Aperture
Digital Photography
Fundamentals

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K Apple Computer, Inc.
© 2005 Apple Computer, Inc. All rights reserved.
No part of this publication may be reproduced or
transmitted for commercial purposes, such as selling
copies of this publication or for providing paid for
support services. Every effort has been made to ensure
that the information in this manual is accurate. Apple is
not responsible for printing or clerical errors.
The Apple logo is a trademark of Apple Computer, Inc.,
registered in the U.S. and other countries. Use of the
“keyboard” Apple logo (Option-Shift-K) for commercial
purposes without the prior written consent of Apple
may constitute trademark infringement and unfair
competition in violation of federal and state laws.
Apple, the Apple logo, Apple Cinema Display and
ColorSync are trademarks of Apple Computer, Inc.,
registered in the U.S. and other countries.
Aperture is a trademark of Apple Computer, Inc.

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Contents
1
Preface
5
An Introduction to Digital Photography Fundamentals
Chapter 1
7
How Digital Cameras Capture Images
7
Types of Digital Cameras
8
Digital Single-Lens Reflex (DSLR)
9
Digital Rangefinder
11
Camera Components and Concepts
11
Lens
12
Understanding Lens Multiplication with DSLRs
14
Understanding Digital Zoom
14
Aperture
15
Understanding Lens Speed
16
Shutter
17
Using Reciprocity to Compose Your Image
17
Digital Image Sensor
20
Memory Card
20
External Flash
21
Understanding RAW, JPEG, and TIFF
21
RAW
21
Why Shoot RAW Files?
22
JPEG
22
TIFF
22
Shooting Tips
22
Reducing Camera Shake
23
Minimizing Red-Eye in Your Photos
25
Reducing Digital Noise
Chapter 2
27
How Digital Images Are Displayed
27
The Human Eye’s Subjective View of Color
29
Understanding How the Eye Sees Light and Color
30
Sources of Light
30
The Color Temperature of Light
31
How White Balance Establishes Color Temperature

3

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31
Measuring the Intensity of Light
32
Bracketing the Exposure of an Image
33
Understanding How a Digital Image Is Displayed
33
Additive vs. Subtractive Color
34
Understanding Color Gamut
34
Displaying Images Onscreen
35
The Importance of Color Calibrating Your Display
35
Apple Cinema Displays Are Proof Perfect
36
Displaying Images in Print
36
Printer Types
Chapter 3
37
Understanding Resolution
37
Demystifying Resolution
37
Learning About Pixels
38
Learning About Bit Depth
40
How Resolution Measurement Changes from Device to Device
41
Mapping Resolution from Camera to Printer
41
Camera Resolution
42
Display Resolution
42
About the Differences Between CRT and Flat-Panel Display Resolutions
42
Printer Resolution
43
Calculating Color and Understanding Floating Point
43
Learning About Bit Depth and Quantization
44
Learning About the Relationship Between Floating Point and Bit Depth
45
Understanding How Aperture Uses Floating Point
Appendix
47
Credits
4
Contents

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e
An Introduction to Digital
r
efac
Photography Fundamentals
P
This document explains digital terminology for the
professional photographer who is new to computers
and digital photography.
Aperture is a powerful digital photography application designed to help you produce the
best images possible. However, many factors outside of Aperture can affect the quality of
your images. Being mindful of all these factors can help prevent undesirable results.
The following chapters explain how your camera captures a digital image, how images
are displayed onscreen and in print, and how cameras, displays, and printers measure
image resolution.

5

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How Digital Cameras
1
Capture Images
1
If you’ve previously shot film and are new to digital media,
this chapter is for you. Here you’ll find basic information
about the types of digital cameras, camera components
and concepts, and shooting tips.
People take photographs for many different reasons. Some take pictures for scientific
purposes, some shoot to document the world for the media, some make their living
shooting products for advertisements, and others shoot for enjoyment or purely artistic
purposes. Whatever your reason for picking up a camera and framing an image, an
understanding of how cameras work can help you improve the quality of your images.
This chapter covers:
 Types of Digital Cameras (p. 7)
 Camera Components and Concepts (p. 11)
 Understanding RAW, JPEG, and TIFF (p. 21)
 Shooting Tips (p. 22)
Types of Digital Cameras
In its most basic form, a digital camera is a photographic device consisting of a
lightproof box with a lens at one end, and a digital image sensor at the other in place
of the traditional film plane. Advances in digital photography are fast providing a wide
spectrum of features and options that can be challenging for the new digital
photographer to master.
There are two basic types of digital cameras: digital single-lens reflex (DSLR) and
digital rangefinder.

