----------
> From: Michael A. Covington <covington@xxxxxxxxxxxxxx>
> To: olympus@xxxxxxxxxxxxxxx
> Subject: [OM] Reciprocity failure and Olympus auto exposure
> Date: Friday, September 04, 1998 9:26 PM
>
> Quoth Red Rover:
>
> "I've read of reciprocity failure, where film, when taken at long
> exposures, usually requires much more exposure then a meter calls for.
I've
> learned that my Om2s can take auto exposed pictures at lengths of up to 2
> minutes, but wouldn't this be an incorrect exposure due to reciprocity?
> Should I see how long the camera takes the picture and then multiply this
> time for the specific film I'm using for the next shot? Thanks."
>
> I'm an astrophotographer and reciprocity failure is a big part of my life
--
> but I don't normally use exposure meters on the stars :)
>
> Newer films have much less reciprocity failure than older films. For
> example, T400 CN has next to none, and Elite Chrome 200 has less than any
> other color film I've tried.
>
> My impression is that the OM-2S includes some reciprocity correction, but
I
> haven't tried to measure it. In any case, if you need an exposure of
more
> than a few seconds, you probably aren't aiming for precise exposure
anyway.
> With an OM-2S you will get *pictures*, which is a lot more than you can
say
> for my new N*k*n N70, which seems to feel that anything longer than about
1
> second is "LO"!
>
> Michael A. Covington / AI Center / The University of Georgia
> http://www.ai.uga.edu/~mc http://www.mindspring.com/~covington <><
>
I also have similar experience in the pass, my OM-2S gave me a non linear
response in shutter speed, it trend to increase below around 1/4s. For
example at 1/4s the shutter actually exposed at 1/2, when up to around a
few second (say 4-8s) the shutter stay open for more than a minute. I have
performed a comparsion test with my OM2n to confirm this. At the beginning
I also thought it may included reciprocity correction. But finally I took
it for a checkup, the technician told me the computer circuit was failed
and need a replacement, it cost US120. But at that time, I only bought the
camera at US150, so I refused. Finally I sold the camera to a second hand
camera shop for US120.
C.H.Ling
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