam-eras represent exposures oflonger than a second with num-bers followed by a single or dou-ble quote mark, so 2", 2.5", and4", and so forth represent 2.0,2.5, and 4.0-second exposures,respectively.

As I noted earlier, exposure set-tings are most commonly madeusing the aperture and shutterspeed, followed by adjusting theISO sensitivity if its not possible

to get the preferred exposure(that is, the one that uses thebest f/stop or shutter speed for the depth-of-field or action-stopping we want).

In modern cameras, the shutterresides just in front of the sensor,which lies in the focal planewhere light focused by the lensconverges. Such shutters are,appropriately, called focal planeshutters. The most common typeof focal plane shutter consists of apair of curtains that travel verti-cally. The gap between the cur-tains allows the sensor to beexposed to light. A shutter that isclosed prior to exposure lookssomething like Figure 1.18. (Theillustration is not a photograph ofan actual focal plane shutter; itsjust a concoction I put together toshow you how all the elements ofa shutter work together.)

Focal Planes andShutter SpeedsWhen the shutter button isdepressed all the way, the firstcurtain moves up, exposing thesensor, as you can see in Figure1.19. After a period of time, thesecond curtain begins to travelupwards, too, trailing the first cur-tain and producing a moving

slit as shown in Figure 1.20.The width of the slit determinesthe relative shutter speed. A nar-row opening produces a fast shut-ter speed; a wider openingcreates a slower shutter speed.

There are a couple limitationsyou should know about. Figures1.19 and 1.20 show a slit widththat, in this fictitious camera,

Figure 1.18 The focal plane shutter is completely closed.


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produces a shutter speed of1/500th second. A slit twice aswide would create a shutterspeed of 1/250th second, andone twice as wide as that wouldresult in a shutter speed of1/125th second. Indeed, that 4Xwidth exposes the whole sensorat once, and cant get any wider,so shutter speeds longer than1/125th second are producedby introducing a delay before thesecond curtain starts to close.Exposing the sensor to light for

30 seconds before the secondcurtain begins its upward travelwould give you a shutter speed of30 seconds (natch).

Going in the other direction,theres a limitation on just hownarrow the slit can be. With ourfictitious example camera, the slitwould need to be 1/2 as wide tocreate a 1/1,000th second shut-ter speed, 1/4 as wide for1/2,000th second, and 1/8 aswide for 1/4,000th second.

Many digital cameras cant nar-row the gap between the first andsecond curtains any more thanthat, so 1/4,000th second is thetop shutter speed. A few can goto 1/8,000th second or faster.Some cameras generate fastershutter speeds electronically, byturning the sensor on or off veryquickly while the two shutter cur-tains are wide open.

But wait, as they say, theresmore! Electronic flash has a very

brief duration, much shorter thanthe shutter curtains vertical travelat fast speeds. Camera designerswork around this problem byallowing the flash to fire only dur-ing that period when the shutteris completely open. With ourexample camera, the shutter isfully open at 1/125th second;flash pictures can be taken atshutter speeds of 1/125th sec-ond or slower.

Figure 1.19 The first curtain has traveled 1/4 of the distance across the focalplane, exposing the sensor through the slit produced.

Figure 1.20 The first curtain continues to travel, and the second curtain beginsto trail it, gradually exposing the sensor.


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Because shutter speeds andf/stops are proportional, you canproduce the exact same exposureusing many different combina-tions of settings. Table 1.1 showsequivalent exposure settingsusing various shutter speeds andf/stops. Ill explain more aboutcalculating the best exposure inthe next chapter.

If your camera has chosen one ofthese exposure pairs, and youdrather use a different combina-tion, there will usually be a provi-sion to change from oneexposure pair to an equivalent

pair by spinning a dial or adjust-ing some other control. So, ifyour camera has chosen1/500th second at f/4 andyoud prefer a little more depth-of-field, you can use the control toswitch to 1/250th second atf/5.6 or 1/125th second at f/8using the same ISO setting.Conversely, if youd rather workwith a wider f/stop to apply lessdepth-of-field for selective focus,you can switch to 1/1,000th second at f/2.8, or 1/2,000thsecond at f/2 (assuming yourlens has either or both of thosefairly large aperture options).

