Exposure Book Chapters


Photographic Exposure Calculations and Camera Operation
by Michael G. Prais, Ph.D.

Introduction and Motivation
Exposure and the Range of Exposures
Calculating with Full and Fractional Stops
Illuminance and Luminance
Scenic Exposure and Camera Operation
Quantities and Units
Photosensitive Arrays and Standard Photosensitive Characteristics

Solid-state Photosensitive Arrays
Photosensitive Exposure Range
Photosensitivity, Speed Point Exposure and Reference Exposure
Midtone Exposure, Midtone Shift and Exposure Meter Constant
Standard Photosensitive Characteristics
Emulsion Speed Points and Standard Photosensitive Exposure Ranges
Solid-state Speed Points and Standard Photosensitive Exposure Ranges
Spatial Resolution
Modulation Transfer Function and Spatial Response Function
Limiting (Nyquist) Spatial Frequencies of Solid-state Arrays
Spatial Resolution and Depth of Field
Tonal Resolution and Dynamic Range
ISO Equivalents for Solid-state Photosensitive Arrays
Opto-Electronic Conversion Functions (OECFs)
Photosensitive Exposure Latitude and Film Canister (DX) Coding
Exposure Compensation and Exposure in the Photosensitive Exposure Range
Problems Accepting the Manufacturer’s Photosensitivity
Determining the Extent of Your Photosensitive Exposure Range

Matching the Scenic Exposure Range to the Photosensitive Exposure Range
Exposure Calculations

Calculating the Relative Shutter Speed Using the Sunny f/16 Rule
Calculating the Relative Shutter Speed Using the Root Aperture Rule
Calculating the Response Range of Your Camera

Understanding and Misunderstanding Exposure Metering

Determination of Camera Settings:
Guessing and Measuring the Quantity of Light from Scenes
A Comparison of Meters as Tools
Meters as Measuring Devices
Meters as Calculation Devices
Representative Values
The 18% Myth
Solving the 18% Problem: Scene-dependent Quantities
The K-Factor Problem
Preferred Photosensitivities

The Exposure Process

Your Photosensitive Exposure Range and Your Target Exposure
Your Scenic Exposure Range and Your Representative Exposure
Matching Your Representative Exposure to Your Target Exposure

The Whole Process
The Zone System
Comparison with the Zone System
Rewind and Review
Appendix A: Safety Factors
Appendix B: Problems with Standards Documentation

Exposure Meters and Scene-dependent Quantities
ISO Speed Ratings for “Digital” Cameras
Opto-Electronic Conversion Functions

Appendix C: The Relation to and Criticism of the APEX Equation
Appendix D: Derivation of the Illumination Equation
Appendix E: Linear Perspective

Zero-Point Perspective
One-Point Perspective
Two-Point Perspective
Three-Point Perspective
Relative Movements of the Lens and the Photosensitive Array

Appendix F: Field of View
Appendix G: Recording Information about Image Creation

Information about Emulsion and Solid-state Images
Information about Solid-state Images

Appendix H: Derivation of Depth of Field without Approximation
Appendix I: Field of Focus Tables
Symbols and Abbreviations

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