At 16:43 21.09.01, Paul Farrar wrote:
Ev is not a measure of light and has no functional relationship
with light levels. It is a measure of exposure only, and is a
function of shutter speed and aperture, and nothing else. Light
meters can be set to give Ev readouts, but the value shown is
a recommended exposure, which will change with the ISO setting,
not a measure of light.
What you have written is correct as far as I can tell, but you have omittet
that EV can also be written as a sum of light value (LV) and speed value
(SV). For any given film speed there will be a relationship between EV and
foot-candles, and therefor also between EV and lux. Nevertheless, you are
correct that EV is not a direct messure of light levels.
Regards,
Thomas Bryhn
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