You can switch among equivalentexposures in Aperture Priority orShutter Priority modes, too, butonly by changing the dominantcontrol in your selected mode.That is, to produce a faster orslower shutter speed in AperturePriority mode while retaining thesame exposure, you must adjustthe aperture up or down. To usea larger or smaller aperture inShutter Priority mode, switch to afaster or slower shutter speed.

As with f/stops, the shutter speedyou select has effects on yourimage other than exposure:

Subject blur/sharpness. Fastershutter speeds are required tofreeze fast-moving objects, thosein motion that are closer to thecamera, and those that are movingacross the frame. In each case, themotion is more apparent becauseof the speed, distance, or directionof the subject. Conversely, youllfind that slower shutter speeds willwork well for objects that are sta-tionary or not moving quickly,those that are more distant, orwhich are moving toward the cam-era, because the apparent motion

is less. Using motion-stoppingcapabilities, or allowing movementto blur is your choice, and part ofyour creative decision. Some typesof pictures, just as motor racing,look best when there is at leastsome blur to indicate that the sub-ject was moving.

Camera/lensmovement/sharpness. A sec-ond kind of motion blur, caused bymovement of the camera or pho-tographer, can also affect pictures.In some cases, it can be appliedcreatively, as when the camera ispanned from side to side to cap-ture a sharp image of an athletewhile allowing the background toblur, as you can see in Figure1.21. But, most of the time, camerashake just robs your pictures ofsharpness. It can be produced dur-ing long exposures if the cameraisnt mounted on a tripod or othersupport (or, even when properlymounted if the support is less thanrock steady). Camera shake isincreased by long lenses, whichmagnify the motion of the cameraat the same time distant subjectsare brought closer. If cameramotion blur is objectionable, use asturdy support; select a faster shut-ter speed; or use a camera or lens

Table 1.1 Equivalent Exposures

Shutter speed f/stop Shutter speed f/stop

1/8th second f/32 1/250th second f/5.6

1/15th second f/22 1/500th second f/4

1/30th second f/16 1/1,000th second f/2.8

1/60th second f/11 1/2,000th second f/2

1/125th second f/8 1/4,000th second f/1.4


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with built-in vibration reduction/image stabilization/anti-shake fea-tures. Nikon and Canon build thisfeature into many of their lenses;Sony, Olympus, Pentax, and othersinclude it in the camera body sothat every lens can be used withthe stabilization feature.

Figure 1.21 Camera motion can be used creatively to introduce blur to an action picture.

Noise. Longer shutter speeds (usu-ally those of several seconds andlonger) can introduce those ran-dom, multicolored speckles we callvisual noise into your photographs.(Another, equally objectionabletype of noise is produced at thehighest ISO settings of a camera.)

While the built-in noise reductionfeatures of digital cameras canmask this visual interference, theytend to rob your image of detail,too. So, you should consider thepossibility of noise when selectinglonger shutter speeds (and higherISOs).

Use of flash. As I noted earlier,the shutter speed you select canaffect your use of electronic flashfor a given photograph. Most digi-tal cameras have a maximum shut-ter speed (usually between1/160th and 1/500th second) atwhich flash can be used. (Somehave a mode called high speedsync that allows flash at evenfaster speeds, but reduces theeffective output of the flash.) Whenit comes to use of lighting, thismaximum sync speed can crampyour style when you want to useflash as a fill-in under high light lev-els. If the overall exposure in day-light that you want to use is1/1,000th second at f/8 (say, forreduced depth-of-field when usingselective focus), your flash isntgoing to do you much good to fillin the shadows if your cameraallows a shutter speed no fasterthan 1/200th second. Shutterspeed can also be a limitation atthe low end, too; if you use flashwith a low shutter speed (to pre-vent the surroundings from goingpitch-black), you can end up withghostly secondary images unlessthe camera is mounted on a tripod.


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Adjusting Exposure with ISO SettingsThe third way of adjusting expo-sure is by changing the ISO sensi-tivity setting. This option is oftenoverlooked, or used as a lastresort. Thats because higherISO settings are seen as neces-sary evils. Youre told you shoulduse the lowest ISO setting possi-ble for best quality, and increasethe sensitivity only if a given ISOdoesnt allow the best expo-sure. So, we tend to set the ISOonce for a particular shootingsession (say, at ISO 100 or 200for bright sunlight outdoors, orISO 800 when shooting indoors)and then forget about it.However, changing the ISO is avalid way of adjusting exposuresettings, especially if you own anewer digital camera, as the lat-est batch tend to minimize visualnoise at reasonable ISO settings,with many fully usable up to ISO800 or ISO 1,600 (and beyond)with very little objectionablevisual noise.

