Physics is fundamental to all aspects of digital photography. This book works through the physics underlying the photographic imaging chain, from image capture through to the production of a viewable output digital image. It provides an invaluable insight into the connections between imaging science and photographic practice and is intended for use by both graduate students and established researchers. In this updated and expanded new edition, the material has been re-organised and extensively rewritten and the figures have been enhanced.
Author(s): D. A. Rowlands
Series: IOP Series in Emerging Technologies in Optics and Photonics
Edition: 2
Publisher: IOP Publishing
Year: 2020
Language: English
Pages: 374
City: Bristol
Preface
Author biography
D A Rowlands
Abbreviations
Chapter 1 Photographic optics
1.1 Optical image formation
1.1.1 Refraction
1.1.2 Lens design
1.1.3 Paraxial imaging
1.1.4 Gaussian optics
1.1.5 Compound lenses: ynu raytrace
1.1.6 Principal planes
1.1.7 Gaussian conjugate equation
1.1.8 Thick and thin lenses
1.1.9 Focal length
1.1.10 Magnification
1.1.11 Lens aberrations
1.2 Focusing
1.2.1 Unit focusing
1.2.2 Internal focusing
1.2.3 Single lens reflex cameras
1.2.4 Phase-detect autofocus
1.3 Framing
1.3.1 Entrance and exit pupils
1.3.2 Chief rays
1.3.3 Pupil magnification
1.3.4 Angular field of view formula
1.3.5 Focus breathing
1.3.6 Focal length multiplier
1.3.7 Perspective
1.3.8 Keystone distortion
1.4 Depth of field
1.4.1 Circle of confusion
1.4.2 Depth of field formulae
1.4.3 Depth of field control
1.4.4 Hyperfocal distance
1.4.5 Focus and recompose limits
1.4.6 Bokeh
1.5 Photometric exposure
1.5.1 Photometry
1.5.2 Flux emitted into a cone
1.5.3 Relative aperture
1.5.4 f-number
1.5.5 Working f-number
1.5.6 f-stop
1.5.7 Natural vignetting
1.5.8 Camera equation
1.5.9 Shutters
1.5.10 f-number for aplanatic lenses
References
Chapter 2 Digital output and exposure strategy
2.1 Raw data
2.1.1 Sensor response
2.1.2 Colour
2.1.3 Dynamic range transfer
2.2 Digital output levels
2.2.1 Bit depth reduction
2.2.2 Posterisation
2.2.3 Lightness
2.2.4 Gamma encoding
2.2.5 Gamma decoding
2.3 Image dynamic range
2.3.1 Gamma curves
2.3.2 Tone curves
2.3.3 Raw headroom
2.3.4 Shadow and highlight dynamic range
2.4 Histograms
2.4.1 Luminance histograms
2.4.2 Image histograms
2.5 Average photometry
2.5.1 Reflected light meter equation
2.5.2 Proportionality constant
2.5.3 Photographic constant
2.5.4 Hand-held meter calibration constant
2.5.5 Average scene luminance
2.5.6 Exposure value
2.6 Exposure index
2.6.1 ISO speed
2.6.2 Standard output sensitivity
2.6.3 Recommended exposure index
2.6.4 Extended highlights
2.7 Advanced metering
2.7.1 Exposure compensation
2.7.2 In-camera metering modes
2.7.3 Incident light metering
2.8 Exposure modes
2.8.1 Aperture priority
2.8.2 Shutter priority
2.8.3 Program mode
2.8.4 Manual mode
2.9 Photographic lighting
2.9.1 Sunrise and sunset
2.10 Neutral density filters
2.10.1 Graduated neutral density filters
2.11 Polarizing filters
2.11.1 Malus’ law
2.11.2 Surface reflections
2.11.3 Blue skies
2.11.4 Circular polarizing filters
2.12 High dynamic range
2.12.1 High dynamic range imaging
2.12.2 Tone mapping
2.13 Image display
2.13.1 Luma
2.13.2 Display luminance
2.13.3 Display dynamic range
References
Chapter 3 Raw data model
3.1 Linear systems theory
3.1.1 Radiometry
3.1.2 Ideal optical image
3.1.3 Point spread function (PSF)
3.1.4 Linear shift invariance
3.1.5 Convolution: derivation
3.1.6 Convolution: examples
3.1.7 Optical transfer function
3.1.8 Modulation transfer function (MTF)
3.1.9 Phase transfer function
3.1.10 Model camera system
3.2 Optics
3.2.1 Wave optics
3.2.2 Huygens–Fresnel principle
3.2.3 Aperture diffraction PSF
3.2.4 Circular aperture: Airy disk
3.2.5 Aperture diffraction MTF
3.2.6 Aberrations: wavefront error
3.3 Sensor
3.3.1 Spatial averaging
3.3.2 Detector-aperture PSF
3.3.3 Sampling
