Black + White Photography - Special Issue - Digital Exposure Handbook

Digital ExposureHANDBOOK
ROSS HODDINOTT
Revisededition
SPE
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Digital Exposure HANDBOOKRevised edition
ROSS HODDINOTT

First published 2008 This edition published 2013 byAmmonite Pressan imprint of AE Publications Ltd166 High Street, Lewes, East Sussex, BN7 1XU, United Kingdom
Text and photographs Ross Hoddinott, 2013 Copyright in the Work AE Publications Ltd, 2013
All rights reserved
The right of Ross Hoddinott to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988, sections 77 and 78.
No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means without the prior permission of the publisher and copyright owner.
This book is sold subject to the condition that all designs are copyright and are not for commercial reproduction without the permission of the designer and copyright owner.
The publishers and author can accept no legal responsibility for any consequences arising from the application of information, advice or instructions given in this publication.
A catalogue record for this book is available from the British Library.
Publisher: Jonathan BaileyProduction Manager: Jim BulleyManaging Editor: Gerrie PurcellSenior Project Editor: Dominique PageEditor: Rob YarhamManaging Art Editor: Gilda PacittiDesigner: Chlo Alexander
Set in Bliss
Colour origination by GMC Reprographics
Picture credits
All photographs by Ross Hoddinott, except for the following:
2020VISION/Ross Hoddinott: 77, 98, 173, 179Ollie Blayney: 87, 88Tom Collier: 64 (top)
Additional images by: Canon 24, 129; Datacolor 182; Epson 185 (top); Hoya 151 (far right), 160; Lastolite 121, 144; Lee Filters 151, 155, 158; Lexar 168; Nikon 66, 67, 126, 130, 132; Permajet 184/185; Sekonic 17; Wimberley 145.

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Contents
Introduction 8
The basics of exposure 13
Exposure in practice 71
Ambient light 103
Flash light 123
Filters 147
Exposure in the digital darkroom 165
Glossary 188
Useful websites 190
Index 191

8Introduction
exposure / noun.The act, or an instance, of exposing a sensitized photographic material, or the product of the light intensity multiplied by the duration of such an exposure.
Exposure is the heartbeat of photography. Put simply,
it is the process of light striking a photosensitive
material, such as lm, photographic paper or a digital
cameras image sensor. Understanding and being
able to control exposure is critical to successful
photography. However, it is a subject that, at times,
can appear complex and confusing not only to
beginners, but enthusiasts as well. So many things
can in uence exposure, including the time of day,
focal length of the lens, subject movement, light
source and any lters attached. Certainly, when I rst
began taking photography seriously as a teenager,
I found the theory and technicalities of exposure
tricky to understand. However, I quickly realized that
if you try to overlook this key fundamental, your
photography will suffer and never realize its full,
creative potential.
Exposure is a combination of the length of
time and the level of illumination received by
a light-sensitive material. This is determined by
three settings: shutter speed, lens aperture and ISO
equivalency rating. The shutter speed is the duration
of time that the cameras shutter remains open,
allowing light to enter and expose the sensor. The
aperture or f-stop is the size of the adjustable
lens diaphragm, which dictates the amount of light
entering the camera. The ISO speed indicates the
sensors sensitivity to light. At lower sensitivities,
the sensor requires a longer exposure to get a good
result, while at high sensitivities, less light is needed.
If the combination of shutter time, aperture
and ISO sensitivity is incorrect, the picture will be
wrongly exposed. Too much light falling on the
sensor will result in an overexposed image with
washed out highlights; too little light and the
image will be underexposed, appearing too dark.
Simply speaking, a good photograph relies on the
photographer employing just the right combination
of settings to form the correct level of exposure.
However, while this might be logical in theory,
I often ask myself: Is there really such a thing as
the correct exposure? While you could say that
a correctly exposed image is one that records
the scene or subject exactly as our eyes see it,
photography is a subjective and creative art. There
is no rule stating that a photographer must always
capture images that are authentic it is subject
to individual interpretation. Therefore, arguably,
a correct exposure is simply one that is faithful
to the vision of the photographer at the moment
he or she triggers the shutter.
Todays breed of digital cameras boasts highly
sophisticated and accurate internal metering
systems, which are rarely fooled even in awkward
lighting conditions. They have simpli ed many
of the technical aspects of exposure, for which
we should be grateful. However, a camera is still
only a machine; it cannot predict the effect and
look the photographer is striving to achieve. It is
for this reason that you shouldnt always rely on
your cameras automated settings. Remember:
you are the artist and, as such, you need to grasp
control from your camera. Fail to do so, and your
images will never truly convey your own individual
interpretation of the subject you are shooting.
XDamsel yEvery time you take a photo, you are recording
a unique moment that can never be repeated.
A good understanding of exposure is vital to
ensure your image is compelling to others and
faithfully captures the light, essence and mood
of that particular moment.
Nikon D800, 150mm, ISO 200, 1/3sec at f/22, tripod.

