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EXPOSURE For Outdoor Photography MICHAEL FRYE

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  • EXPOSURE For Outdoor Photography MICHAEL FRYE

  • In photography, creativity and technical

    skill are both essential. A wonderful eye and

    imagination might help you find fantastic

    compositions that nobody else would see,

    but if the images are three stops overexposed,

    and unintentionally blurred, no one will be

    able to appreciate your geniustheyll just

    see washed-out, fuzzy photographs. Good

    technique can amplify a photographs mes-

    sage, and bad technique can detract from it.

    The most essential technical skill a photogra-

    pher must master is exposure. On the surface,

    exposure seems easy. Its simply a matter of

    making the image bright enoughnot too

    dark, and not too light. But the endless variety

    of light makes exposure challenging. No two

    situations are the same, so there can be no

    exact formula for getting the right exposure.

    On the other hand, exposure doesnt need

    to be overly complicated. The fundamental

    controlsshutter speed, aperture, ISO, light

    metersare easy to understand. And digital

    cameras have eliminated a lot of the guesswork.

    We can use the cameras LCD screen, andeven

    betterthe histogram to evaluate the exposure.

    Well start with these fundamentals, and then Ill

    show you ten practical, real-life examples where

    Ive used these principles to control the exposure,

    the sharpness, and the photographs message.

    Introduction

    WHY DOES EXPOSURE MATTER?

    Understanding the fundamentals can help you quickly find the

    right exposure to capture a fleeting moment like this.

    2

  • The exposure for any given image is determined by four things: the light, shutter speed, aperture, and ISO. You cant control the light unless youre in a studio. The other threeshutter speed,

    aperture, and ISOyou can control, and these are known as the Exposure Triangle.

    The Exposure Triangle

    A relatively fast shutter speed of 1/250 of a second froze the motion of

    Nevada Falls in Yosemite, capturing the texture of the spray.

    A typical viewfinder exposure scale in manual

    mode, showing the shutter speed (250, or 1/250

    of a second) and aperture (5.6, or f/5.6).

    Shutter speed is the length of time the cameras shutter is open. The shorter the du-

    ration, the less light reaches the sensor, and the darker the photograph. The longer

    the time, the more light reaches the sensor, and the brighter the photograph.

    Shutter speeds are usually brief, mere fractions of

    a second: 1/60 of a second, 1/125 of a second, etc.

    But on most cameras all you see is that second

    number: 60, 125, 250, and so on. The first part of

    the fraction, the numerator (1/), is omittedyou

    just have to assume its there. So if you see the

    number 30, that means 1/30 of a second. If you

    see the number 60, that means 1/60 of a second.

    Theres an exception, of course, just to make

    things more complicated. When shutter speeds

    get really slowone second or longerwere

    not talking about fractions any more. When

    this happens, most cameras indicate this by put-

    ting the second symbol (") after the number.

    So 1" is one second; 2" is two seconds, etc.

    But unless you see that second (") symbol,

    youre looking at a fraction, and the higher

    the number, the shorter the shutter speed. The

    shorter the shutter speed, the less light reaches

    the sensor, and the darker the photograph.

    Shutter speed also affects movement, both of

    the camera and subject. A faster shutter speed

    (higher number) will freeze motion, allow-

    ing you to handhold the camera without blur,

    and get sharp images of moving subjects. A slow

    shutter speed, on the other hand, may require

    using a tripod to avoid camera shake, and will

    blur moving subjects. For more about shutter

    speeds and movement, see case studies 4 and 5.

    SHUTTER SPEED

    3

  • APERTURE

    The Exposure Triangle

    Every lens has a diaphragm that expands and

    contractslike the pupil in your eye. The

    size of this opening is the aperture. The big-

    ger the aperture, the more light reaches the

    sensor, and the brighter the photograph. The

    smaller the aperture, the less light reaches the

    sensor, and the darker the photograph.

    The numbers describing the size of this open-

    ing are called f-stops, and, unfortunately, they

    can be a bit confusing. With aperture, the bigger

    the number, the smaller the size of the open-

    ing. So f/2.8 is a large aperture (a large open-

    ing, letting in more light), while f/22 is a small

    aperture (a small opening, letting in less light).

    If you must know, f-stop numbers are actually

    ratios, or fractions. f/4 is 1:4, or 1/4. f/16 is 1:16,

    or 1/16. So the bigger the f-stop numbers, the

    smaller the fraction. (And if you really must

    know, the ratio is aperture to focal length.)

    But these details arent important. Just remember

    that with apertures and f-stops the numbers

    are inverted: a bigger number means a smaller

    opening, and less light, while a smaller number

    means a bigger opening, and more light.

    Aperture also affects more than just exposure.

    The larger the aperture (lower number), the less

    depth of field, while the smaller the aperture

    (higher number), the more depth of field. Or

    to look at it another way: bigger number, big-

    ger depth of field, smaller number, smaller

    depth of field. For more about aperture and

    depth of field, see case studies 2 and 3.

    A small aperture (f/22) kept both foreground and background

    in focus in this photograph from Death Valley.

    4

  • ISO

    The Exposure Triangle

    While shutter speed and aperture determine how

    much light reaches the sensor, ISO describes

    how the sensor reacts to that light. The higher

    the ISO number, the more sensitivity, and the

    greater the sensors light-gathering capacity.

    That extra sensitivity means that less light has to

    reach the sensor to create the desired exposure.

    This extra sensitivity has some big advantages.

    For example, by using a higher ISO, and gain-

    ing a faster shutter speed, you might be able

    to hand-hold the camera in dim light where

    you might otherwise need a tripod. Or, you

    could also freeze a subjects motion indoors,

    at dusk, or in other low-light situations.

    But this greater sensitivity comes at a price.

    The higher the ISO, the more noise youll get.

    Noise is like film graina distracting dot pat-

    tern across the photograph. High ISOs can also

    create other artifacts, like posterization, where

    smooth areas like sky or water become blotchy.

    So like many things in photographyand in life

    raising the ISO is a trade-off. A high ISO setting

    can give you the convenience of hand-holding, or

    allow you to freeze subject motion in dim light,

    but the image quality will suffer. In most situations

    you should use the cameras native ISO (usually

    100, but with most Nikon DSLRs the native ISO is

    200) to get the best image quality. But if you need

    that extra sensitivity, use itits better to have

    a grainy but sharp image than a blurred one.

    One more thing: avoid using the automatic ISO

    setting, as this can override your choices. If you set

    a faster shutter speed to darken the exposure, for

    example, the camera may boost the ISO to try and

    lighten the photograph back up! So you must turn

    off automatic ISO to have any control over exposure.

    STOPS

    Understanding this basic photographic terma stop (or f/stop)is essential

    to understanding exposure. Any time you double or halve the amount of light

    reaching the sensor, youve altered the exposure by one stop, or a full stop.

    Any time you double or halve the length of time the shutter is open, you

    double or halve the amount of light reaching the sensor, and therefore change

    the exposure by one full stop. A shutter speed of 1/125 of a second is twice as

    long as 1/250 of a second, and will allow twice the amount of light to reach

    the sensoror, in other words, it will increase the exposure by one stop. A

    shutter speed of 1/500 of a second is half the duration of 1/250 of a second,

    and will allow half the amount of light to reach the sensordecreasing the

    exposure by one stop.

    With the aperture the numbers get a little more complicated. A full-stop

    sequence goes like this: f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32. So

    doubling or halving the number is actually a two-stop change.