The typical digital camera hasISO options ranging from ISO100 (although some go as low asISO 50) up to around ISO 1,600or ISO 3,200. A few newer cam-eras offer ISO settings of 6,400(while still producing acceptableresults), and one of my favoritemodels actually has High 1 andHigh 2 settings that are the equiv-alent of ISO 12,800 and ISO25,600. At the latter setting, thepictures are usually too grainy touse, but Ive actually gottendecent results. Figure 1.22 showsan informal snapshot grabbed ata camera club meeting where Iwas complaining that ISO25,600 was overkill, and tookthis photo of the club president at1/250th second at F/11(indoors!) using that lofty ISO set-ting with a Nikon D3. I wasunable to make my point,because the image, as you cansee, doesnt look that bad, grainand noise-wise.

Although I steer away from ISOsettings higher than 3,200 withmost cameras, I do end up usingISO adjustments quite frequentlywhen shooting in the studio.Thats especially true in Manualmode, which is my only optionwhen using studio flash (whichare not compatible with my cam-eras TTL electronic flash exposuresystem). My studio flash units pro-duce bursts that call for exposuresat f/11 or f/16 at ISO 200. If Iwant a little more exposure, I canswitch to ISO 400, or, for a littleless, change to ISO 100, with noneed to change the f/stop (whichincreases or decreases yourdepth-of-field). Or, I can changeto a larger or smaller f/stop, andadjust the ISO to keep the sameexposure.

Outside the studio and sans flash,perhaps, I am using ShutterPriority mode (discussed in thenext chapter) and the metered

exposure at ISO 200 is 1/500thsecond at f/11. If I decide on thespur of the moment Id rather use1/500th second at f/8, I canpress a button to switch to ISO100. Its a good idea to monitoryour ISO changes, so you dontend up at ISO 1,600 acciden-tally. Many cameras can adjustthe ISO automatically as appro-priate for various lighting condi-tions.

If you must use a high ISO settingto adjust exposure, take advan-tage of your cameras noisereduction (NR) features. Somemodels have a single NR option,which can be turned on or dis-abled entirely if you want toavoid the loss of detail thataggressive noise reduction canproduce. Others allow choosinga level of noise reduction, fromlow, medium, to high, plus off.Noise cancellation can be broken


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down into two categories as well:High ISO Noise Reduction andLong Exposure Noise Reduction,because each type of situationproduces a different type ofnoise. You can activate or deacti-vate the High ISO and LongExposure noise reduction sepa-rately, as you might not needboth.

The visual noise produced byyour camera can also be mini-mized or eliminated using pro-grams that run on your computer,after the shot has been taken andtransferred to your hard disk.Adobes Camera Raw plug-in forPhotoshop and PhotoshopElements has built-in noise reduc-tion that can be applied when theimage is imported. Both imageeditors have their own noise can-cellation filters, as well. Noisereduction is included with third-party applications like NoiseNinja and Bibble Pro. Onceyouve learned how to minimizethe effects of noise at high ISOsettings, youll have the freedomto use sensitivity adjustments asan exposure tool more often.

Figure 1.22High ISO settingsdont necessarily leadto disaster with newerdigital SLRs, as thisISO 25,600 snapshotproves.

T he light you work with comes in many forms. You may usethe light thats available at a scene, supply your own illumi-nation, or manipulate light to provide the exact look youwant. But, no matter how carefully you shape your picture with light,if the exposure is wrong for that image, you may not get the effectyou seek. A carefully crafted silhouette exposed improperly may betransformed into a murky portrait with a washed-out background. Ifthe exposure is incorrect, your languid landscape might emphasizean uninteresting foreground at the expense of a gorgeous expanse oflush foliage in the middle part of an image, because our eyes areautomatically attracted to the brightest parts of an image. Exposure,composition, and lighting must work hand-in-hand to produce the bestphotos.

Digital SLRs use light-sensitive electronicsthe cameras built-inmeterto measure the light passing through the lens. Digital SLRs usemuch more refined methods of metering light, too, compared to the

earliest through-the-lens film models that measured an amorphous blobof light averaged out over the entire frame, without much regard towhere specific bits of illumination originated in the image.

