[Leica] Underexposure in Tungsten Light

[r.s.taylor at comcast.net (Richard S. Taylor)]

It's the curse of the engineering mind, I fear.  :-))

>Another factor about tungsten light souces is that they more correctly
>treated as point sources even when relatively close to them so light
>intensity falls off inversely proportional to distance squared.
>
>But flourescent fixtures typically look like planar sources or line
>sources which, if you're relatively close to them (and if I'm
>remembering my rad-con rules of thumb appropriately) fall off just
>inversely proportional to distance. (Assuming the ceiling is
>reasonably low).
>
>This would account for tungsten sources giving you a hard time because
>light fall-off across an image would be more severe.
>
>I've not looked at the spectrum of most incandescent bulbs but for
>most vendors you can find those graphs on the net and compare them to
>the published response graphs of the film you use.
>
>I'd never thought about light in quite these terms before. D'oh!
>
>Adam
>
>
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-- 
Regards,

Dick
Boston MA