Re: self-intro

[Stan Yoder <syoder+@andrew.cmu.edu>]

Excerpts from mail: 23-Apr-96 Re: self-intro by tmydosh@servtech.com 
> What is a "dry curtain"?

   I've seen this term in  ads, etc., and asked Marc Small (who of
course can speak for himself at this point), who said it meant just
that: curtain material dried out, mostly from inactivity. One result
(and what I meant to convey) is that such curtains typically leak light,
a la pinholes. All three bodies the net seller sent me did that, 'tho
with the last it did not show on test exposures.
    I put all three to this test (with ISO 100 or 200 color neg. film):
with the iris open to f/2 and the shutter wound, I uncapped the lens and
pointed the camera at the sky (no, not directly at old sol!) for 20-30
seconds. Capped, released. That tested the leading curtain. Still
capped, wound on, released, uncapped, pointed at sky again. Recapped.
That tested the trailing curtain.
    The two frames should have been entirely clear, but there were
exposed spots. All three bodies showed this. The first two also showed
corresponding white spots on the prints. The third did not: apparently
its leakge was not severe enough to show up in ordinary use (camera
around neck between pics, stopped down to 5.6 or 8, not usually pointed
at sky).
    In light of the mixed results described, I guess one could call the
above a pretty severe test. OTOH, the purpose of a shutter is to control
the passage of light, all or none, eh? And for what I had paid this
seller, I didn't think I should have to invest additional having the
curtains replaced.

Stan Yoder
Pittsburgh