Digital Camera Magazine - Master Exposure

8/14/2019 Digital Camera Magazine - Master Exposure

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How to read a histogram

Metering for different tones Coping with unusual lighting

TAKE STUNNING PHOTOSUSING OUR EXPERT TIPS

ExposureMaster

Complete photography guide

VITALSKILLSGUIDE


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Exposure 3

Exposure

Master

Trying to get the correct exposure is one of the

greatest challenges for those beginning in

photography. But it neednt be. This book will

show you the pitfalls to avoid, when to alter

your cameras settings (and by how much) and

how to get creative with metering.


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MasterExposureTAKE STUNNING PHOTOSUSING OUR EXPERT TIPS


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6/48Exposure 7

Exposure basics p10

Adjusting exposure p14

When things get tricky p16

Master of exposure: Ansel Adams p20

Background problems p22

Unusual lighting p26

Master of exposure: Galen Rowell p30

How to read a histogram p32

Controlling the dynamic range p36

Using a neutral density grad p38

Master of exposure: Pl Hermansen p42

Low light exposures p44

High key/low key p46

Top 10 tips p49

Contents


7/488 Exposure

The biggest advantage digital has over film is thefact that you can check your shot once youvetaken it. You can bring up a histogram to check the

brightness range of a scene and make sure youre not

underexposing or overexposing it. You can, if your

camera allows, switch on a flashing highlight to show

you any blown highlights where detail will be lost in

your photograph. You can then change your exposure

accordingly. And if all that fails to produce the balanced

exposure you want, you can go some way to rectifying

it while image-editing.

It is, however good to get things right first time to

produce a high-quality image in-camera which you

only have to do minimal tweaking with later. This book

arms you with practical advice for getting the

exposures you want, and the confidence to take

control when the cameras being fooled. Weve gotclear examples of when this can happen and what you

should do. We also show you the inspiring work of

three master photographers to give you an idea of you

what can be achieved once youve nailed the basics

which start on page 10

Marcus HawkinsEditor, Digital Camera Magazine

Use your grey matter


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10 Exposure

On the face of it, exposure seems a prettystraightforward business. In order toproduce a good range of tones in your picture,

the camera has to make sure the right amount

of light reaches the sensor. And it does this (or

you do) by adjusting the length of the exposure

(the shutter speed) and the light intensity (the

lens aperture). The image is formed by the

accumulation of light on the sensor during the

exposure. All digital cameras incorporate

exposure systems which will do this

automatically, so whats the problem? Even themost sophisticated metering system is unable

to understand what the cameras looking at, or

what the photographers intentions might be.

This is where you need to take control.

Exposure

basics


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Exposure 11

Digitals dynamic rangeCameras will struggle to deal with scenes where

theres an extreme brightness range. With film,

this is called exposure latitude, with digitalcameras its called dynamic range. On a very

bright sunny day, it may be impossible to find an

exposure which records some detail in the

shadows without blowing out the highlights, or

vice versa. Its generally agreed that digital

cameras have a similar exposure latitude to slide

film, and you can start off by assuming a

dynamic range of about 4 EV values. This meansyou should still be able to see or recover useful

shadow detail 2 EV darker than the mid-tones

in your image, and highlights 2 EV brighter than

this mid-tone value should record well too. So

what do you do if the brightness range in the

scene exceeds this 4 EV range? There are ways

of dealing with this, and we look at these a

little later on.

Mid-tonesThe idea of mid-tones is important in exposure.

On one level, it describes areas of the scene

which are more or less in the middle of the tonalrange. You might say these are the parts you

want to expose correctly. But how dark or light

are these mid-tones? In order to work out the

exposure, your camera has to work to a

standardised average grey tone 18% grey, to

be precise and try to adjust the exposure to

reproduce your subject with this level of

brightness. This is one of the principle drawbacksof all built-in camera meters, no matter how

sophisticated. They dont know what it is theyre

looking at, and what intrinsic tone the subject

ought to have. All subjects will be reproduced to

this 18% grey value, which is a problem well

come on to shortly.