    Most cameras today have the shutter speed and aperture dials set to one-third

    stop increments. So rather than seeing the shutter speed jump from 30 to

    60 to 125 (1/30 to 1/60 to 1/125 of a second)full stopswhen you turn the

    shutter speed dial the numbers go from 30 to 40 to 50 to 60 to 80 to 100 to

    125a third of a stop for each click. With the aperture, you might go from 4 to

    4.5 to 5 to 5.6 to 6.3 to 7.1 to 8again, a third of a stop with each click.

    Now I dont know about you, but all these numbers are starting to make my

    head hurtand I do this stuff for a living. But all you have to remember is that

    each click of the dial changes the shutter speed or aperture by one-third of a

    stop, and you need to move the dial three clicks to make a full stop changeto

    double or halve the amount of light reaching the sensor.

    ISO also usually changes in one-third stop increments: 100, 125, 160, 200, 250,

    320, 400, etc. With ISO, doubling or halving the number doubles or halves the

    sensitivity of the sensora one stop change.

    5

  • Increasing the ISO to 1600 allowed me to use a fast shutter speed (1/250 of a second) to freeze the motion of these Ross geese in dim, pre-dawn light.6

  • Metering Modes

    Every modern camera comes with a built-in

    light meter to measure the light reaching the

    sensor. Most DSLRs have three or four metering

    modes. The default is usually a smart mode,

    which uses software algorithms to evaluate

    the light and dark areas within the viewfinder

    and guess the right exposure. Nikon calls this

    Matrix metering; Canon calls it Evaluative.

    Most DSLRs also have centre-weighted meter-

    ing, which measures the entire scene within the

    viewfinder, but with more emphasis on the centre.

    Many higher-end cameras also have a spot meter

    mode, which measures only the light from a small

    circle in the centre of the frame, or in an area

    that corresponds with your chosen focus point.

    Which mode should you use? Spot meters are

    tricky, and can throw your exposures way off if

    you dont know what youre doingwhich means

    understanding the Zone System. I talk about the

    Zone System in case study number 9, but in the

    mean time, choose either centre-weighted or one

    of the smart modes. The choice doesnt really

    matter, since, despite the manufacturers claims,

    the readings from centre-weighted metering are

    usually within a third of a stop of the smart modes.

    Any light meter will struggle with high-contrast scenes like this one of Yosemites Horsetail Fall.

    While meters are good starting points, histograms provide a more precise way of judging exposure.

    7

  • Exposure Modes

    Most DSLRs these days come with at least four

    exposure modes: program, aperture-priority, shutter-

    priority, and manual. Some also have modes for

    specific situationslandscapes, portraits, action, etc.

    What do these terms mean? Its actually pretty simple.

    In program mode, the camera takes the light meter

    reading and automatically chooses both the aperture

    and shutter speed. In landscape, portrait, or ac-

    tion modes the camera also chooses both shutter

    speed and aperture, but in an action mode it will fa-

    vour a faster shutter speed, while in landscape mode it

    will choose smaller apertures for greater depth of field.

    In shutter-priority mode, you pick the shutter speed,

    and the camera automatically selects the aperture

    based on the light-meter reading. In aperture-priority

    mode, you pick the aperture, and the camera au-

    tomatically selects the shutter speed, again based

    on the light-meter reading. In manual mode,

    you choose both the aperture and shutter speed,

    while the cameras light meter serves as a guide.

    Which mode should you use? All have their advan-

    tages and disadvantages, but if you really want to

    understand exposure you should learn to use manual

    mode. When you set both the shutter speed and

    aperture yourself youll gain a better understanding

    of how these fundamental photographic tools work.

    Youll begin to take control of your photographs rather

    than letting the camera make decisions for you.

    Once you have a solid understanding of manual

    exposure you can use shutter-priority or aperture-

    priority modes more effectively, because youll

    know whats happening under the hood.

    Because I think this is the best way to understand

    exposure, all the examples and exercises in this

    book will be geared to using manual mode. If

    youve never used manual exposure before, this

    might seem daunting, but trust me, its not that

    difficult, and youll thank me for it later.

    Learning to use manual mode will deepen your understanding of

    exposure and its fundamental components, allowing you to make good,

    quick decisions when trying to capture photographs like this.

    8

  • Reading Histograms

    With film, exposure always involves some guesswork. But with

    digital cameras you can tell immediately whether the right

    amount of light reached the sensor by looking at a histogram.

    This ability to instantly evaluate exposure is a game changer

    the single biggest advantage of digital photography over film.

    But many photographers are still guessing about exposure

    because theyre unable to decipher the histograms cryp-

    tic messages. Instead, they judge exposure by how bright

    the image looks on their cameras LCD screen. But while

    those little screens are extremely useful for many things,

    evaluating exposure isnt one of them. There are too many

    variables: screen quality (usually bad), the LCD brightness

    setting in the camera, and the amount of ambient light.

    A histogram is a much better way to judge exposureif

    you know how to read it. If you havent figured out

    how to display a histogram on the back of your cam-

    era, youll have to spend some quality time with that

    fascinating book, your cameras manual. Once you

    know how to view a histogram, what does it mean?

    A histogram is a pixel map. It shows how dark and light

    pixels are distributed within your photographlight

    pixels are on the right, dark pixels on the left. The shape

    of the histogram doesnt matter. In other words, dont

    worry if parts of the histogram shoot off the top, or

    whether theres a spike somewhere in the middle. The

    only sections that matter are the right and left edges.

    If any pixels are pushed up against the right edge, that

    means parts of the image are overexposedwashed out. If

    any pixels are pushed up against the left edge, that means

    parts of the image are underexposedblack. Most cameras

    also have an overexposure warningcommonly called the

    blinkieswhere overexposed parts of the photograph

    flash or blink. Some cameras also have an underexposure

    warning, which shows underexposed, black shadows.

    The most important parts of a histogram are

    the right and left edges. This histogram shows

    pixels pushed up against both edges, indicating

    overexposed highlights and underexposed shadows.

    A properly-exposed medium-contrast scene,

    with nothing pushed up against either end of

    the histogram.

    9

  • Handling High-Contrast Scenes

    In most scenes, you should be able to get detail in both

    highlights and shadows. That is, the histogram shouldnt

    touch either the right or left edge if you make the right

    exposure. But in some situations the contrast is too great

    for the cameras sensor to handle, so its impossible to avoid

    either washed-out highlights (a spike at the right edge of

    the histogram), black shadows (a spike at the left edge of

    the histogram), or both. In these cases, its usually better to

    retain detail in the highlights and sacrifice shadow detail.

    When looking at the histogram, its better to have pixels

    pushed up against the left edge than the right edge.

    Why are highlights usually more important than shad-

    ows? First, our eyes are drawn to bright areas, so view-

    ers immediately notice if theyre overexposed. Second,

    in real life we can always see detail in bright spots, but

    we cant always see detail in shadows. It seems un-

    natural to find washed-out highlights in a photograph,

    yet it feels perfectly normal to see regions of pure black.

    So if you cant have both, 90 percent of the time you

    should sacrifice the shadows and keep the highlights. In

    most photographs, the lightest pixels should be close to

    the right edge of the histogram, but not touching it.

    Histogram for a high-contrast scene with a spike at

    the right edge, indicating overexposed highlights.

    Histogram for a high-contrast scene with pixels pushed up

    against the left edge, indicating underexposed shadows, but

    properly exposed highlights. In most cases this is preferableif

    you cant get both, its better retain detail in the highlights and

    let the shadows go black.

    10

  • The Short Answer

    This bears repeating: most of the time, the lightest pixels should be close to the right edge of the histogram,

    but not touching it. If theres a large gap between the lightest pixels and the right edge of the histogram,

    the photograph is underexposed. If any pixels touch that right edge, the photograph is probably over-

    exposed. For most images, just make sure the lightest pixels dont touch the right edge, but are near it.

