Science for theCurious Photographer

An Introduction to the Science of Photography

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Science for theCurious Photographer

An Introduction to the Science of Photography

a k peters, ltd.natick, massachusetts

Charles S. Johnson, Jr.

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Editorial, Sales, and Customer Service Offi ceA K Peters, Ltd.5 Commonwealth RoadNatick, MA 01760www.akpeters.com

Copyright © 2010 by Charles S. Johnson, Jr.

All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in any form, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission from the copyright owner.

Th e following products and trademarks are used throughout the book: AT&T Bell Labs, B+W, Canon, Cibach-rome, Ciga-Geigy Corp., CoCam?, Cokin, ColorMunki, CombineZM (freeware), Dynamic-Photo HDR, East-man Kodak, Kenko, Kodak, Kodachrome, Epson, Fairchild Semiconductor, Focus Magic, FocalBlade, Foveon, Fujichrome Provia, Fujifi lm, Helicon Focus, Heliopan, Hoya, Ilfochrome, Intel, Kirk, Life Pixel, Leica, MaxMax, Manfrotto, Nikon, Olympus, Photokit Sharpener, Photomatix, PhotoPro RGB, Photoshop, Polaroid Corp., Rol-leicord, Schott, Schneider-Kreuznach, Sigma, Sony, Spyper3, Tamron, Texas Instruments, Tiffi n, Wratten, and Zeiss.

Library of Congress Cataloging-in-Publication Data

Johnson, Charles S. (Charles Sidney), 1936 – Science for the curious photographer : an introduction to the science of photography / Charles S. Johnson, Jr. p. cm. Includes bibliographical references and index. ISBN 978-1-56881-581-7 (alk. paper) 1. Photography. I. Title. TR146.J556 2010

770—dc22

2009047521

Printed in India14 13 12 11 10 10 9 8 7 6 5 4 3 2 1

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To Ellen, my wife and best friend

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vii

Preface ix

chapter What Is Photography? 1

chapter What Is Light? 5

chapter Th e Camera—An Introduction 9

chapter Images: What Is Perspective? 15

chapter Why Does a Camera Need a Lens? 19

chapter Elementary Optics: How Do Lenses Work? 23

chapter Th e Simple Th in Lens and What It Does 27

chapter How to Make Lenses that Are Good Enough for Photography 31

chapter Coming to Terms with Real Camera Lenses 41

Table of Contents

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viii

chapter Fisheye Lenses and How Th ey Capture the Whole Sky 49

chapter What Is an Equivalent Image? 55

chapter How to Get Very High Magnifi cation 63

chapter Do We Need Filters Anymore? 77

chapter Th e Limits of Human Vision 89

chapter How Can Color Be Managed? 95

chapter Image Capture and Processing 113

chapter What Is Perceived Image Quality? 125

chapter Th e Creation and Appreciation of Art in Photography 137

appendix aHistorical Note on Enlargers 149

appendix bWhat Is Behind the Rules of Optics? 151

appendix cDerivation of the Lensmaker’s Equation 155

appendix dGaussian Optics and the Principal Planes 157

appendix eA Macro Lens with Attachments 159

appendix fCapturing Photons with Photographic Film 161

appendix gMicroelectronics and the Path to Digital Sensors 167

appendix hIrradiance and Illuminance Units 169

index 181

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I ordered a Rolleicord III medium format camera. It served me well and is still functional.

From the beginning I was fascinated by all aspects of photography. I love the equipment, the techniques, the processing of images, and, of course, the chance to photograph interesting things. Photography also provided a summer job and a doorway to business and social interactions. Photographs documenting those years reveal small-town life in the 1950s and a few cheesecake pictures as well. My career as a scientist and a uni-versity professor took me away from photography for many years, but in the past decade I have re-turned to that early love. I spend a lot of time on nature photography now, and I enjoy photo shoots with the Carolinas’ Nature Photographers Asso-ciation (CNPA). Of course, everything is digital, so the chemical darkroom is no longer necessary. Th is has given me a new world of opportunities and an array of new subjects to understand.

My love of photography started very early. As a teenager I worked in a small full-service photography shop. Portraits were

made, events were photographed, snapshots were developed and printed, and equipment was sold. From that experience, I learned about photographic techniques and the value of quality cameras and lenses. I started developing and enlarging my own photographs, and I searched for ways to learn more. Fortunately, I found the book Lenses in Photography by Rudolf Kingslake in the photography shop, and I studied it diligently. I still have that book and refer to it frequently. At that time (the 1950s), my uncle was serving with the Air Force in Germany, and he was able to buy fi ne cameras for me. First, I got a Zeiss Ikonta 35. It was bare bones, with no rangefi nder or light meter, but it had a wonderful Zeiss Tessar f�2.8 lens. It was great for documenting sports and other high school events. Later, when I started do-ing freelance photography (while still in high school),

Preface

ix

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x preface

On the other hand, some great photographers and other artists as well have benefi ted from a knowl-edge of their media and ways to get the most out of it: Ansel Adams comes to mind. In addition to making awe-inspiring photographs, Adams wrote technical books on cameras, negatives, and prints. To each his/her own, but I believe that in photog-raphy, as elsewhere, knowledge is power.

I have worked on this book for four years, try-ing the patience of my wife and friends. I appreci-ate comments from all those who have read sec-tions of it at various stages of its gestation. I am sure to leave out some generous and helpful peo-ple, but here is at least a partial list of those who have contributed at various times with corrections and advice: John Fowler, Archibald Fripp, Richard Jarnagin, and Calvin Wong.

—CHARLES S. JOHNSON, JR.

In my case, understanding the way photog-raphy works has increased enjoyment of it. Each new question is a challenge. Th e process of work-ing through the concepts of photography from basic optics and image sensors to human percep-tion of color and the appreciation of beauty was an exhilarating experience for me. I have written this book for those who also enjoy photography, and who want to know more about their photo-graphic equipment and the operation of their eyes and brain as well. Th e book is specifi cally aimed at those who enjoy science and are not afraid of a little math. Of course, perfectly good photo-graphs can be made by those who have no inter-est in the scientifi c side of photography. Th ey see a clean separation between the scientifi c part and the artistic part, and they reject the scientifi c part.

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