Learning Photography Course - 10. Digital, from Sensor to Finished Picture
Module 10 of the Learning Photography Course: digital photography, from the sensor to the finished picture.
The sensor as a grid of photosites that collect charge, and why a clipped highlight is a full well rather than a bright value. CCD against CMOS, back-side illuminated and stacked sensors, and rolling shutter. Why a sensor is colour-blind, and the Bayer array that fixes it — US patent 3,971,065, Bryce Bayer of Eastman Kodak, granted 1976, with half its filters green — so that two thirds of the colour values in every pixel are estimated by demosaicing. X-Trans, Foveon, monochrome sensors and the anti-aliasing filter.
Noise and dynamic range: shot noise as the square root of the light itself, worked with real numbers; read and pattern noise; dual gain; and why more megapixels is not, by itself, more noise. Raw against JPEG: what raw contains, what the JPEG engine decides and discards, 8-bit baseline JPEG (ITU-T T.81) against 12- and 14-bit raw, and when JPEG is the right answer.
Getting pictures off and not losing them: SD, microSD and CFexpress; what the SD Association's speed classes actually guarantee (V30 is a 30 MB/s minimum sustained write, not a top speed); readers, cables, tethering and wireless; ingest, folder naming that survives ten years, and the 3-2-1 backup rule as set out by the US NCCIC in 2012.
The catalogue, selecting from four hundred frames to twelve, a sane editing order, and colour management: sRGB as defined in 1996 by Hewlett-Packard and Microsoft, Adobe RGB (1998) and exactly where it differs, why prints come out dark, output sharpening, metadata and soft proofing.
Educational documentary. Not financial or investment advice.
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Sources and credits
Primary sources
- US Patent 3,971,065, 'Color imaging array', inventor Bryce E. Bayer, assignee Eastman Kodak Co, filed 5 March 1975, granted 20 July 1976 Green at every other position (half the elements); the eye's limited ability to discern blue detail.
- Michael Stokes (HP), Matthew Anderson (Microsoft), Srinivasan Chandrasekar (Microsoft), Ricardo Motta (HP), 'A Standard Default Color Space for the Internet - sRGB', Version 1.10, 5 November 1996 (w3.org) — primaries, D65 white, transfer function, 80 cd/m² reference. Later standardised as IEC 61966-2-1, which was not read.
- Adobe Systems, 'Adobe RGB (1998) Color Image Encoding', Version 2005-05, May 2005 — primaries (green 0.21, 0.71), D65 white, gamma 2.19921875, 160 cd/m² reference white.
- SD Association, 'Speed Class' (sdcard.org), last modified 31 October 2023 — C10 10 MB/s, U3 30 MB/s, V30 30 MB/s, V90 90 MB/s as minimum sustained sequential write.
- ISO/CIE 11664-2:2022, CIE standard illuminants.
Not regulated financial advice.