Re: Bellows factor

That was my instinct, Guillermo, and thanks for your
answer.

Funny thing is, I tried it yesterday at a minute and a
half--my rough calculation, which was close to your
suggested 84.5 seconds--and it completely overexposed
the film. It was all white (using Polaroid Type 55).
Then I tried it indoors in a setting that I know from
experience needs about 45 minutes. I gave it about an
hour--very little more than what I would normally—and
the expoure was more or less correct. In other words,
it was behaving very much like the extension had no
effect at all. Wonder why?

Colin

> There is no "rule of thumb", just plain physics of
> light.
> This case is in no way different than if you were
> using a glass lens.
>
> > If I would expect a 2-second exposure outside in
> full
> > sunlight with a 5.0CM "focal length", for example,
> > what would be a theoretical equivalent at 32.5 CM?
>
> 84.5 seconds (uncorrected for reciprocity, time)
>
> Guillermo
>
>
>
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Received on Fri Nov 30 23:34:43 2001