    There are two main exceptions to this. First,

    when the photograph includes the sun itself, or

    the sky next to the sun, its okay for these areas

    to be overexposed. Theyre too bright to see

    in real life, so its okay if such areas lack detail

    in photographsit looks natural. The blink-

    ies come in handy here: while the histogram

    tells you that something is overexposed, the

    blinkies show which parts of the image are

    washed out, and how large those areas are.

    Second, with digital photography its possible to

    blend two or more exposures together with Pho-

    toshop or HDR software to capture both highlight

    and shadow detail, even in high-contrast scenes.

    In these cases you still want to capture one image

    with the lightest pixels near, but not touching,

    the right edge of the histogrambut then also

    make one or more lighter exposures, including

    one with nothing pushed up against the left edge

    of the histogram. This ensures that you have

    shadow detail as well, and all the image informa-

    tion you need to blend these exposures together in

    software. For more about this, see case study 10.

    So now that you understand the basicsshut-

    ter speed, aperture, ISO, histogramsits

    time to look at some examples and apply

    this knowledge to real-life situations.

    Underexposed

    the brightest pixels

    arent close to

    the right edge of

    the histogram.

    Overexposed

    a spike at the

    right edge of

    the histogram.

    Proper exposure

    the brightest

    pixels near, but

    not touching, the

    right edge of

    the histogram.

    11

  • Case Study 1: Sierra AspensUSING THE HISTOGRAM TO FIND THE RIGHT EXPOSURE

  • Backlight made these aspen leaves glow, but

    the sun was sinking behind a ridge, and I knew

    I had just minutes to capture this scene. With

    a still subject, and the camera on a tripod, the

    shutter speed didnt matter. The scene had

    moderate depth, so I started by setting a mid-

    dle aperture of f/11. With that f-stop, centre-

    weighted metering, in manual exposure mode

    at 100 ISO, the meter indicated a shutter speed

    of 1/60 of a second. But when I took the photo

    the aspens looked washed out on the cameras

    LCD screen, the histogram showed a spike

    at the right edge, and there were small areas

    of blinkies in the brightest leaves, indicating

    that parts of the image were overexposed (A).

    I quickly turned the shutter speed dial three

    clicks to the right to 1/125 of a second, one

    stop faster (and darker) than 1/60and pressed

    the shutter button again. Much better! The

    histogram showed pixels near, but not touch-

    ing, the right edge, while the aspens had

    better colour, and stood out dramatically from

    the darker background (BFollowing page).

    Now I suppose some people might prefer the

    lighter version. Exposure, like everything in

    photography, is subjective. Theres really no

    such thing as the correct exposuretheres

    only the exposure that works best for you, and

    captures the scene the way you visualize it.

    What caught my eye here was the contrast

    between the sunlit aspens and the shaded

    background. I wanted that background to be

    dark so the yellow leaves would stand out

    clearly. And I certainly didnt want those

    leaves to look faded and washed out, since

    theyre the focal point of the image. So an

    exposure one stop darker than the meter

    reading gave me what I was looking for.

    Now why did the meter get this one wrong

    (for me at least) in the first place? Because

    light meters are dumb, of course! With centre-

    weighted or smart modes, the meter is

    simply measuring the amount of light reflect-

    ing back at the camera, and averaging the

    light and dark tones together. It doesnt know

    what parts of the scene are important to you.

    Also, meters dont know whether theyre

    pointed at something white, or black, or in-

    betweenthey just measure the amount of

    light reflected back at them. Naturally, white

    objects reflect more light than black objects.

    Since meters are calibrated to middle grey

    theyre easily fooled by anything that isnt a

    medium tone or colour. The tendency is for the

    meter to try to lighten dark objects and darken

    light objectsto make them middle grey.

    A

    USING THE HISTOGRAM TO FIND THE RIGHT EXPOSURECase Study 1: Sierra Aspens

    13

  • In this scene, when averaging everything

    together, the meter gave more weight to the

    shaded areas and tried to lighten them to

    a middle tone. Unfortunately that pushed

    the most important part of the scenethe

    treestoo high, and they became washed

    out. So I had to deviate from the meter read-

    ing and set an exposure one stop darker. The

    meter got me closejust not close enough.

    In this case I used a faster shutter speed

    to darken the exposure. I could have used

    a smaller aperture (bigger f-stop number)

    instead, and here either would have worked.

    But when using a tripod with a stationary

    subject I usually set the aperture first to get

    the desired depth of field, and then adjust

    the shutter speed to get the right exposure.

    I could also have done the exact same thing

    in aperture-priority automatic mode. At f/11,

    100 ISO, in aperture-priority mode, the camera,

    guided by the same light meter (and with no

    exposure compensation), would have chosen

    the same shutter speed: 1/60 of a second. After

    looking at the histogram I could have used

    the exposure-compensation dial to darken the

    image by one stop. In aperture-priority mode

    the f-stop would have stayed the samef/11

    but the camera would have chosen a faster

    shutter speed: 1/125 of a second. Which is

    exactly what I ended up with in manual mode.

    See how understanding manual exposure

    will allow you to use automatic modes more

    intelligently? When you adjust the exposure-

    compensation dial in aperture-priority mode,

    what youre really doing is changing the

    shutter speed. When you turn the dial to -1.0,

    youre telling the camera to use a faster shutter

    speed to darken the exposure. When you set

    the compensation to +1.0, youre telling the

    camera to use a slower shutter speed to let in

    more light and increase the exposure. If youre

    hand-holding, a faster shutter speed would

    be fine, but a slower shutter speed might lead

    to camera shake. So if you use any automatic

    exposure mode, you need to pay attention

    to what its doing. Better yet, use manual

    mode so youre conscious of all the settings.

    By the way, live view can be a great as-

    set for finding the right exposureif you

    can see a histogram. Using a histogram

    in live view, I could have ignored the

    cameras meter and dialed in the right

    shutter speed before taking the picture.

    USING THE HISTOGRAM TO FIND THE RIGHT EXPOSURECase Study 1: Sierra Aspens

    B

    14

  • PHOTOGRAPH BOTH LOW AND HIGH-CONTRAST SCENES

    Case Study 1: Sierra Aspens

    1) First, use a tripod so you dont have to worry about

    camera shake. Then set the aperture. Pick a middle f-stop

    like f/8 or f/11 if depth of field is not an issue. Pick a small

    aperture like f/16 or f/22 if you have both near and distant

    objects in the frame (more about depth of field in the

    next example).

    2) Use centre-weighted or smart metering to set the

    shutter speed. Most cameras show an exposure scale in

    manual mode. Simply turn the shutter speed dial until the

    exposure indicator lines up with zero.

    3) Then take a photo and check the histogram. If it looks

    okayif the brightest pixels are near, but not touching, the

    right edge, and you dont see any blinkiesthen youre

    done. If not, adjust the shutter speed. If you see a spike

    at the right edge of the histogram, or you see blinkies,

    that means the image is too light, so use a faster shutter

    speed to darken the exposure. If the histogram is pushed

    to the left, and theres a large gap between the brightest

    pixels and that right edge, then use a slower shutter

    speed to lighten the exposure. Then take another photo,

    and if necessary, keep adjusting until the image and the

    histogram look right.

    Remember that on most cameras, each click of the

    shutter speed dial changes the exposure by only a third

    of a stop, which is hardly noticeable. To see a significant

    difference, click the dial three times to change the

    exposure by one full stop. And once youve made the first

    exposure, ignore the meter and use the histogram to guide

    your adjustments.

    If you dont have a tripod, start by setting a reasonably

    fast shutter speed, like 1/125 of a second, then adjust the

    aperture until the exposure indicator lines up with zero. If

    the initial histogram is off, keep adjusting the aperture to

    change the exposure until you get it right.