There are three different aspects of calculating exposure that youneed to take into account when working with a digital camera. Howand where within a scene is the exposure measured? Thats the cam-eras metering mode. Once the amount of illumination is measured,what controls, such as shutter speed, f/stop, and ISO sensitivity, areused to adjust the camera to arrive at the correct exposure? Thoseoptions are usually called the exposure modes. Finally, how can youadjust exposure to override or fine-tune the settings calculated by thecameras metering system? The tools you have to work with includeexposure value (EV) compensation, and bracketing. This chapterexplains all the elements that go into arriving at the right exposure fora particular image.

Optimizing Exposure2


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Metering ModesThis section introduces you to thethree to five different meteringmodes found in advanced digitalcameras, especially digital SLRmodels. Each of them divides thearea seen in the viewfinder intoexposure zones, and gives moreor less emphasis to some of thezones, depending on the modeyouve selected and the program-ming of the camera.

Evaluative/MatrixThe best choice for most situa-tions is Matrix metering, alsocalled Evaluative metering.Brightness patterns from a largenumber of metering zones in theframe (from 35 to more than1,000) are collected, and thencompared against a large data-base of sample pictures compiledby the camera manufacturer.Matrix metering enables the cam-era to make some educatedguesses about the type of pictureyou are taking, and chooses anexposure appropriately. Forexample, if the camera detectsthat the upper half of the frame is

brighter than the bottom half, itmay make a reasonable assump-tion that the image is a land-scape photo and calculateexposure accordingly. Your cam-era is not only capable of figur-ing out that youre shooting alandscape photo, it can probablyidentify portraits, moon shots,snow scenes, and dozens ofother situations with a highdegree of accuracy.

In addition to overall brightness ofthe scene, the system may makechanges based on the focus dis-tance (if focus is set on infinity, theimage is more likely to be a land-scape photo); focus or meteringarea (if youve chosen a particu-lar part of the frame for focus ormetering, thats probably the cen-ter of interest and should be givenadditional weight from an expo-sure standpoint); and the differ-ence in light values throughout theframe (effectively, the contrastrange of the image).

The camera may even be able todecide when its best to provide

less exposure than might becalled for when using a dumbexposure system. Its often smartto build in some bias towardsunderexposure, because incor-rectly exposed shadows are eas-ier to retrieve later on (say, inyour image editor) than overex-posed (blown highlights).

PartialWhen you want to emphasize alarge central area of an imagewhen calculating exposure, youmight want to use the modecalled Partial, which is a fauxSpot mode offered by Canon inits digital SLRs. It uses roughlynine percent of the image area tocalculate exposure, which is arather large spot. Introducedwith early models of CanonsdSLR line, Partial metering hasbeen mostly supplanted by trueSpot metering and Center-Weighted metering. Use thismode if the background is muchbrighter or darker than a largishsubject in the center of the frame.

SpotIf you want to ignore the bright-ness in most of an image andzero in on a specific subject, youcan use Spot metering. This modeconfines the reading to a limitedarea in the center of theviewfinder, which may make upjust two to about four percent ofthe total image, depending onyour camera. This mode is usefulwhen you want to base exposureon a small area in the frame.

The calculations arrived at withSpot metering can vary depend-ing on the size of the spot, whatthe camera elects to do with thespot of information, and howmuch flexibility the photographeris given over the process. Withsome cameras, you might beable to choose the size of thespot. Or, you may be allowed tomove the spot around in theviewfinder using your camerascursor controls (usually switchingfrom one autofocus zone toanother), so that you meter thesubject area of your choice,

Optimizing Exposure

23

rather than a central area forcedon you by the camera.

If your camera doesnt have theoption of moving the meteringspot, you can frame the image sothe area you want to measure isin the center of the frame, andthen lock exposure (usually bypressing the shutter releasehalfway, or by holding down adedicated exposure lockAE-Lbutton). Youll find this Spot meter-ing especially useful for backlitsubjects or macro photography.

Center-WeightedA Center-Weighted meteringmode allows emphasizing a sub-ject in the middle of the framewhile also taking into account therest of the image. In this mode,the exposure meter emphasizes azone in the center on the theorythat, for most pictures, the mainsubject will be located in the cen-ter. Center-Weighting works bestfor portraits, architectural photos,and other pictures in which themost important subject is locatedin the middle of the frame. As thename suggests, the light readingis weighted towards the centralportion, but information is also

used from the rest of the frame. Ifyour main subject is surroundedby very bright or very darkareas, the exposure might not beexactly right. However, thisscheme works well in many situa-tions if you dont want to use oneof the other modes.

