Tom Ferguson (tomf2468@pipeline.com)
Thu, 20 May 1999 06:57:21 -0700
>From: Carl Weese <cjweese@wtco.net>
>John Erbes wrote:
>>
>> Gary,
>> It's my understanding that film speeds are slower indoors
typically by
>a
>> stop or so as compared to their rated outdoor speed. I don't know
>why,
>> but I'm sure that someone on the list will explain.
>>
>> John Erbes
>
>At one time manufacturers gave a _tungsten_ film speed for b&w materials
>that was typically just a picky 1/3 stop slower than the daylight speed,
>this because typical pan films were slightly less sensitive to red light
>than blue and tungsten light is much lower in color temperature than
>typical daylight. But this isn't true of most modern films, and in any
>case wouldn't apply to strobes at all (which are daylight or higher in
>color temperature) or flourescents, which are now more common "indoor"
>light sources anywhere except private homes.
>
>---Carl
Carl is correct. Modern film's daylight versus tungsten speed is
within 1/3 stop (at least when I measured it). What I don't
think has been discussed, and may be Gary's problem if he isn't
shooting this completely with strobe, is reciprocity. When you
expose most films for longer than 1 second, you loose exposure.
Many indoor shots require such long exposures, and often (usualy)
the manufacturer's recommended compensations are (for me) too
optimistic.
Hope that helps
Tom
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:34