Re: SFX200 ISO Ratings

["James D. Goff" <jdgoff@xxxxxxxx>]

At 06:15 PM 2/7/97 GMT, you wrote:
> 
> Does anyone have any recommendations for adjusting the ISO setting when
>using a #25 red filter,
> i.e., to achieve "correct" TTL + TTF meter readings in daylight, e.g., 1)
>continue to use ISO 200, 
>2) use ISO ~1000  (200*4.7), 3) something else? 
>(I know the normal (no filter) rating for the film is ISO 200.)
>
>Thank you
>
>Tony Brintzenhoff
>
>Dear Tony,
It's possible I don't understand your question, but it is my understanding
that TTL metering corrects for filters. I can say that my experience
validates that assumption with very few exceptions which probably is caused
by  a difference in sensitivity between the film and the meter. With IR, of
course, not meter that I am aware provides valid IR sensitivity. Filter
factor correction in this instance would not be completely valid, also. I
usually do not rely on meters--either hand held on on-board TTl--for
exposure determination, but experience. I have kept a log of exposures under
different conditions, with and without filters, etc. that I rely upon. I
hope I have not insulted you by telling you something you already know.
James......


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