    With the high-contrast scene, when you get the histogram

    into the right spotnear, but not touching, the right

    edgethe photo might look too dark on your cameras

    LCD screen. Thats okay; exposure for high-contrast

    scenes is often a compromise, and youll probably like the

    seemingly too-dark exposure better when you see it on

    your computer screen. But just in case, it wouldnt hurt to

    take a lighter one!

    PHOTOGRAPH TWO DIFFERENT SUBJECTS: ONE HIGH-CONTRAST SCENE WITH A MIXTURE OF SUN AND SHADE, AND ONE LOW-CONTRAST SCENE WHERE EVERYTHING IS IN THE SAME LIGHT. USE MANUAL MODE, AND FOLLOW THESE STEPS:

    EXERCISE

    15

  • Case Study 2: Three BrothersGETTING EVERYTHING IN FOCUS

  • Now that you have a better understanding of how to

    read a histogram and adjust the exposure manually, its

    time to take a closer look at one of the fundamental

    exposure controls: the aperture. In addition to altering

    exposure by controlling how much light passes through

    the lens, the aperture also affects depth of field.

    What is depth of field? Its how much of the im-

    age is in focus from front to back. You can have

    one thing in focus, while everything in front of or

    behind that object is out of focus. Or you can try

    to make every part of the photograph sharp.

    With most landscape images, I want everything to be in

    focus. But in this scene of Three Brothers in Yosemite the

    depth of field was extremethe snow mounds at the bot-

    tom of the frame were only two or three feet from the cam-

    era, while the background peaks were at least a mile away.

    I knew this photograph would require a small aperture

    the smaller the aperture, the more depth of field. Is f/22

    a small aperture or a large one? What about f/4? Heres

    an easy way to remember: the greater the f-stop number,

    the greater the depth of field; the smaller the f-stop

    number, the smaller the depth of field. So a large num-

    ber, like f/16 or f/22, means great depth of field; a small

    number, like f/4 or f/5.6, means shallow depth of field.

    Wide-angle lenses have inherently greater depth of field,

    and I wanted the near-far perspective they create, so I

    chose a 24mm focal length. With the camera on a tripod,

    and the subject sitting still, I didnt need to worry about

    using a slow shutter speed, so I started by setting my lens

    to its smallest aperture: f/22 (big number, big depth of

    field). Then I focused manually using the procedure in

    the sidebar Focusing for Maximum Depth of Field.

    Next, as in the last example, I set the shutter speed to

    the light meters recommendation: 1/30 of a second (at

    100 ISO). This turned out to be just rightthe histogram

    looked perfect. Although this scene had a lot of contrast,

    apparently the light and dark areas balanced out.

    To get great depth of field, use a wide-angle lens,

    focus carefully, and set a small aperture like

    f/16 or f/22. A tripod helps, as the small aper-

    ture usually requires a slow shutter speed.

    GETTING EVERYTHING IN FOCUSCase Study 2: Three Brothers

    17

  • FOCUSING FOR MAXIMUM DEPTH OF FIELDCase Study 2: Three Brothers

    FOCUSING IS CRITICAL WHEN TRYING TO GET MAXIMUM DEPTH OF FIELD. FOCUS ON THE FOREGROUND AND THE BACKGROUND WILL LOOK SOFT. FOCUS ON THE BACKGROUND AND THE FOREGROUND WILL BE BLURRED. THE OPTIMUM FOCUSING POINT (HYPERFOCAL DISTANCE) IS SOMEWHERE IN BETWEEN. TO FIND IT, FOLLOW THESE STEPS:

    a) Use manual focus, then first focus on the object closest to

    the camera, and note the distance on your focusing ring. In this

    illustration, its three feet away.

    b) Next, focus on the farthest thing from the camera, and

    once again check that distance on your focusing ring.

    Here its at infinity.

    c) Set your focus halfway between these two spots on your

    focusing ring.

    18

  • Case Study 3: ConeflowersUSING SHALLOW DEPTH OF FIELD

  • Standing among these tall coneflower stalks, I looked for a way to simplify

    the scene. The obvious solution was to make a portrait of one flower,

    while using a wide aperture to throw the background out of focus.

    I knew that the more distant the background, the more out of focus

    it would be, so I looked for an angle where the background flow-

    ers were several feet away from my main subject. I also knew that

    the inherently shallow depth of field of a telephoto lens would help

    throw the background out of focus, so I used a 200mm lens.

    With this lens set to its widest aperture, f/4 (small number, small

    depth of field), the background looked nice and soft, but some

    of the petals on the main flower were out of focus. I tried stop-

    ping down the aperture to f/8, but when I pressed my depth-of-field

    preview button the background flowers started to come into fo-

    cus, and became too distracting. So I kept the aperture at f/4.

    With images like this at least one important visual focal point needs

    to be sharp, so I focused manually on the green button at the top

    of the flower. The contrast was low, making this an easy exposure. I

    manually set the shutter speed to the meters recommendation, 1/15

    of a second (at 100 ISO), and this turned out to be just right.

    USING SHALLOW DEPTH OF FIELDCase Study 3: Coneflowers

    20

  • DEPTH-OF-FIELD PREVIEW

    Case Study 1: Sierra Aspens

    When you look through the viewfinder of an SLR camera,

    youre not always getting an accurate view of whats in

    focus. Even though you may have the aperture set to f/16,

    the diaphragm in the lens stays wide open at f/2.8 or f/4 (or

    whatever the lowest f-stop number is on your lens) until you

    press the shutter. Then the mirror flips up, the diaphragm

    closes down to f/16 (or whatever aperture youve set), and

    the shutter opens.

    This design allows plenty of light to come through the lens,

    and makes the viewfinder nice and bright when youre trying

    to compose and focus. But you dont see an accurate view of

    the depth of field unless youre using the widest apertureor

    you use the depth-of-field preview.

    The depth-of-field preview is a button somewhere on the

    camera (usually near the lens mount) that doesnt seem

    to do anything except make the viewfinder go dark. But it

    does have a function: pressing the button closes down the

    aperture to f/11, or f/16, or whatever its set to, so that you

    can actually see whats in focus through the viewfinder at

    that f-stop.

    Of course because youve closed down the aperture, less

    light is coming through the lens, so the viewfinder gets

    really dark! Nevertheless, it can still help you determine

    whether youve really got everything in focus in landscape

    photographs, or whether background elements have become

    too distracting with close-ups or portraits.

    In this first shooting-star photograph (A), I kept the aperture

    nearly wide-open at f/5.6. The background was nice and soft,

    but some of the flowers were out of focus. In the second

    example I stopped the aperture down to f/16 (B). With the

    depth-of-field preview I could see that most of the flowers

    were in focus, but some background leaves had become

    visible. Which is better? Thats always subjective, of course.

    In this case it bothers me that some flowers are out of focus

    at f/5.6, so I probably prefer the greater depth of field at

    f/16, even though the background is more distracting.

    Make two different photographs, one with shallow depth of field to isolate the subject, and one with

    great depth of field where everything is in focus from near to far.

    For the shallow depth-of-field image, use a telephoto lens (the longer the better), make sure at least

    one thing is sharp, and use a wide aperture like f/2.8 or f/4 to throw the background out of focus.

    For the photograph with great depth of field, use a wide-angle lens and make sure everything is

    sharp. You should have an object very close to the camerano more than 5 feet awayplus something

    distantat infinityand use a small aperture like f/16 or f/22 to get everything in focus. Use the

    focusing technique I describe in Focusing for Maximum Depth of Field, page 18.

