Camera Settings Vs. Photometric Exposure
“Exposure value” is somewhat of a misnomer, because it indicates combinations of camera settings rather than the photometric quantity of luminous exposure Hv (aka photometric exposure), which is given by (Ray 2000, 310)
where
- Hv is the photometric / luminous exposure
- Ev is the image-plane illuminance (not EV, the exposure value)
- t is the exposure time
The illuminance Ev is controlled by the f-number but also depends on the scene luminance Lv. To avoid confusion, some authors (Ray 2000, 310) have used camera exposure to refer to combinations of camera settings. The 1964 ASA standard for automatic exposure controls for cameras, ASA PH2.15-1964, took the same approach, and also used the more descriptive term camera exposure settings.
Common practice among photographers is nonetheless to use “exposure” to refer to camera settings as well as to photometric exposure.
Read more about this topic: Exposure Value
Famous quotes containing the word camera:
“The camera can represent flesh so superbly that, if I dared, I would never photograph a figure without asking that figure to take its clothes off.”
—George Bernard Shaw (1856–1950)