-----Original Message-----
From: gary edwards <maitani@xxxxxxxxxxx>
To: olympus@xxxxxxxxxxxxxxx <olympus@xxxxxxxxxxxxxxx>
Date: Monday, June 21, 1999 9:02 AM
Subject: Re: [OM] Odd OM4 behavior - oops, nevermind.
>Film reflectivity variation is a trivial issue (I think). If it concerns
>you, here is how to test for variation. Set up you OTF capable OM looking
>at a constant illumination scene. A solid wall dimly illuminated by
>artificial light would be good. Select an aperture that gives you an
>automatic exposure of, say, 60 s. Shoot 36 test shots with one film type,
>carefully timing the exposure with a stopwatch. Load another type of film
>and, without changing the film speed setting (or anything else), make 36
>more test shots (the more the better to average out measurment errors).
>This would be a good way to use up a couple of out of date rolls. Throw
the
>exposed film away and report your results. Include the number of samples,
>the variation of each film type (standard deviation of 36 measurements),
and
>the film types. My bet is that the standard deviation for each roll will
be
>about the same magnitude as the difference between rolls.
>
Boy am I confused! Is the intention to take 36 identical test shots each one
at 60 seconds [..."60 s"] with a constant aperture and then repeat the same
exercise with another but different brand of 36 exposure film? The two
exposed reels of film are then "thow[n] away....." and the the results are
reported. What are the "results" that are being reported upon? What is all
the data that is being used to calculate the standard deviation? Standard
deviation of what?
jh
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