9Introduction

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Digital Exposure Handbook
Basically, without a good understanding of exposure,
your images will never progress beyond the realm
of pleasing snapshots.
Exposure can be manipulated for creative effect
in so many different ways. For example, it can be
used to create the impression of movement, or to
freeze fast action that otherwise would be too quick
for the human eye to register. However, the skill isnt
just to know how to create such effects; you also
need to be able to judge when to employ certain
settings. This handbook will help you make the right
choices. It is designed to be an exhaustive manual
on the subject, covering every aspect of exposure as
well as offering helpful and practical advice on ways
to improve your photography in general.
My hope is that this guide will inspire you,
helping to open your eyes to the skills and techniques
required to manage and control exposure in order to
create images that succeed in relaying your artistic
vision. However, reading this book alone will not
improve your photography; you have to adopt and
implement the things you learn in your own picture
taking. After all, photography is a skill and, if you wish
to improve, it has to be practised.
X Church silhouetteIn many ways, there is no such thing as a correct
exposure. For example, technically speaking,
a silhouette is the result of poor exposure the
subject being grossly underexposed. However, no
one could deny that silhouettes create dramatic
and striking imagery.
Nikon D300, 2485mm (at 85mm), ISO 200, 2min at f/11, 10-stop ND, tripod.

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1 The basics of exposure

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1 Digital Exposure HandbookThe basics of exposurePhotography is derived from the Greek phos, meaning light, and graph, meaning to draw; therefore a photograph is a drawing made with light. Since the French lithographer Nicphore Nipce created the rst permanent photograph in 1826 by coating a pewter plate with asphaltum, controlling exposure has been the key fundamental of photography. Even in this digital age, exposure is still determined by the same three variable settings that have been used since its advent: the sensitivity of the photo-sensitive material used to record the image, shutter speed and lens aperture.
ISO equivalency rating
ISO (International Standards Organization) equivalency refers to a sensors sensitivity to light. It is a term that is adopted from lm photography, when lm was rated depending on the way it reacted to light. A low ISO rating or number is less sensitive to light, meaning it requires a longer exposure. In contrast, a high ISO equivalency is more sensitive to light, which in practical terms means it needs less exposure. Every doubling of the ISO speed halves the brightness of light, or the length of time required, to produce the correct exposure, or vice versa. The sensitivity of an image sensor is measured in much the same way as lm. For example, an ISO equivalency of 200 would react to light in an almost identical way to a roll of lm with the same rating. Digital cameras allow photographers the luxury of altering ISO sensitivity quickly and easily. Increasing ISO sensitivity is a useful way to generate a faster shutter speed in shooting situations where you wish to capture fast action or when working in low light.
Shutter speed
Also known as shutter time, shutter speed is the length of time the camera shutter remains open. It determines the amount of light entering the camera in order to expose the sensor. The duration of the shutter speed can be as brief as 1/8000sec or upwards of 30sec, depending on the light available
and also the effect the photographer desires. As with the lens aperture, one full stop change in shutter speed will either halve or double the amount of light reaching the sensor. For example, reducing the shutter time from 1/500sec to 1/250sec will double the length of time the shutter remains open and vice versa. The shutter speed greatly dictates how motion is depicted in the resulting photograph. A fast shutter time will freeze movement, while a slow speed can create subject blur (if the subject is moving), creating the feeling of motion and giving images added energy or interest.
T Brentor To ensure that suf cient light exposes the sensor
to record the scene or subject faithfully, an
appropriate combination of ISO sensitivity, lens
aperture and shutter speed needs to be selected.
Nikon D300, 1224mm (at 12mm), ISO 200, 3min at f/11, 10-stop ND, tripod.

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1The basics of exposureLens aperture
T Blurred tide For this image, I prioritized a slow shutter speed
to creatively blur the movement of the rising
tide. I was able to do this by selecting a low ISO
sensitivity, small aperture, and shoot in low light.
Nikon D700, 1735mm (at 26mm), ISO 200, 30sec at f/14, tripod.
in aperture doubles the amount of light reaching the image sensor, while each 1-stop reduction halves the amount of light. The aperture affects depth of eld (see page 46), with a large aperture creating a narrow depth of eld and a small aperture producing a wide depth of eld.
Summary
To achieve consistently accurate and faithful exposures, it is essential to have a good understanding of the three variables and their relationship to each another. Once you have selected an appropriate combination of lens aperture and shutter speed for a given ISO sensitivity a change in one will necessitate an equal and opposite change in the other. Quite simply, it is these three exposure variables that form the basics of exposure and photography.
The lens aperture is the size of the adjustable lens diaphragm, which dictates the amount of light allowed to reach the sensor. In isolation, its design can be compared to that of a human eye. Our pupils contract in bright conditions, needing less light to distinguish detail, while in low light our pupils require more light so grow larger. By altering the lens aperture, photographers are affecting the amount of light reaching the sensor. Apertures are measured using f-stops and, while all camera lenses are calibrated to the same measurement scale, the range of f-numbers varies from one lens to another, typically ranging from f/1.4 and up to f/32. Larger apertures (denoted by small f-numbers) allow light to reach the sensor more quickly, meaning less exposure time is needed. At small apertures (large f-number), it takes longer for sufcient light to expose the sensor, so therefore a longer exposure is required. Each 1-stop increase

16
1 Digital Exposure HandbookMetering
Metering is the way light is measured to determine the best exposure value for a particular scene or subject. There are two types of metering tool: the cameras built-in TTL (through the lens) metering system or a handheld device. The systems employed by todays digital cameras are highly sophisticated and accurate. However, they are not infallible and can be deceived in awkward lighting conditions for example, by backlighting (see page 107).
T Emerging leaves Modern metering may be highly accurate and
reliable, but it cannot predict the effect you are
striving to achieve artistically. Photographers
need to be aware of how light is measured, to
enable them to manipulate it creatively.
Nikon D200, 150mm, ISO 100, 1/100sec at f/9, tripod.
Re ected or incident light what is the difference?
Light is calculated in one of two ways: either by measuring the light re ecting off the subject (re ected light) or the amount fa...

Black + White Photography - Special Issue - Digital Exposure Handbook

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