[6-09] "Glossary (iii)"

ISO–Sensitivity of film or digital gain; techies will explain better but—how sensitive is this film to light? ISO100 requires more light to saturate than ISO200 (2^1), which requires double ISO400 (2^2) and double ISO800 (2^3). Digital offers a wider range; the D750 goes to 12.8k-52k; images lose fidelity in these conditions (noise)

Bokeh—the characteristic of objects where focus occurs behind or in front of the sensor; objects out of focus, rendering them indistinct, so some sharpness is lost; the most sought after characteristic in photography today

f64—a movement started in the 1920 focusing on images without bokeh (fully sharp); the opposite of bokeh; practitioners include Ansel Adams and Edward Weston; I suppose their cameras were large-format, had less depth of field, so an equivalent today might be ~f22 on 35mm format

Autofocus—a invention that automated the process how how a camera/photographer determines focal distance and calibrates the lens for this; an inherently complicated technology which made it possible for some specialities (sports, wildlife, wedding) because manual focus is too slow

TTL—also a new invention that automates flash power; think about flashlight: it can be too weak in bright areas, too bright in dim conditions; TTL fires a pre-flash, and then calibrates the flash power based on this nearly instantaneous calculation