At first glance, this scene seems to averageout an overall mid-tone. However, the

bright wall of the cottage is overexposed. Diallingin some underexposure would take the edge off

this, at the expense of detail in the shadows.


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12 Exposure

Metering patternsLight meters may not be able to understand that

different subjects may have different intrinsic

brightness levels, but camera makers have at least

been able to allow for difficult and contrasty

lighting conditions. By default, digital cameras

use multi-pattern metering systems that

measure the light values at numerous points in

the scene. This helps them build up a picture of

the type of lighting youre shooting in, and the

camera may adapt automatically to backlighting,for example. Multi-pattern metering systems are

hard to second-guess, though, and many

photographers prefer simpler centre-weighted

metering, which averages the whole scene but

places extra emphasis on the central area. Spot

metering is very specialised. It takes a reading

from a very small area of the scene only.

Aperture and shutter speedDigital cameras control exposure using both

shutter speed and aperture. Why both? Wouldnt

one or the other do the job? There are creative

advantages to these two means of exposure

control. Smaller lens apertures offer more depth

of field (near-to-far sharpness), while fast shutter

speeds let you freeze fast-moving objects.

Shutter speed and aperture are interchangeable,

so that if you want to use a smaller lens aperture,

you can compensate with a longer exposure. Or,if you want a shorter exposure, you simply set a

wider lens aperture. For example, if your camera

indicates an exposure of 1/250sec at f/8 but you

want to shoot at 1/1000sec, which is two stops,

or EV values, faster, you need to increase the

aperture value by two stops as well, to f/4. Some

cameras allow you to adjust shutter speed and

aperture values in 0.3 EV steps, but the sameprinciple applies a change in one must be

mirrored with a same-sized change in the other.

To blur the crashing waves inthis scene, a smaller lens aperture

has been selected in order to obtain

a slow shutter speed.

When faced by a mid-tone scenesuch as this, multi-pattern metering

systems can be trusted to produce well-exposed photographs.


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Exposure 13


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14 Exposure

So how precise do you have to be withexposure? Even though digital cameras onlyhave a certain amount of exposure latitude, in

practice there are many different ways ofinterpreting a scene, and many exposure errors

can be rectified or at least improved with a bit of

image-editing. To give you an idea of how the

subject brightness changes with exposure, heres

the same scene at seven different exposure

values, all shot at the same lens aperture, but

with shutter speeds 0.5 EV apart. These also

demonstrate the idea of exposure latitude anddynamic range. There isnt one shot where

details been recorded both in the foreground

and the garden outside the scene is outside the

dynamic range of the cameras sensor. You might

prefer the overexposed shot because it shows

the subjects face with a nice high-key effect, or

a darker silhouetted version. Or you might open

one of the in-between shots in Photoshop andattempt to balance the tones more evenly.

Adjusting

exposure

The shot with the biggest increase inexposure works well it bleaches

out a potentially distracting background.

+1.5 EV


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Exposure 15

+1 EV +0.5 EV 0 EV

-0.5 EV -1 EV -1.5 EV


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16 Exposure

The black background and dark subjectfooled our cameras meter. Left to its

own devices, it overexposed by 2 EV.

We explained in the previoussection that camera exposuresystems could adapt to a degree to

difficult lighting, but that they had nosense of the intrinsic lightness or

darkness of specific subjects. But does

this really make much difference? Indeed

it does. If any of your digital camera

shots come out badly exposed, its often

the intrinsic brightness of the subject

thats caused the problem, not difficult

lighting or any error on your part.Just to show you how much

difference intrinsic subject brightness

does make, weve arranged a series of

still-life experiments

When things

get trickyMetering for dark tones/blackWe used a black background for this shot

of an ornamental elephant, which itself

was a mixture of dark red and black. Thecamera didnt know any of this, of course.

All it could do was measure the amount of

light it saw. Not surprisingly, this wasnt

very much! As a result, the camera

increased the exposure. Remember, all it

can do is attempt to render the subject as

an overall 18% grey tone, because while

you and I might realise the elephant andthe background is black, the camera

doesnt have the cognitive powers of the

human brain. Its dark, increase the

exposure. Thats the limit of its thinking.