    EXERCISE CONTROLLING DEPTH OF FIELD

    A B

  • Case Study 4: Upper Yosemite FallFREEZING MOTION

  • Both shutter speed and aperture control the

    exposurehow bright the image is. Aperture,

    as weve seen, also affects depth of field. Shut-

    ter speed, on the other hand, affects move-

    mentboth camera movement and subject

    movement. Faster shutter speeds freeze motion,

    while slower shutter speeds blur motion.

    For getting sharp hand-held photos, the shut-

    ter speed should be equal to or greater than the

    length of the lens. So if youre using a 20mm lens,

    the shutter speed should be 1/20 of a second or

    faster. If youre using a 100mm lens, the shutter

    speed should be at least 1/100 of a second. With

    image stabilization, you may be able to get away

    with slower shutter speeds than this, but you

    can get sharp photos at any shutter speed with

    a sturdy tripodunless the subject is moving.

    Photographing Upper Yosemite Fall one spring

    afternoon, I was struck by the patterns and

    textures of the water. Gusts of wind would

    blow the fall almost sideways, causing ar-

    rows of spray to shoot out underneath.

    The camera was on a tripod, but I needed a fast

    shutter speed to freeze the waters motion and

    show its texture. How fast? The answer depends

    on how quickly the subject is moving across

    the picture. A relatively slow shutter speed

    can freeze something moving toward you or

    away from you, but the same object moving

    across the frame may need a much faster shut-

    ter speed. Experience is the best teacher, but a

    zoomed-in look at your LCD screen can help.

    This scene had little depth, but shutter speed

    was obviously important, so I set that first. Previ-

    ous experience told me that 1/125 of a second

    would be fast enough to freeze the waters mo-

    tion. Then, with the ISO at 100, I adjusted the

    f-stop until the meter indicated I had the correct

    exposure (which happened to be at f/8). But

    the meter was apparently fooled by all the dark

    shadows, and the resulting histogram had a spike

    on the right edge, while the waterfall looked

    washed out and showed lots of blinkies (A).

    FREEZING MOTIONCase Study 4: Upper Yosemite Fall

    A

    23

  • Since shutter speed was the primary consideration I left that alone, and turned the aperture

    dial three clicks to the right (one full stop) to f/11. (On most cameras, turning either the

    shutter speed or aperture dial to the right darkens the photo, while turning them to the

    left lightens it.) I made another test shot, and this time the histogram looked perfect.

    Then I just had to wait for the right moment (B).

    Of course, fast shutter speeds can freeze the motion of many subjects: flying birds, people

    in action, cars, planes, etc. To freeze movement, start by selecting a fast shutter speed

    usually 1/125 of a second or fasterthen use the aperture to adjust the exposure.

    Case Study 4: Upper Yosemite Fall RECIPROCITYShutter speed and aperture have a reciprocal relationship. If you reduce the amount of

    light coming through the lens (aperture) by one stop, but increase the time the shutter

    is open by one stop, the same amount of light will reach the sensor. This means you

    can use several different combinations of shutter speed and aperture to get the same

    exposure. All of the following combinations will allow an equal amount of light to reach

    the sensor:

    1/250 at f/2.8

    1/125 at f/4

    1/60 at f/5.6

    1/30 at f/8

    1/15 at f/11

    1/8 at f/16

    1/4 at f/22

    Which combination you choose depends on whether you want more depth of field or

    less, a faster shutter speed or a slower one.

    Usually you should start with the most important setting. If depth of field is more critical

    than motion, set the aperture first, then use whatever shutter speed will give you the

    right exposure. If either camera or subject movement is a concern, set the shutter speed

    first, then dial in the aperture that gives you the exposure you want.

    If, however you want the fastest shutter speed possible for the available light, start by

    setting the lowest f-stop number on your lens. This wide aperture will pass more light

    through the lens, and allow you to use a shorter shutter speed. If you want the slowest

    shutter speed possible for the available light, start by setting your highest f-stop number

    (and lowest ISO). This small aperture will minimize the light reaching the sensor, and

    require a long shutter speed to get the right exposure.

    If neither shutter speed nor aperture mattersif the camera is on a tripod, the subject

    isnt moving, and the scene has little depthstart by setting a middle f-stop like f/8 or

    f/11, as most lenses are sharpest at medium apertures.

    B

    24

  • Case Study 5: Wildcat FallBLURRING MOTION

  • While a fast shutter speed can emphasize the texture

    and power of large waterfalls, a slow shutter speed

    often works better for small cascades. Photographing

    this scene in Yosemite, I wanted to blur the motion

    of the water to give it an ethereal look and create

    contrast between smooth water and rough rocks.

    After finding a nice balanced composition, I put

    the camera on a tripod (I wanted the water to be

    blurred, not the rocks), then added a polarizing

    filter to cut reflections on the wet rocks and make

    the white water stand out. Next I selected the

    smallest aperture on my 1740mm zoom: f/22.

    If I wanted to blur the water, why did I set the aperture

    first, rather than the shutter speed? First, there was a

    lot of depth herethe rock in the lower-left corner was

    only a few feet from the cameraso I needed a small

    aperture to get everything in focus. But even if depth

    wasnt an issue, when blurring motion I routinely start

    with my lowest ISO and smallest aperture, as this will

    give me the slowest shutter speed possible for the light-

    ing conditions. The less light coming through the lens,

    the longer the shutter speed has to be to give you the

    right exposure. (Adding a polarizing filter or neutral-

    density filter can slow the shutter speed even more if

    necessary, as when trying to blur motion in direct sun.)

    How slow a shutter speed do you need to blur motion?

    That depends on how fast the subject is moving across

    the frame. For flowing water, 1/2 a second or slower

    will usually give the water that soft, silky appearance.

    But sometimes a slightly faster shutter speed, like 1/4 or

    1/8, looks better, giving the water a bit more texture.

    For this scene, at f/22 with 100 ISO, the meter indicated

    a shutter speed of 1.3 seconds, which seemed perfect

    nice and slow. I made a test exposure, and the histogram

    looked good: near, but not touching, the right edge.

    The world is in constant motion, and many situa-

    tions can lend themselves to slow shutter speeds.

    Ive blurred wind-blown moonlit clouds during

    a six-minute exposure, and panned with flying

    birds at 1/15th of a second. Use your imagina-

    tion, and dont be afraid to experiment.

    BLURRING MOTIONCase Study 5: Wildcat Fall

    Photograph two different moving subjects, one using a fast shutter speed to

    freeze motion, the other with a slow shutter speed to blur the movement.

    Its easier to freeze motion in bright light, and easier to blur motion in low

    light like shade or dusk. To blur motion, either set the camera on a tripod

    and let the subject move through the frame, or try panning, where you

    follow the subject with your camera while blurring the background behind

    it. Either way, try different shutter speedsevery situation is unique, and

    often one speed will be just right.

    EXERCISE FREEZE AND BLUR MOTION

    26

  • Case Study 6: Stormy Afternoon at Mono LakePUSHING THE ISO

  • In some photographs, shutter speed is the most impor-

    tant consideration. In other cases, aperture and depth

    of field are the biggest concerns. But what if both are

    important? What if you need a fast shutter speed and

    great depth of field? Then its time to push the ISO.

    By raising the ISO you amplify the light signal reaching the

    sensor, allowing you to use a faster shutter speed, smaller

    aperture, or both. This can be extremely valuable when try-

    ing to handhold the camera or freeze motion in low light.

    But like many things in photography, and in life, theres a

    trade-off: the higher the ISO, the more noise youll get.

    However, every year cameras and noise-reduction soft-

    ware get better, and its sometimes possible to get amaz-

    ing results at high ISOs. To test your cameras limitations,

    try shooting with high ISO settings and take a zoomed-in

    look at the images on your computer. Better yet, make

    some large prints and see how apparent the noise is.