One vendors camera may calcu-late Center-Weighted exposurebased on an average of all thelight falling on a frame, but withextra weight given to the center(the size of which may beadjustable). Others may use amodified spot system with a reallylarge, fuzzy spot, so that light atthe periphery of the frame is virtu-ally ignored, even though the sys-tem is called Center-Weighting.

AveragingVery few cameras offer anAveraging mode, which givesequal weight to all portions of animage. Averaging is the leasteffective metering method in mostcircumstances, because it doesntallow for differences in brightnessbetween important and unimpor-tant parts of your picture. If yourcamera offers an averagingoption, it would be useful if you

happen to have a neutral graycard (described in more detaillater in this chapter). If you fill upthe frame as seen through theviewfinder with the gray carditself, an Averaging meter wouldsuggest an accurate exposure forthat gray card. You could thentake a picture of a scene illumi-nated by the same kind of lightand be confident that the middletones of the scene, including themedium gray of the card itself,would be rendered properly. But,most of the time, youll want touse one of the other meteringoptions to calculate exposure.

Figure 2.1 shows the approxi-mate coverage areas of four

metering modes offered withCanon digital SLRs, with theviewfinder/LCD icon used to indi-cate them shown in the upper-leftcorner of each representation.Nikon, Pentax, Sony, Olympus,and other vendors have a similarmix of metering modes, and usetheir own icons. At upper left youcan see the 35 different exposurezones used for Evaluative(Matrix) metering; at upper right,the large circle that represents thefaux Spot mode called Partial; atlower left, the area metered inSpot mode is indicated in blue;while at lower right you can seethe middle zone of the frame thatis emphasized in Center-Weighted mode.

Figure 2.1TypicalEvaluative/Matrix (upperleft); Partial(upper right);Spot (lower left),and Center-Weighted (lowerright) meteringmode coverage.


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Aperture PriorityOnce the amount of light hasbeen measured and the correctexposure calculated, digital cam-eras need to apply that informa-tion by setting the shutter speed,aperture (lens opening), or ISO(sensitivity of the sensor). Mostdigital cameras have up to fivedifferent types of exposure modesthat determine how the exposuresettings are made. These includeAperture Priority, Shutter Priority,Program, Manual, and, withsome cameras, a set of customexposure modes usually calledScene modes.

In Aperture Priority mode, youselect the f/stop you want to use,and the camera selects the appro-priate shutter speed needed forthe correct exposure. (Some cam-eras can be set to adjust the ISOif the selected aperture requires ashutter speed that is faster orslower than the ideal setting.)

Aperture Priority is also calledAperture Preferred, and is abbre-viated either A or Av (for aper-ture value) on your cameracontrols.

Aperture Priority is an excellentchoice when you want to use aparticular lens opening toachieve a desired effect. Perhapsyoud like to use the smallestf/stop possible to maximizedepth-of-field in a close-up pic-ture. Or, you might want to use alarge f/stop to throw everythingexcept your main subject out offocus, as shown in Figure 2.2.Perhaps youd just like to lockin a particular f/stop becauseits the sharpest available aper-ture with that lens. Or, you mightprefer to use, say, f/4 on a lenswith a maximum aperture off/2.8, because you want the bestcompromise between speed andsharpness, as in Figure 2.3

Figure 2.2Aperture pri-ority allowsspecifying alarge aper-ture for selec-tive focus thatconcentratesattention onthe main subject.

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Aperture Priority can even beused to specify a range of shutterspeeds you want to use undervarying lighting conditions, whichseems almost contradictory. Ifyoure shooting a soccer gameoutdoors with a telephoto lensand want a relatively high shutterspeed, but you dont care if theshutter speed changes a littleshould the sun duck behind acloud, set your camera toAperture Priority, and adjust theaperture until a shutter speed of,say, 1/1,000th second isselected at your current ISO set-ting. (In bright sunlight at ISO400, that aperture is likely to bearound f/11.) Then, go aheadand shoot, knowing that yourcamera will maintain that f/11aperture (for sufficient DOF as thesoccer players move about thefield), but will drop down to1/750th or 1/500th second ifnecessary should the lightingchange a little.