The result isnt too hard to predict; an

18% grey elephant against an 18%

grey background.

No Adjustment


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Exposure 17

Watch out for highlightsOur elephant shot reveals something else

thats interesting, too. In the overexposed

version, look at the dried flowers in theforeground. Theyre actually close to an

average 18% grey tone in real life, but

because the cameras increased the

exposure, theyve been almost completely

burned out. However, by manually

overriding the exposure and reducing it by

2 EV, weve not only restored the elephant

and the background to a proper black,weve restored the correct tones to the

dried flowers. The same will apply if youre

photographing black birds with bright

beaks, for example. When youre

photographing dark-toned subjects, the

camera will often increase the exposure

and lose highlight detail in other parts of

the scene. The subjects darkness doesnthave to be as extreme as that in our

example. If youre shooting dark-toned

vegetation, for example, reducing the

exposure by 0.7 EV to 1 EV is often a good

idea to preserve the depth of colour and

highlight detail.

-2 EV


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18 Exposure

Metering for light tonesUnusually dark-toned subjects are not an

everyday problem. Light-toned subjects are

far more common, and they typically distort

the cameras meter reading to a greater

degree. Our still life shot demonstrates this

well. The ginger, onions and squash are all

fairly light-toned, along with the cloth

beneath them, but even so you might expect

the camera to expose them correctly without

any help. The result, though, is distinctly dull

and gloomy. Only by reshooting with

+0.3 EV compensation were we able to

restore a realistic-looking brightness to the

shot. At first you might need to experiment a

great deal to find appropriate EV

compensation values for light or dark-toned

subjects. But with practice, and a growing

understanding of your cameras behaviour, it

gets a lot easier to work out when to override

the camera and how much by.

These vegetables are lighter-toned than the

average 18% grey looked for by the cameras

meter, so we needed to apply EV compensationto make sure this is how they were reproduced.

No Adjustment +0.3 EV


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Exposure 19

Metering for whiteWhite subjects are a special case, and the

cause of the most severe underexposure

problems. Theyre a special case because the

world is full of white objects and

backgrounds, and because you might be

surprised at just how bright they are. This still

life demonstrates this very well. Remember,

we want objects to appear in photos as they

do in real life, and not reduced to the 18%

grey assumed by camera meters. Our first

attempt, shot using the cameras default

exposure reading, was a disaster. Indeed, the

overall tones are very similar to those of the

default black elephant shot, demonstrating

how the camera attempts to reduce all tones

to the same value. In order to reproduce the

whiteness of our subject, we had to increase

the exposure value by 2 EV. Youll have to do

the same with snow scenes, for example, or

close-ups of wedding dresses.

If youre photographing anything white, beware! Yourcameras meter will attempt to reproduce it as a muddy

grey, so you need to intervene. This shot required +2

EV exposure compensation to look right.

No Adjustment +2 EV


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20 Exposure

T here cant be many people whove never seen anAnsel Adams photograph. He is the acknowledgedmaster of landscape photography. He achieved so

much before his death in 1984 of heart failure at the

age of 82. Adams was both a photographer andconservationist and started the f/64 group (an

association of Californian photographers who

promoted pure photography) with Edward Weston in

1932. Hes perhaps better known for developing the

zone system for exposure, a technique which enabled

him to visualise how he would print the various parts

of the image, and expose the negative accordingly. The

tonal range he managed to extract from his black andwhite film was simply incredible.

Master of

exposureAnsel Adams

20 Exposure


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Exposure 21

This is unmistakably an Ansel

Adams landscape. The

richness, depth and detail is

astounding, the exposure capturing

every nuance of light. It pictures the

Tetons and Snake River in Grand Teton

National Park, Wyoming, and was shotin 1942.

To learn more about AnselAdams, pay a visit to

anseladams.com.

Exposure 21

Corbis


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22 Exposure

You may not encountercompletely black

backgrounds like this when

youre out shooting, but darktones will have the same effect.