    I made this image of Mono Lake with a Canon 1Ds Mark

    II, which, as I write this, is a seven-year-old modelan-

    cient technology by todays standards. But it has a

    full-frame sensor, which helps; in general, the larger the

    sensor, the better it handles noise. And noise-reduction

    software has improved immenselyIve made virtually

    noise-free images with this camera at 1600 ISO.

    In this wide-angle composition I figured that f/16 would give me

    enough depth of field to keep the foreground waves and distant

    tufa towers in focus. At 100 ISO the meter indicated 1/30 of a

    second, which was too slowthe waves would be blurred. So I

    set the shutter speed to 1/125 of a second,

    figuring that would be the minimum speed neces-

    sary to freeze the motion. Then I simply pushed

    up the ISO until the meter indicated I had the cor-

    rect exposure (which happened to be at 400 ISO).

    A test exposure showed a perfect histogram, with

    the brightest pixels near, but not touching, the

    right edge, and no blinkies. That meant I could

    leave the settings alone and concentrate on try-

    ing to catch the waves in the right position.

    With ISO, doubling the number increases

    the exposure one stop. So increasing the

    ISO from 100 to 200 gained one stop of

    extra light sensitivity; pushing the ISO further

    to 400 gained another stop, for a total of two stops. That

    allowed me to shorten the shutter speed from 1/30 of a

    second to 1/125 of a second, a two-stop difference.

    But you dont have to calculate this stuffjust do what I did:

    set the shutter speed and aperture you want, then increase the

    ISO until you get the right exposure. Youll get more noise,

    but Id rather have a little noise than a blurry photograph.

    PUSHING THE ISOCase Study 6: Stormy Afternoon at Mono Lake

    28

  • Case Study 7: Grey Pines after a SnowstormHIGHLIGHT RECOVERY, AND EXPOSING TO THE RIGHT

  • Usually you want the brightest pixels to be

    near, but not touching, the right edge of

    the histogram. This is called exposing to

    the right (ETTR for short), as youre trying

    to push the histogram as far to the right as

    possible without losing highlight detail.

    By making the photograph as light as possible,

    but not washed out, you get the maximum pos-

    sible shadow detail. Also, in a digital file theres

    actually less information in lower values, making

    those low valuesthe shadowsmore prone to

    noise and posterization. So the lighter you make

    those shadows, the less noise youre likely to see.

    With raw files its often possible to recover seem-

    ingly overexposed highlights in software. Because

    of that, some ETTR devotees actually suggest

    deliberately overexposing your photographs. I

    dont recommend that, because even if you can

    recover those highlights its sometimes impossible

    to make that overexposed image look rightto

    give it the appropriate tones, colour, and con-

    trast. But that ability to recover overexposed

    highlights does give you a bit more latitude,

    and, at least with some cameras, allows you to

    be less concerned about small areas of blinkies.

    Photographing these grey pines in the Sierra

    Nevada foothills, with my 70200mm zoom

    lens on a tripod, and the ISO set to 100, I di-

    aled in an aperture of f/22 (my sharpest f-stop

    for that lens), and used the shutter speed the

    light meter recommended: 1/20 of a second.

    I took one frame, then checked the imageand

    saw some blinkies, and a small spike at the right

    edge of the histogram (A). I quickly dialed in a

    faster shutter speed1/30 of a secondand kept

    shooting, but the mist had already shifted, and

    it turned out that this first frame was the best.

    HIGHLIGHT RECOVERY, AND EXPOSING TO THE RIGHTCase Study 7: Grey Pines after a Snowstorm

    A

    30

  • Fortunately it was easy to bring back detail in those washed-out high-

    lights with Lightrooms Recovery tool. The zoomed-in view shows

    an area of overexposed mist in the upper-right portion of the image

    (B). After pushing the Recovery slider to the right (to +17), you can

    see detail in this formerly blank area (C). The final image has good

    overall contrast, and detail in both highlights and shadows (D) .

    With my camera (Canon 1Ds Mark II), I dont worry about

    small areas blinking on my LCD screen, as I know these can

    be recovered later. But keep in mind that this only works

    with raw files, and not with every camera. Try the exercise

    on the next page to see if it works with your model.

    HIGHLIGHT RECOVERY, AND EXPOSING TO THE RIGHTCase Study 7: Grey Pines after a Snowstorm

    B C

    D

    31

  • Case Study 7: Grey Pines after a Snowstorm

    Find a scene with some white or near-white areas,

    like clouds, snow, a white building, or a person

    with a white shirt. Make sure that white object is

    the brightest thing in the frame (i.e., you dont

    want your white subject to be in the shade, while

    other areas of the photo are in the sun).

    Its best to do this exercise on a tripod, with a still

    subject, so that motion isnt an issue. With the

    camera set to raw mode, find the theoretically

    correct exposure, with the brightest pixels near,

    but not touching, the right edge of the histogram,

    and no blinkies. Then make an exposure one-third

    of a stop brighter by setting a slower shutter

    speed. Repeat that five more timesin other

    words, increase the exposure by one-third stop

    increments six times total, until youve gone

    two full stops brighter than the theoretically-

    correct exposure.

    Download the images and look at them in your

    favourite raw-processing software. (It really

    helps to be using a good, calibrated monitor!)

    First, compare the histograms and highlight

    alerts (blinkies) of the images on your camera

    to the ones on your monitor. You may find some

    differences: an image with a good-looking

    histogram on the camera may turn out to be

    overexposed when you view it on your computer,

    or vice-versa. Knowing these differences can help

    you make adjustments in the field.

    Next, try using the Recovery or Highlight

    Recovery tool in your software on some of the

    overexposed images. Zoom in on the

    washed-out areas and see if youre actually

    recovering detail and texture, or just making

    these areas look grey. Also, look for uneven,

    blotchy tones in the highlights.

    With most modern DSLRs youll probably find

    that you can recover detail in highlights that are

    as much as a stop overexposedperhaps even

    more. But with some cameras the limits may

    be less. Or you might find that you can recover

    detail, but you see abrupt transitionsthat

    blotchy look I mentioned.

    Armed with this new knowledge you may become

    less concerned about small, overexposed areas

    in your photographsor you could realize that

    you have to be really careful to not overexpose

    anything. But either way, youll know.

    So far Ive just talked about the overall histogramthe

    luminance histogram. But most cameras also have the

    ability to display histograms for the red, green, and

    blue colour channels separately.

    Do you need this? In most cases, no. But sometimes,

    when photographing a sunset sky, red or yellow

    flowers, or any highly-saturated colours, one of the

    colour channels will be overexposed, and you wont

    see that in the luminance histogram, nor will the

    blinkies warn you about it.

    Overexposing one channel could make some colourful

    highlights look blotchy, or lack detail. With raw files

    you may be able to recover this detail, but you may

    notit depends on the camera, and how overexposed

    that channel is. So when photographing colourful

    subjects, its a good idea to look at the RGB histogram,

    and if one of the channels shows a spike on the right

    side, make a darker exposure.

    EXERCISE TEST THE LIMITS OF HIGHLIGHT RECOVERY

    RGB HISTOGRAMSAn RGB histogram showing an

    overexposed red channel, with

    a spike at the right edge.

  • Case Study 8: Oaks and Mist, AutumnINCLUDING THE SUN IN THE FRAME

  • I usually dont want any part of a photograph to be overexposed.

    We never see washed-out highlights in real life, and it looks unnat-

    ural to see them in a photograph. But theres one major exception:

    you cant see detail in the sun itself, because its too bright. In fact,

    if you stare at it too long youll damage your eyes! So when you

    include the sun in a photograph, or sunlight reflecting off water

    or glass, it seems perfectly normal for these areas to lack detail.