3.3.4 Detector-aperture MTF
3.4 Optical low-pass filter
3.4.1 Function sampling
3.4.2 Replicated spectra
3.4.3 Reconstruction
3.4.4 Aliasing
3.4.5 Sensor Nyquist frequency
3.4.6 Pre-filtering
3.4.7 Four-spot filter PSF
3.4.8 Four-spot filter MTF
3.5 Sampled convolved image
3.5.1 Model camera system PSF
3.5.2 Model camera system MTF
3.6 Charge signal
3.6.1 Sampled spectral exposure
3.6.2 Photoelements
3.6.3 Colour filter array
3.6.4 Camera response functions
3.6.5 Polychromatic PSF and MTF
3.6.6 Charge detection
3.7 Analog-to-digital conversion
3.7.1 Programmable ISO gain
3.7.2 Digital numbers
3.7.3 Conversion factor
3.7.4 Bias offset
3.8 Noise
3.8.1 Photon shot noise
3.8.2 Read noise
3.8.3 Dark current shot noise
3.8.4 Noise power
3.8.5 Fixed pattern noise
3.9 Noise measurement
3.9.1 Conversion factor measurement
3.9.2 Read noise measurement
3.9.3 Noise models
References
Chapter 4 Raw conversion
4.1 Reference colour spaces
4.1.1 Theory of colour
4.1.2 Eye cone response functions
4.1.3 Colour-matching functions
4.1.4 Units
4.1.5 Standard luminosity function
4.1.6 CIE RGB colour space
4.1.7 rg chromaticity diagram
4.1.8 CIE XYZ colour space
4.1.9 xy chromaticity diagram
4.1.10 Absolute colourimetry
4.1.11 Relative colourimetry
4.1.12 Reference white
4.2 Illumination
4.2.1 Colour temperature
4.2.2 Correlated colour temperature
4.2.3 White point
4.2.4 Standard illuminants
4.3 Camera raw space
4.3.1 Raw channels
4.3.2 Colour demosaicing
4.3.3 Raw pixel vectors
4.3.4 Camera raw space primaries
4.3.5 Camera raw space reference white
4.4 Camera colour characterisation
4.4.1 Luther–Ives condition
4.4.2 Raw to CIE XYZ
4.4.3 Colour difference: CIE LAB
4.4.4 Transformation matrix normalisation
4.5 Output-referred colour spaces
4.5.1 sRGB colour space: linear form
4.5.2 CIE XYZ D65 to sRGB D65
4.5.3 Raw D65 to sRGB D65
4.6 White balance
4.6.1 Adopted white
4.6.2 Chromatic adaptation transforms
4.6.3 Raw channel multipliers
4.7 Strategy 1: transformation matrices + CAT
4.8 Strategy 2: raw channel multipliers + rotation matrix
4.8.1 Traditional digital cameras
4.8.2 dcraw
4.9 Adobe DNG
4.9.1 Method 1: transformation matrix + CAT
4.9.2 Method 2: raw channel multipliers + forward matrix
4.10 sRGB colour space: nonlinear form
4.10.1 sRGB digital output levels
4.10.2 sRGB colour cube
4.11 Raw processing workflow
4.11.1 Colour management
4.11.2 Maximal colour strategy
4.11.3 16-bit TIFF files
4.11.4 Adobe Photoshop colour settings
4.11.5 Image resizing
References
Chapter 5 Camera image quality
5.1 Cross-format comparisons
5.1.1 Equivalence and image quality
5.1.2 Generalised equivalence theory
5.1.3 Proof of equivalence theory
5.2 Perceived resolution
5.2.1 Observer resolving power
5.2.2 Standard viewing conditions
5.2.3 Circle of confusion: standard value
5.2.4 Circle of confusion: custom value
5.2.5 Circle of confusion: derivation
5.2.6 Depth of focus
5.3 Lens MTF
5.3.1 Lens MTF: standard viewing conditions
5.3.2 Lens MTF: lens resolving power
5.3.3 Cross-format comparisons
5.3.4 Limitations of lens MTF
5.4 Camera system MTF
5.4.1 Cross-format comparisons
5.5 Camera system resolving power
5.5.1 Model camera system
5.6 Perceived image sharpness
5.6.1 MTF50
5.6.2 Example: pixel count
5.6.3 Subjective quality factor
5.7 Image resampling
5.7.1 Upsampling
5.7.2 Downsampling
5.8 Signal-to-noise ratio (SNR)
5.8.1 SNR and ISO setting
5.8.2 SNR: output-referred units
5.8.3 SNR: input-referred units
5.8.4 ISO invariance
5.8.5 SNR and pixel count
5.8.6 SNR per unit area
5.8.7 SNR: cross-format comparisons
5.8.8 Raw ISO values
5.9 Raw dynamic range
5.9.1 Raw dynamic range per photosite
5.9.2 Sensor dynamic range
5.9.3 Perceivable dynamic range
5.10 Practical strategies
5.10.1 Object resolution
5.10.2 Diffraction softening
5.10.3 Non-destructive noise reduction
5.10.4 Exposing to the right (ETTR)
5.10.5 ETTR: variable exposure
5.10.6 ETTR: fixed exposure
References
Index