I ts not necessarily the subject of yourphotograph that can give you exposureheadaches. The tone of the background is just

as important, and can have a big influence on

the exposure reading. Even if your subject

consists of fairly even mid-tones, an unusually

light or dark-toned background can produceexposure errors. The size of this error will

depend on how much of the frame is taken up

by the background. It can also be hard to

judge exactly how much emphasis the camera

is giving to the subject itself, since multi-

pattern metering systems may concentrate on

the object in the middle of the frame, which

may or may not be where your subject is.

Size mattersThis shot uses a mid-tone subject set against a

dark background, but shot at two different

zoom settings, so that in one the onions and

ginger take up nearly all of the frame, while in

the other theyre quite small relative to the

background. In both cases the cameras

default auto-exposure readings were used.

The close-up shot is correctly exposed, but in

the zoomed-out version, the larger proportion

of dark background has fooled the camerainto overexposing by 1.3 EV.

We tried the same experiment using a light

background. By zooming right in on the

Background problems

Light backgrounds causemid-toned subjects to

underexpose if theyre not big in

the frame. Bear this in mind whenframing people against pale skies.


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Exposure 23

artificial fruit, weve excluded nearly all of the

background, and the resulting exposure is pretty

well spot-on. When we zoomed out, though, the

proportion of the frame taken up by the

background was far higher, leading the camera to

reduce the exposure by 1.3 EV, which has left the

shot underexposed. The degree to which thebackground influences exposure will depend on

the amount of the frame it takes up and its

brightness, but it can make a big difference.


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Complimentary tonesHeres another experiment showing how the

exposure changes when you place a darksubject against a light background. In this

case the best exposure is the middle one,

because the light background has reduced

the exposure. This helps render the dark

tones of the lenses more accurately.

You can also see what happens when you

place a light subject against a dark

background. The results are similar. Close-up,the while flowers and vase in our set-up

cause the camera to underexpose. In the

wideangle shot, the dark background has

caused overexposure. The middle shot is the

best because the tones average out well.

24 Exposure


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Exposure 25


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26 Exposure

Just to make life that little bit more awkward,its often the most dramatic and difficultlighting that makes the most exciting

photographs. You face two challenges here. The

first is that the brightness range of the lightingwill often exceed the dynamic range of your

cameras sensor, so you have to decide which is

the most important part of the scene and base

the exposure on that, leaving extreme highlight

or shadow detail to disappear. Once youve done

that, you need to work out how to take an

exposure reading that will render the important

part of the scene properly.

Unusual

lighting

Backlit images can be some of the

most exciting, but they also provideplenty of exposure headaches. Mostcompact digital cameras will favour

shadowed foreground subjects, like ourpedestrians, and this compromise has

worked out well here.


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Exposure 27

Backlit subjectsWith backlit subjects, the lights coming from

behind your subject and towards the camera.

This means that the side of the subject facing you

is in shadow against a bright background. Itsunlikely that your camera will be able to record

detail in the subject and a full range of tones in

the bright background too, so youve got a

decision to make. You can expose the shot to get

detail in your subject, and render the background

as a brilliant, ethereal white, or go for a silhouette

effect, as you might with a dramatic sunset, for

example. In both cases, spot metering can be themost reliable solution because multi-pattern

metering systems can behave a little

unpredictably. Some are designed to give priority

to subjects in the centre of the frame, especially

with the tonal distribution characteristic of

backlighting (the camera can detect this). You

may get a properly exposed subject when you

wanted a silhouette, and vice versa.


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28 Exposure

Sidelit subjectsSidelighting is less difficult to deal with. The

overall contrast tends to be lower because youre

not shooting into the light. However, the long

shadows cast by the light can influence the meter

in ways you dont want. Digital cameras,

especially non-SLR models, seem to favour

shadows over highlights in a scene, so you canoften end up with an overexposed image with

blown highlights and shadow detail thats too

light. The strong, textural quality of sidelighting,

however, relies heavily on deep shadows and

richly-coloured highlights. Its a good idea with

sidelit subjects to at least bracket your exposures,

or take one at the default meter reading and then

another with -0.3 EV or -0.6 EV compensation.With digital cameras, a little underexposure is a

lot easier to correct later than overexposure.