    The sun shining through the mist from behind these oak

    trees was beautiful, but the contrast was extreme, and I

    had to avoid lens flarethe distracting coloured spots

    created when the sun hits the front of your lens.

    In situations like this I try to get just the edge of the sun poking

    out from behind a branch or trunk. This makes the bright sun a

    focal point, but blocks the flare. So I positioned my camera (on a

    tripod of course) so that the sun was hidden behind a tree branch,

    figuring that the sun would edge into view by the time I was ready.

    I set the aperture to f/16, which seemed sufficient to get both

    the yellow foreground plants and trees in focus. Small apertures

    also create a starburst effect when you include the sun in the

    frame. At 100 ISO I dialed my shutter speed to the meters rec-

    ommendation, 1/60 of a second, and made a test exposure.

    INCLUDING THE SUN IN THE FRAMECase Study 8: Oaks and Mist, Autumn

    A

    34

  • Unfortunately the histogram didnt help much, since theres

    bound to be a spike at the right edge from the sun and adjacent

    areas. In these situations I judge the exposure by the amount

    of blinkies. A small amount of blinkies in and around the sun

    is fine. More than that, and the image is probably overexposed.

    If just the sun itself is blinking, its probably underexposed.

    My test exposure showed a small amount of blink-

    ies around the sun, so this seemed right. But to hedge

    my bets I set the camera to auto bracket three exposures:

    the middle, or base exposure (1/60 of a second), plus one

    stop lighter and one stop darker (1/30 and 1/125).

    Now I almost hesitate to mention bracketing, as some people

    will take this as a license to be sloppy with their exposures

    and just bracket the heck out of every scene. But wild bracket-

    ing doesnt work with moving subjectsyou have to get the

    exposure right at the instant the subject is in the perfect posi-

    tion. And even with static subjects, mindless bracketing may

    not be enough: you could bracket one stop lighter and one

    stop darker than the meter recommends, when the right expo-

    sure is actually three stops darker than the meter suggests.

    INCLUDING THE SUN IN THE FRAMECase Study 8: Oaks and Mist, Autumn

    B

    35

  • But in difficult situations, intelligent bracketing can help.

    By intelligent I mean that you use the histogram and blink-

    ies to help you make the best exposure you can, but hedge

    your bets by making lighter and darker exposures as well.

    With this scene I knew that my test exposure (1/60 at f/16) was

    close, and by making exposures one stop light and darker I would

    be sure to get it right. When the sun edged out from the behind

    the branch I bracketed three quick exposuresclick click click.

    The middle exposure turned out to be the best (A Page

    34). Small areas in and around the sun are washed out, but

    that seems normal and natural, and the rest of the tones

    in the photograph look about right. Most importantly, the

    sunbeams cutting through the fog stand out clearly.

    The lighter exposure looks washed out (B Previous

    Page), while the darker one seems murky (C). The blink-

    ies cover too large an area in the lighter version, and are

    barely visible in the darker one. Again, the middle expo-

    sure, with some blinkies, but not too many, seems best.

    So when the sun is in the frame, its okay to see some

    washed-out areasas long as theyre not too big.

    INCLUDING THE SUN IN THE FRAMECase Study 8: Oaks and Mist, Autumn

    C

    36

  • Case Study 9: Unicorn PeakSPOT METERING AND THE ZONE SYSTEM

  • With film, the Zone System is the best way

    to get accurate exposures in a wide variety of

    situations. With a digital camera, where you

    can check the exposure with the histogram,

    the Zone System is less essential. But the ex-

    posure methods Ive described so far involve

    some trial and error; the Zone System will

    lead you to the perfect exposure more quickly.

    With practice you should get it right on your

    first try at least 90 percent of the time.

    Volumes have been written about the Zone

    System, but Im going to describe a simple

    method of applying the Zone System to

    digital capture in just a couple of pages.

    First, while Ansel Adams and Fred Archers

    original Zone System had eleven zones, zero

    through ten, were going to concentrate on

    just the middle ones, three through seven.

    Zone 5 represents a mid-tone in the scene.

    Anything one stop darker is zone 4, two stops

    darker zone 3, and so on. Anything one stop

    lighter is zone 6, two stops lighter zone 7, etc.

    Zones 3 and 7 are important because they

    represent the limits of most digital cameras.

    Zone 2 is too dark to show detailessentially

    black. Zone 8 is too light to show good de-

    tailwashed out. So Zones 3 and 7 are the

    lower and upper limits for retaining detail

    and texture (though cameras vary, and some

    high-end models may go beyond this).

    SPOT METERING AND THE ZONE SYSTEMCase Study 9: Unicorn Peak

    Zone 2

    A hint of detail.

    Zone 3

    Dark, with good detail.

    Zone 4

    Dark tone or colour.

    Zone 5

    Middle tone,

    medium colour.

    Zone 6

    Light tone or

    pastel colour.

    Zone 7

    Light, with texture.

    Zone 8

    A hint of detail,

    but essentially

    washed out.

    38

  • Okay, enough backgroundhow do you use it? The

    simplest approach to the Zone System concentrates

    on highlights and ignores shadows. Start by picking

    the most important highlight. Whats important? Not

    a tiny spot, and not something that lacks detail, like

    a blank sky. Pick the brightest significant part of the

    photograph that needs to have detail and texture.

    In this scene from Yosemites high country, the

    brightest significant highlights were the cloud at

    the top of the frame and the patch of white wa-

    ter near the lower-left corner. I thought the cloud

    was slightly brighter, so I spot-metered that.

    When using the Zone System, make sure the whole

    spot is filled with a consistent toneyou dont

    want a mixture of light and dark areas. A narrow-

    angle spot meter is invaluable. In this case, I pushed

    my 70200mm zoom out to 200mm and pointed

    the central spot at the brightest part of the cloud.

    At 50 ISO, with my aperture set to f/22 (I used my

    lowest ISO and smallest aperture to make the shut-

    ter speed as slow as possible), the spot-meter read-

    ing from the cloud indicated 1/30 of a second.

    If you remember, back in the beginning of this eBook

    I said that all light meters are calibrated to a middle

    tone, or middle grey. If I took this photo at the meter

    reading (1/30 at f/22) the cloud would look grey, not

    white. This is why spot meters are tricky. You cant

    just point the meter at something and trust your read-

    ing. You have to know whether the spot is pointed at

    a middle tone, or something lighter or darker. In this

    case I metered a highlight, so it shouldnt be zone

    5, a middle toneit should be lighter than that.

    So, with my spot meter still pointed at the cloud, I ad-

    justed the shutter speed until my exposure scale showed

    that the cloud was two stops overexposed: +2 on the

    scale (A). This placed the cloud on zone 7. Zone 8

    would be washed out, so zone 7, two stops lighter than

    a middle tone, was as light as this cloud could get with-

    out losing detail. The resulting shutter speed was 1/8

    of a second, two stops slower (and therefore brighter)

    than the initial meter reading of 1/30 of a second.

    A

    SPOT METERING AND THE ZONE SYSTEMCase Study 9: Unicorn Peak

    39

  • next step was very importantI didnt touch

    anything! Id already set the exposure, so I left the

    shutter speed and aperture alone, zoomed out to

    70mm, re-composed, and took the picture. The

    histogram looked just right, with the brightest pix-

    els near, but not touching, the right edge (B).

    For most photographs you can do exactly the same

    thing: spot-meter the brightest important highlight in

    the scene, then overexpose that area by two stops to

    place it on zone 7. This will push the brightest pixels

    in the image near, but not touching, the right edge

    of the histogram. (Of course you should always check

    the histogram and adjust the exposure if necessary.)