7

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Digital Single-Lens Reflex (DSLR)
This camera is named for the reflexing mirror that allows you to frame the image
through the lens prior to capturing the image. As light passes through the DSLR
camera’s lens, it falls onto a reflexing mirror and then passes through a prism to the
viewfinder. The viewfinder image corresponds to the actual image area. When the
picture is taken, the mirror reflexes, or moves up and out of the way, allowing the open
shutter to expose the digital image sensor, which captures the image. Most features on
a DSLR are adjustable, allowing for greater control over the captured image. Most DSLR
cameras also allow the use of interchangeable lenses, meaning you can swap lenses of
different focal lengths on the same camera body.
Viewfinder
Prism
(shows the actual
image frame)
Digital image sensor
Mirror
Lens
Processor
Reflexing mirror
(swung open)
8
Chapter 1 How Digital Cameras Capture Images

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Digital Rangefinder
There are two classes of digital rangefinder cameras: coincident rangefinder and
point-and-shoot.
Coincident Rangefinder
Unlike DLSR cameras, the coincident rangefinder does not provide the photographer
with the ability to view the subject through the lens. Instead, the coincident
rangefinder employs a mirror or prism that uses triangulation to unite the images seen
through the viewfinder and a secondary window to bring the subject into focus. The
photographer sees two images overlaid on top of one another in the viewfinder, and
the image is not in focus until there is a single image. As with DSLRs, most features in a
coincident rangefinder are adjustable, allowing for maximum control over the captured
image. An advantage to using a coincident rangefinder over a DSLR is that the lack of a
reflexing mirror significantly reduces camera shake. Camera shake is due to hand
movement or the vibration of the reflexing mirror found in a DSLR, and can cause
blurring of the image.
Beamsplitter
Light source
semitransparent mirror
Viewfinder
Light-gathering window
Semitransparent
mirror
Reflective
Image sensor
light
Rotating mirror/prism
Out of focus
In focus
(image overlays not aligned)
(image overlays aligned)
Chapter 1 How Digital Cameras Capture Images
9

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Digital Point-and-Shoot
This is a lightweight digital camera, aptly named after the two steps required of the
photographer to capture an image. Basically, point-and-shoot cameras require pointing
the camera and taking the picture without manually adjusting settings such as the
aperture, shutter speed, focus, and other settings that professional photographers
routinely set on more sophisticated cameras. Of course, some point-and-shoot digital
cameras do include adjustable aperture and shutter settings. Point-and-shoot digital
cameras are generally light and small, have built-in automatic flash, require no
adjusting of focus, and most often include an LCD display that allows you to view the
image through the lens in real time via the digital image sensor. Most manufacturers of
point-and-shoot cameras separate the viewfinder from the lens assembly to simplify
construction and achieve a compact size. The lens, aperture, and shutter are one
assembly, irremovable from the camera itself.
Viewfinder
LCD display
(shows an approximation
of the image frame)
Light source
Reflective
light
Digital image sensor
Lens
Because rangefinder cameras separate the optical path between the viewfinder and
the lens assembly, optical compression and frame indicators (guidelines) are used to
approximate the image’s frame. This approximation often causes subtle differences
between what the photographer sees in the viewfinder and what is captured in the
image. This is especially noticeable when the subject is close to the camera.
10
Chapter 1 How Digital Cameras Capture Images

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Document Outline

• Aperture Digital Photography Fundamentals
  • Contents
  • An Introduction to Digital Photography Fundamentals
  • How Digital Cameras Capture Images
    • Types of Digital Cameras
      • Digital Single-Lens Reflex (DSLR)
      • Digital Rangefinder
    • Camera Components and Concepts
      • Lens
      • Understanding Lens Multiplication with DSLRs
      • Understanding Digital Zoom
      • Aperture
      • Understanding Lens Speed
      • Shutter
      • Using Reciprocity to Compose Your Image
      • Digital Image Sensor
      • Memory Card
      • External Flash
    • Understanding RAW, JPEG, and TIFF
      • RAW
      • Why Shoot RAW Files?
      • JPEG
      • TIFF
    • Shooting Tips
      • Reducing Camera Shake
      • Minimizing Red-Eye in Your Photos
      • Reducing Digital Noise
  • How Digital Images Are Displayed
    • The Human Eyes Subjective View of Color
    • Understanding How the Eye Sees Light and Color
    • Sources of Light
      • The Color Temperature of Light
      • How White Balance Establishes Color Temperature
      • Measuring the Intensity of Light
      • Bracketing the Exposure of an Image
    • Understanding How a Digital Image Is Displayed
      • Additive vs. Subtractive Color
      • Understanding Color Gamut
      • Displaying Images Onscreen
      • The Importance of Color Calibrating Your Display
      • Apple Cinema Displays Are Proof Perfect
      • Displaying Images in Print
      • Printer Types
  • Understanding Resolution
    • Demystifying Resolution
      • Learning About Pixels
      • Learning About Bit Depth
    • How Resolution Measurement Changes from Device to Device
    • Mapping Resolution from Camera to Printer
      • Camera Resolution
      • Display Resolution
      • About the Differences Between CRT and Flat-Panel Display Resolutions
      • Printer Resolution
    • Calculating Color and Understanding Floating Point
      • Learning About Bit Depth and Quantization
      • Learning About the Relationship Between Floating Point and Bit Depth
      • Understanding How Aperture Uses Floating Point

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