Blown highlights are lost for good, but you can

often extract an amazing amount of colour and

detail from gloomy shadows.

If you want to capture the fullrichness of colour and textural

quality of sidelit subjects, you may have

to manually reduce the exposure to retainthose dark shadows.


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Exposure 29

Spotlit subjectsSpotlit subjects are particularly difficult to deal

with. The situation here is comparable to that we

set up when photographing subjects against a

dark background, but the contrast in tones is

going to be even higher. Left to its own devices,

the camera will attempt to compensate for the

darkness of the background, leaving your mainsubject hopelessly overexposed. The solution

here is to take a spot reading from the area being

spotlit. In addition, youll have to make

allowances for the intrinsic brightness of your

subject, which is one of the reasons why spot

metering is quite a skill. For example, if youre

photographing a performer on stage in a white

costume, you might need to take a spot readingfrom the costume, then dial in +2 EV exposure

compensation to make sure it reproduces as

white. Landscapes spotlit by the sun breaking

through clouds are generally easier to meter for,

thanks to their more mid-toned nature.

Spotlit subjects are one of thetrickiest to expose for, but spot

metering can help you out. Be careful of

metering from intrinsically light or dark-toned objects, though.


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The world lost of one its greatest wildernessphotographers on August 11th 2002, when GalenRowell and his wife Barbara died in a plane crash in

California while returning from a photo workshop in

the Arctic. He was 61. Rowell was a perfectionist whenit came to his photographs. His search for the dynamic

landscape meant seeking out the best light and having

the confidence to control it. Such was his mastery of

exposure, he had his own branded range of graduated

neutral density filters, developed by Singh-Ray.

Rowell started out as a car mechanic, but gradually

began to fuse his passions of mountain climbing and

photography into a successful career. In 1972 he

received his first commission from National Geographic

to capture an ascent up Yosemites Half Dome

monolith. The photographs he brought back proved so

powerful that one was selected as the cover shot.

He went on to shoot numerous stories for the

magazine and publish an impressive series of books,

including the legendary Mountain Light the name

he went on to use for his photography business and

My Tibet, co-written with the Dalai Lama. He

received the Ansel Adams Award in 1984, for his

contributions to the art of wilderness photography.

Master of

exposureGalen Rowell

30 Exposure

While Galen Rowell rose to


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prominence with his

staggering images of

mountains, he was a master craftsman

of landscape and wildlife photography

as well. This shot of sunflowers taken in

the eastern Sierra, California, in 2000shows how skilled he was at reading

light. The strong backlight and delicate

form of the flowers have been captured

with perfection. The use of a graduated

filter has tamed the harshness of the

top part of the frame, making the

dynamic range of the scene more

manageable. The resulting imagetakes your breath away.

See more of Galen Rowells

awe-inspiring work atwww.mountainlight.com.

Exposure 31


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32 Exposure

So far weve been basing our assessments ofexposure levels on the appearance of imageson a screen or in print. Theres a more technical

way of assessing the tonal balance of digital

images, though, and thats using a histogram.Many cameras can display live histograms as

you compose a shot and/or histograms for saved

images. You can display a histogram in

Photoshop and other image-editors, too.

The histogram will tell you whether you have

blown highlights, blocked-in shadow detail,

whether theres a full range of tones, and how

light or dark the image is overall. Its basically a

bar chart (though with so many bars they

blend into a continuous curve) showing how

many pixels there are for each brightness value

across the tonal scale, from dense black to

brilliant white.

The perfect spread of tonesYou may hear people talk about the ideal

histogram, but in practice histograms can come

in many different shapes, depending on the tonal

balance in the image. What you would want to

see in a histogram, though, is the histogram

curve tailing off to zero more or less exactly at

the far left-hand (shadow) end of the scale and

again at the far right (highlight) end. Thats

exactly what weve got with our sample shot

here. However, if the histogram is chopped off atthe left, that means there are areas of solid black,

How to read

a histogram

or blocked-in, detail-free shadows in the image. If

the histogram is chopped off at the right, youve

got blown highlights, which are areas of

featureless white. If the histograms been chopped

off, or clipped at either end, theres nothing youcan do to bring that image detail back.