    This procedure might seem complicated, but it

    only took me about five seconds. I just pointed

    my spot meter at the cloud, turned the shut-

    ter speed dial until the exposure scale indicated

    +2, then recomposed and took the picture.

    Sometimes you may not want the brightest impor-

    tant highlight to be at zone 7, or +2 on the exposure

    scale. Zone 6 or 6 1/2 (+1 or +1.5) might be better if

    that highlight has saturated coloursa sunset cloud,

    for example, or maybe yellow autumn leaves.

    One more thing: why didnt I just spot-meter a mid-

    dle tone, like the rocks? That might work, but what if

    the cloud was three or four stops brighter than those

    rocks? Then the cloud would be zone 8 or 9, and washed

    out. By metering the brightest important highlight

    Im going directly to the most vital area of the pho-

    tograph and adjusting that to the desired exposure.

    B

    SPOT METERING AND THE ZONE SYSTEMCase Study 9: Unicorn Peak

    40

  • Case Study 10: Sun Breaking Through Mist, Tuolumne MeadowsHDR AND EXPOSURE BLENDING

  • Every digital camera has a fixed dynamic range. If a

    scenes contrast exceeds that range, then no matter

    how you expose the photograph youll end up with

    black shadows, washed-out highlights, or both.

    That is, unless you combine two or more exposures.

    With HDR, or high-dynamic range photography,

    you can capture several different exposures of the

    same scene, then blend these images together in

    software, retaining both highlight and shadow

    detail even in scenes with extreme contrast.

    These exposures can be combined manually in

    Photoshop, with HDR software like Photomatix Pro

    or Nik HDR Efex, or with other exposure-blending

    software, like my current favourite, LR/Enfuse.

    A tutorial on using these applications is beyond

    the scope of this book. But before you can at-

    tempt to blend exposures in software, you need to

    capture the necessary information in the field.

    HDR AND EXPOSURE BLENDING

    Case Study 10: Sun Breaking Through Mist, Tuolumne Meadows

    A

    42

  • Photographing the sun breaking through morn-

    ing mist in Tuolumne Meadows, in Yosemites high

    country, I could see that the contrast was extreme,

    and I knew the only way to capture this scene was

    to blend several different exposures together.

    I started the way I always do, by finding the right expo-

    sure for the highlights, with the brightest pixels near,

    but not touching, the right edge of the histogram. In

    this case, I figured that blinkies in the sun itself would

    be okay, but I didnt want the clouds next to the sun to

    be overexposed. At f/22, 100 ISO, the best exposure for

    the highlights turned out to be 1/250 of a second (this

    was actually two stops darker than the meter reading).

    But at this setting the shadows looked inky, and there

    was a large spike at the left edge of the histogram, indi-

    cating black, detail-less shadows. I guessed that two more

    exposuresone a stop lighter, another two stops light-

    erwould give me enough shadow detail, and the infor-

    mation I needed to blend these images together later.

    HDR AND EXPOSURE BLENDING

    Case Study 10: Sun Breaking Through Mist, Tuolumne Meadows

    B

    43

  • I could have simply moved my shutter speed dial three clicks

    to the left (to 1/125 of a second) and made a second exposure,

    then turned the dial three more clicks to the left (to 1/60 of

    a second) and made the third exposure. But the clouds were

    moving, and any movement between frames would make it

    difficult to blend the images together later. So I set my camera

    to auto bracket three exposures at one-stop increments. Then

    I moved my shutter-speed dial to the middle exposure, 1/125

    of a second, and fired off three quick imagesclick click click.

    Like most cameras, mine auto brackets on either side of

    the exposure Ive set. So by starting at the middle expo-

    sure of 1/125 of a second, it made another exposure at

    1/250 (perfect for the highlights), then a third at 1/60

    (good for shadow detail)exactly what I wanted.

    The darkest image (1/250) showed the brightest pixels

    near, but not touching, the right edge of the histogram,

    and only small blinkies in the sun itself, but the shad-

    ows, as expected, were black (A page 44). The middle

    exposure showed a spike at the right edge, but nothing

    pushed up against the left edgein other words, it had

    shadow detail, at least theoretically (B previous page).

    HDR AND EXPOSURE BLENDING

    Case Study 10: Sun Breaking Through Mist, Tuolumne Meadows

    C

    44

  • The lightest exposure showed a big spike at the right edge,

    but a nice gap between the darkest pixels and the left edge,

    ensuring that I had noise-free shadows (C previous page). So

    I had one image with good highlight detail, one image with

    good shadow detail, and one in betweenjust what I wanted.

    I blended the three images together with LR/Enfuse, which

    usually creates more natural-looking results than true HDR

    software like Photomatix. Then I applied finishing touches

    in Photoshop (D). This final version has good shadow and

    highlight detail, and renders the scene as I visualized it.

    To recap: when youre trying to capture a series of exposures,

    with the intention of blending them together later, start by

    finding the right exposure for the highlights (with pixels near,

    but not touching, the right edge of the histogram). Then make

    an exposure one stop lighter, then one stop lighter again, and

    so on until you see a gap between the darkest pixels and the

    left edge of the histogram, showing that you have shadow detail.

    If the scene contains clouds or other moving objects, first,

    again, find the right exposure for the highlights. Then set your

    camera to auto bracket three exposures at one-stop intervals.

    Next, move your shutter-speed dial three clicks, to the mid-

    dle exposure of the sequence, and fire off three frames.

    Use a tripod to ensure that the images line up properly. If youre

    using JPEG mode, set the white balance manually; with the

    camera set to automatic white balance the colour could change

    between exposures, making it harder to combine the images

    later. With raw mode, automatic white balance is fine, as you

    can sync the colour temperature between the images in software.

    HDR AND EXPOSURE BLENDING

    Case Study 10: Sun Breaking Through Mist, Tuolumne Meadows

    D

    45

  • Conclusion:TECHNIQUE AND VISION

  • I hope the preceding pages have helped you gain a better

    understanding of exposure and the fundamental photo-

    graphic toolsshutter speed and aperture. But getting good

    exposures is not an end in itself, but rather a means to an

    enda way of helping you make better photographs.

    What defines a good photograph for one person might

    be different than for another. We could talk about light,

    composition, or technical proficiency, but I think that if we

    dig down, what most of us are trying to do is communicate

    something about the place or subject were photographing.

    Were trying to capture a mood or a feelingto express

    ourselves in some way, and evoke a reaction in the viewer.

    Exposure, then, is just a tool for communication.

    Theres no such thing as a correct exposure for any

    situation. If the exposure helps you say what youre try-

    ing to say, then its correct enough. If it detracts from

    your message, then it isnt correctat least for you,

    in that instance. Exposure must always serve your vi-

    sionnot someone elses, nor some arbitrary ideal.

    These last four photographs deviate from the accepted

    standards for proper exposure and sharp detail. Instead,

    I made choices that, to me, conveyed a feeling or mood

    that fit the subject. A lighter exposure communicates a

    different mood than a darker one. Sharpness conveys

    a different feeling than deliberate blurring. So use your

    tools well. Rather than striving for technical perfec-

    tion, use technique to make more expressive images.

    Conclusion:TECHNIQUE AND VISION

    (Left) To capture the soft, delicate quality of this iris, I overexposed the image slightly, and used a wide-open

    aperture to throw most of the flower out of focus and create washes of colour.

    (Previous page) Here I went in the other direction and deliberately underexposed this photograph of Half Dome,

    creating large areas of pure black, and enhancing the stormy mood.

    47

  • This photograph of a Jeffrey pine was deliberately and drastically overexposed to let the highlights wash out to create a delicate, high-key look.48

  • To convey the beauty and coordinated motion of these snow geese, I used a slow shutter speed (1/15th of a second) while panning as they took flight.49

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