Keep in mind that the cameramay be unable to select anappropriate shutter speed at thepreferred aperture and that over-and underexposure will occur atthe current ISO setting. Thats themajor pitfall of using AperturePriority: you might select anf/stop that is too small or toolarge to allow an optimal expo-sure with the available shutterspeeds. For example, if youchoose f/2.8 as your apertureand the illumination is quitebright (say, at the beach or insnow), even your cameras fastestshutter speed might not be ableto cut down the amount of lightreaching the sensor to providethe right exposure. Or, if youselect f/8 in a dimly lit room, youmight find yourself shooting witha very slow shutter speed thatcan cause blurring from subjectmovement or camera shake.Aperture Priority is best used bythose with a bit of experience inchoosing settings. Many sea-soned photographers leave theircameras set on Aperture Priorityall the time.

Figure 2.3 In this case, an aperture of f/4 was selected to provide the bestcompromise of speed, sharpness, and depth-of-field when capturing this wary owl.


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Shutter PriorityShutter Priority is the opposite ofAperture Priority. In this mode,you select the shutter speed youdlike to work with, and the cam-eras metering system selects theappropriate f/stop. Perhapsyoure shooting action photosand you want to use the absolutefastest shutter speed availablewith your camera; in other cases,you might want to use a slowshutter speed to add some blur to

a sports photo that would bemundane if the action were com-pletely frozen. Shutter Prioritymode gives you some controlover how much action-freezingcapability your digital camerabrings to bear in a particular situ-ation. Shutter Priority is alsocalled Shutter Preferred, and maybe abbreviated on your camerascontrols as S or Tv (for timevalue).

Of course, Shutter Priority pres-ents the same problem you mightencounter with Aperture Priority.Its possible to select a shutterspeed thats too long or too shortfor an ideal exposure under someconditions. Ive shot outdoor soc-cer games on sunny Fall eveningsand used Shutter Priority mode tolock in a 1/1,000th second shut-ter speed, only to find my camerarefused to shoot when the sundipped behind some trees andthere was no longer enough lightto shoot at that speed, even withthe lens wide open. Your camerawill tip you off with a blinking Hior Lo or other message in theviewfinder, so you can select adifferent shutter speed and tryagain.

As with Aperture Priority, you canuse Shutter Priority to lock in aspecific range of apertures thatwill be used. To use our soccer

game example again, perhapsyou want to make sure you use arelatively small f/stop, such asf/11, but you dont care if theaperture changes a little. A highshutter speed is your main prior-ity. Go ahead and set your cam-era to Shutter Priority, and adjustthe shutter speed until an aper-ture of f/11 is selected at yourcurrent ISO setting. (In bright sun-light at ISO 400, that shutterspeed will be around 1/500thsecond.) Shoot away. If lightingconditions remain the same, yourcamera will maintain that f/11aperture, but will drop down tof/8 or an intermediate f/stop ifnecessary should the lightingchange a little during the game.

The shutter speed you select for agiven photo affects two key partsof your image: the overall expo-sure (when mated with the ISOand f/stop parameters) and the

AUTO ISOWith both Shutter Priority and Aperture Priority, you may have the optionof directing your camera to increase or decrease the ISO sensitivity tokeep those shutter speeds and apertures within the ideal range.Cameras that implement this feature may let you specify a minimum shutterspeed and maximum ISO setting to use in this ISO Auto mode. For exam-ple, in Aperture Priority mode, if you want to avoid using shutter speedslower than 1/30th second, you can tell the camera to raise the ISO when-ever a shutter speed slower than that is specified by the exposure system.In either Aperture or Shutter Priority modes, you can specify that ISO willbe increased, say, to no more than ISO 1000 automatically, avoidinghigher sensitivity settings that can increase grain.

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relative sharpness of your imagein terms of how well subject orcamera motion is stopped. Ahigh shutter speed will freeze fast-moving action in front of yourcamera, and potentially negateany shakiness caused by cameramovement. If a shutter speed is

not high enough to stop thismovement, elements in yourimage will be stretched andblurred. Creatively, you mightactually want this blur in order toadd a feeling of motion to yourimages. So, its important tochoose the right shutter speed to

stop action when you want tofreeze a moment in time, or toallow your subject to flow whenthats what youre looking for.