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Exposure 33

Un s al histogram shapes


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34 Exposure

The typical histogram tails off at the left and

right-hand ends, but swells to a maximum

somewhere round the middle. Some subjects,

though, produce very different results. If youshoot a shadowed subject against a bright sky,

you might get two peaks, one in the shadows,

one in the highlights,

and practically nothing

in the middle. Theres

nothing wrong with

your exposure

technique, its justcharacteristic of this

type of subject.

On overcast days, or in other situations where

theres not a lot of contrast, you might end up

with a histogram that tails off to zero long before

the left and right-hand ends of the scale. This is a

characteristic of flat-looking images. As the

histogram shows, there are no really dark or

really light areas,

which is a problem

because photographs

usually rely on a full

range of tones for

depth and richness.

Unusual histogram shapes

Flat histograms

Clipped shadows


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Exposure 35

Histograms can reveal obvious flaws in your

images. This shot has been underexposed, and

this has moved the whole histogram to the left,

with the result that the shadows have been badlyclipped, while there are no real bright highlights

(the histogram doesnt reach the right-hand end

of the scale). You

can adjust the image

in Photoshop to

restore brilliant

white highlights,

but you cant doanything about

those lost shadows.

This image has the opposite problem. Its been

overexposed, with the result that the whole

image histogram has effectively been moved to

the right. Even though weve recorded the

shadow detail nicely, the highlight end of the

histogram has been

clipped, just as the

histogram curve is

rising, indicating the

presence of lots of

bright tones in the

sky. These tones cant

be recovered.

Clipped shadows

Clipped highlights

C lli h d i


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E arlier, we mentioned the idea of dynamic range therange of tones your digital cameras sensor can record. Thisties in with our look at histograms in the previous section. You

can think of your cameras dynamic range as an exposure

window. Your job is to try to get the full range of tones in your

subject into this window. As weve seen, if the brightness range

is too high, you have to decide whether to sacrifice extreme

highlight or shadow detail, depending on what you consider tobe the main subject. This isnt the only alternative, though.

There are things you can do to reduce the contrast range in the

scene at the time of shooting.

Controlling the dynamic range

Fill flash is a useful way ofbalancing extremely high contrast

scenes, but it only works on subjects

within the range of the flash, typically 2-4 metres for a built-in flash.

36 Exposure

Before


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Exposure 37

Using balanced fill flashOutdoor portraits are often difficult to pull off

successfully, especially in bright sunlight. If you

face your subject towards the sun you reduce the

contrast range but you make them squint. If you

position them side-one, you get ugly shadows

across their face. And if you shoot them with their

back to the light, you have the problem that theirface is in shadow against a bright background.

However, if you set your cameras flash to forced

flash mode, and as long as your subjects just a

metre or so away, it can provide enough fill light

to even up the tones. You can use fill flash

indoors, too, as we have here, to balance up dim

indoor lighting against bright daylight outside. If

your camera has a slow sync mode, you can

create interesting flash effects at dusk, too,

illuminating nearby objects against a colourful

sunset or twilit sky.

After


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38 Exposure

Using a neutral density gradLandscape photographers often struggle with bright

skies, particularly on overcast days, where the skyacts, in a sense, as a vast, diffused light source and

one which is 2 EV to 3 EV brighter than the

foreground. You have a dilemma. Either you expose

for the foreground and risk the sky bleaching out to a

featureless white, or you expose for the sky and hope

you can drag up enough detail from the dark

foreground in your image-editor. If the brightness

range is too great (it often is), you need anothersolution. For this shot, weve used a neutral density

grad, a filter which is darker at the top than the

bottom. By positioning this carefully in the filter

holder, weve darkened the sky enough to even up the

exposure, but without affecting the foreground.

Graduated neutral density filters come in various

strengths, which you can match to the brightness

range of the scene. Its largely a matter of personal

taste though do you like the heavily filtered moody

look, or something more natural? They also come in

both soft-edged and hard-edged forms. The soft-

edged sort can intrude intro areas of the frame you

dont want to reduce in brightness (the top of a hill

thats protruding into the sky, say), but the hard-

edged ones demand even more careful positioning.

