Roger,
Quite correct. Trevor asked about removing one lamp and how much underexposure
one would experience. I said 1 stop. Well, one stop from being 2 stops under!!
or three stops under correct exposure. No?
andy
Roger Eichhorn wrote:
Andy,
If the two lights are closely spaced, and have identical spectra, the intensity of the light reflected from any surface that enters the camera will be reduced by 1/2 if one of the lights is removed. That's one stop more, or three in this case. Conversely, if two lights are two stops under, four lights will only double the intensity so we're now one stop under. We have to double the number of lights again to double the intensity, so eight lights in all. Is that the correct way to look at it?
Roger