To maintain the most control over the amount/lack of blur inyour photographs, you need to

understand that components inyour image are subject to thisblurring to varying degrees.Indeed, its possible to have oneimage with several subjects, eachwith a different amount of blur.Here are some things to keep inmind when selecting a shutterspeed:

High shutter speeds countercamera shake. If your camerashakes during an exposure, all ofthe image will be blurry to adegree. Anti-shake measures builtinto the camera or image stabiliza-tion/vibration reduction included ina lens can counter some camerashake, but are not cure-alls. Highershutter speeds (1/500th to1/1,000th second or shorter) canhelp eliminate camera shake.

Motion across the framerequires higher shutterspeeds. Motion across the frame(left to right or right to left) appearsto move more quickly than motionthats headed toward or away fromthe camera. In Figure 2.4, thebaseball is traveling across theframe, and so appears slightlyblurred even at a shutter speed of1/500th second. A speed of1/2,000th second would freezethe ball in mid-flight, but the blurshown here is actually more effec-tive because of the feeling ofmotion it adds to the image.

Figure 2.4 Action across a frame requires the highest shutter speed to freeze action.


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Motion towards the cameraseems slowest. Motion comingtoward the camera appears tomove much more slowly. An athletebarreling over high hurdles (as inFigure 2.5) can be frozen at a rela-tively slow shutter speed1/250thsecond may be sufficientbecausethe apparent motion isnt as fast.

Slanted movement is inbetween. If a subject starts outon one side of your frame, andapproaches you while headed tothe other side, it will display blursomewhere between the twoextremes.

Distance reduces apparentspeed. Subjects that are closer tothe camera blur more easily thansubjects that are farther away,even though theyre moving at thesame absolute speed, becausetheir motion across the cameraframe is more rapid. A vehicle inthe foreground might pass in frontof the camera in a split-second,while one hundreds of feet awaymay require three or four secondsto cross the frame.

A moving camera empha-sizes or compensates forsubject motion. If you happen tobe moving the camera in the samedirection as a subjects motion (thisis called panning), the relativespeed of the subject will be less,and so will the blur. Should youmove the camera in the other direc-tion, the subjects motion on theframe will be relatively greater.

The correct shutter speed willvary based on these factors, com-bined with the actual velocity ofyour subject. (That is, a tight endracing for a touchdown in an NFLgame is very likely moving faster[and would require a faster shut-ter speed] than, say, a 45-year-old ex-jock with the same goal ina flag football game.) The actualspeed you choose also varieswith the amount of intentionalblur you want to impart to yourimage, as in Figure 2.6.

Figure 2.5 Action moving toward the camera, such as this shot of a hurdler at1/250th second, can be captured at a slightly slower shutter speed.

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For example, if you want toabsolutely stop your subject in itstracks, you might need1/1,000th to 1/2,000th second

(or faster) for the speediesthumans or speeding automobiles.You might apply 1/500th secondto a galloping horse to allow a

little blur in the steeds feet ormane. Shutter speeds as slow as1/125th second can stop somekinds of action, particularly if you

catch the movement at its peak,say, when a leaping basketballplayer reaches the top of his orher jump and unleashes the ball.

Figure 2.6 Panning the camera while shooting at a slow shutter speed can produce an interesting sports photo.


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Programmed Exposure ModesVirtually all digital cameras havea user-adjustable fully automaticexposure mode called Program,Programmed Exposure, orProgrammed Auto, usuallymarked with a P on the cameracontrols. Entry-level and someintermediate models may haveadditional programmed exposuremodes, including Auto or FullAuto, and a series of settingscalled Scene modes suitable forspecific types of situations (andwith names to match), such asPortrait, Landscape, Sports,Night, or Close-Up. Scene modesmay be categorized by differentnames by various manufacturers.(Canon calls them Basic Zonemodes, while Nikon prefers theterm Digi-Vari Program.) The con-cept is the same: with any pro-grammed mode, the cameramakes most (or all) of the deci-sions for you, and may or may

not permit overriding those set-tings. Fortunately, these automaticmodes usually work with yourcameras Matrix metering method(described earlier in this chapter),so they can intelligently analyzeyour image and arrive at a fairlyaccurate exposure on their own.

Dont confuse P mode (discussednext) with Auto or Full Auto,which is usually marked on thecamera with a green cameraicon, the words AUTO, or agreen rectangle (because A or Avusually means Aperture Priority).Fully automatic exposure

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Quick snap guide to lighting