To get the most from a neutral density grad, you

really need a digital SLR, though filter maker Cokindoes supply an adaptor kit for digital compacts.

A graduated neutral density filter solvesthe problem we had with clipped highlights

in our landscape shot. It reduces the exposure

in the sky area by a factor of 4 (2 EV) to bringit within the sensors dynamic range.

Without Filter


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Exposure 39

With Filter


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Using PhotoshopPhotoshop CS and Elements 3 have a Shadow/Highlight tool

for balancing the tonal values in high-contrast scenes. It worksby selecting the darker areas only and then lightening them.

The results can look a little artificial if youre not careful (you

need a large Radius setting, which blends the effect more

subtly), but they can also improve shots considerably. This will

only work, though, if the image contains a full range of tones in

the first place. If the shadow or highlight detail has been

clipped, theres no getting it back. For scenes with too high a

contrast range for this approach, there is an alternative. You

can take two shots at two very different exposure values one

aimed at capturing shadow detail, and one aimed at capturing

highlight detail then blend them in Photoshop. Our

walkthrough shows you one way of doing this. (Youll need to

use a tripod to ensure the images align exactly.)

40 Exposure

We needed to reduce theexposure by a massive 6 EV inour second shot, the onebeing used to record the dusk

sky in this beach scene. Theblended image records a

dynamic range impossible tocapture in any other way.

Before

After


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Composition 41

1Combine the shotsThe first thing to do is add the lighter

exposure to the darker one as a new layer. Youcan do this by using the Move tool to drag it onto the other images window. If you hold down

the Shift key as you do it, the image will alignautomatically.

2Blend the exposuresNow use the Colour Range command and

select Highlights from the pop-up menu. Youllneed to make sure the Invert box is checked.Close the dialog box, and click the Add Layer

Mask button in the Layers palette. This willmask the bleached-out areas in the top layer.

3Blur the transitionThe transition between the two image

layers is too abrupt at the moment, but the wayto fix that is to blur the layer mask. Making surethe mask is selected in the Layers palette, try a

Gaussian Blur of 250 pixels (less for lower-resolution images).

Master of


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L ike many great photographers of the naturalworld, Pl Hermansen started his working lifedoing something else. Born in 1955 in Oslo, Norway,

he trained as a dentist and homeopath, but was an

enthusiastic photographer from an early age. He

decided to turn his hobby into a career in 1971, when

he became a freelance photographer and writer.

As well producing numerous books, his striking work

has earned him international acclaim and many

awards. His images stand out from the norm because

of their exquisite portrayal of light and creative

compositions. He attempts to go beyond documentary

-style photographs to create something more artistic,

admitting that he perhaps leans more toward the

photographic equivalent of poetry.

Master of

exposurePl Hermansen

42 Exposure

This shot of black-legged

kittiwakes, taken on Norways

Lofoten Islands proves that


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Lofoten Islands, proves that

sometimes, searching for the perfect

exposure isnt always desirable. Would

this picture have as much impact if it

had a more neutral composition andexposure? Notice how the soft edges of

the bird thats out of focus work in

combination with its overexposed white

feathers to make it almost glow. Its an

image that provokes extreme reactions

youll either love it or hate it.

Intrigued by Pls work? See

more in the galleries atpalhermansen.com.

Exposure 43

Low light exposures


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S hooting at night is easy, it just needs muchlonger exposures than youre used to in thedaytime. You could increase your cameras ISO to

its maximum and try shooting handheld, but the

image quality will drop through the floor, and

shutter speeds will still be so long that camera shake

is nigh-on inevitable. The best approach is to use a

tripod, reduce the ISO to its minimum (to maximise

image quality) and experiment. Yes, experiment.

While your camera is perfectly happy with the

long exposures needed at night, its metering

system is likely to be all at sea when faced with

the naked light sources and much higher contrast

levels after dark.

