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This would be a good way to use up a couple of out of date rolls.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.
From: "Terry and Tracey" <foxcroft@xxxxxxxxxxxxxxxxxxxxxx>
Reply-To: olympus@xxxxxxxxxxxxxxx
To: <olympus@xxxxxxxxxxxxxxx>
Subject: Re: [OM] Odd OM4 behavior - oops, nevermind.
Date: Mon, 21 Jun 1999 17:25:12 +1000
> However, I do have a question for the OM wizards. Does all film
available
> for 35mm have the same reflectance characteristics? It seems like a
rather
> large leap of faith for the OM designers to base an exposure on that
> assumption.
Big question mate. What's the light reflectance of unexposed film? We had
some threads about this a while ago. It seems Olympus set it up for
Kodachrome 64 (which fortunately I use). But there are differences between
films and between different batches of fthe same film.
Hey, just use K64!
Foxy
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