From: shannon stoney (sstoney@pdq.net)
Date: 04/12/02-04:34:42 PM Z
I recently read a formula for figuring pinhole exposures that I can't
figure out. It goes as follows:
-Set your light meter to an f stop and call it A.
-The meter will give you an exposure time that you call S.
-Figure your pinhole aperture and call it B.
-Now find the correct exposure time with the formula and call it X
-S B 2/A 2=X
My questions are:
1. what number do you use for the pinhole aperture? the fraction of
an inch that it is (like say 1/64) or its measurement in decimals
(0.0156) or the f stop that it is (420)? I am thinking probably the
latter.
2. IS SB2 the numerator and A2 the denominator? If so, why is there
a two in the numerator and the denominator? Don't they cancel each
other out? How do you figure this formula, in practical terms?
3. Is there a pinhole list?
--shannon
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