Exposing in the darkThere are two approaches to working out exposures

at night. Theres the it ought to be possible to work

this out approach, and the I give up, lets just suck

it and see approach. The technical approach would

be to take a spot reading from a representative area

of the scene like a floodlit building, but excluding

any naked light sources. This is time-consuming and

error-prone. The simplest route is to start with an

exposure of 4 seconds at f/5.6 for a typical cityscene, see how it comes out, then reshoot with

different settings. There is one thing to beware of,

though. Your cameras LCD will appear much

brighter at night, so that while an image may look

good when played back at the time, it can prove to

be hopelessly underexposed when you get it on to

your computer. Instead, use your cameras

histogram display to check the tonal distribution this is a much better guide.

Low light exposures

44 Exposure


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How to control noiseNoise can be more of a problem with night shots,

and there are reasons for this. First, if you dont

manually set your camera to a low ISO, it will

automatically increase the sensitivity in response

to the lower light levels. Auto ISO is a default

option with compact cameras especially. Second,

long exposures tend to encourage more sensor

noise. However, makers now incorporate

effective noise-reduction systems that kick in

automatically with longer exposures. Check

whether your camera does this, or whether you

have to enable noise reduction manually. Third,

noise tends to be more apparent in darker areas,

and night shots can contain large expanses of

black or dark tones. You can reduce noise inPhotoshop and other image-editors, but only at

the cost of some fine image detail. The Dust &

Scratches filter is probably the most usable and

controllable tool for this.

Night photography presents special

exposure challenges. Often a purelyexperimental approach is the quickest andbest solution.

Exposure 45

High key/low key


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46 Exposure

T he concept of the ideal histogram can beuseful when choosing exposure settings andevaluating images, but its a mistake to imagine that

all images must conform to this even distribution of

tones. Intrinsically light subjects, for example, can

be expected to produce histograms where the tones

are clustered up around the right-hand (highlight)

end of the scale, whereas dark subjects should

produce histograms shifted towards the darker, left

end. This is exactly how these subjects should look.

Deliberately light images are called high key

photos, while dark shots are low key.

High key/low key

High key


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Exposure 47

Going to extremesYou can take high key and low key exposures to

extremes, and produce striking and creative

results. For example, if you place a fair-skinned

model against a bright background, and use an

exposure which just captures the details of the

face at the highlight end of your cameras

dynamic range, the result will have a brilliant,

ethereal quality. Or, to produce a far more

sombre, dramatic portrait, you need to choose a

dark background, contrasty lighting, and set an

exposure that records the highlights on the

subjects face but the shadowed side and the

background as very dark, near-black tones.

The histograms for these images will be very

far from the ideal shape, and may also haveclipped highlight or shadow detail.

Nevertheless, they can work very well as

photographs. The point about histograms is

that they simply tell you what the image is like

theyre a diagnostic tool. Theyre not there to tell

you what the image ought to be like. Thats your

job as the photographer.

You can do effective high key and

low key portraits using either naturalor artificial light.

Low key


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Exposure 49

1TAKE A MID-TONE WITH YOUPack a grey card in your camerabag or buy a mid-toned camerabag which you can meter off.

2LOOK AT THE HISTOGRAMDont rely on a simple playbackimage to judge exposure let thecamera show you precisely

3WATCH THE BACKGROUNDBe aware of how the tone of abackground can influence yourcameras meter.

4BE AWARE OF HIGHLIGHTSWhen exposing for dark subjects,look for any bright areas thatmight be blown out as a result.5SWITCH TO SPOT METERINGFor tricky lighting and small areas,theres no substitute for spotmetering if youre not in a rush.

6RESTORE THE WHITENESSIf your subjects large in the frameand bright white, spot meter offthem and add 2 EV to 2.5 EV.

7METER FOR HIGHLIGHTSAs a general rule, its best to meterfor the highlights and let theshadows fall where they will.

8CARRY A SET OF FILTERSAlways pack a graduated neutraldensity filter and polariser theyrenot just useful for pure landscapes

9DIAL DOWN YOUR FILL FLASHWith digital cameras so good atpicking up shadow detail, youll besurprised how little fill flash you need.10 GET CREATIVEDont always chase theperfect exposure.Experiment with going to extremes.

ExposureMasterTop 10 tips...

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Digital Camera Magazine - Master Exposure