Manual and auto slides shot at the same setting will not necessarily match,
it would be "nice" if they did. Both slides can be acceptable, though
comparing 2 can make one think something is "wrong".
Expecting them to match is a little bit much considering all the tolerances
involved. Manual meter could be could be off 1/4 stop one way, the shutter
speed fast or slow, in the other direction. That's a half stop right there.
Auto meter could be off the same amount and auto shutter speed off too.
Don't forget to figure in the 0.000000e+00rror in the f stop of your lens, the
tolerance of the ASA of your film, and some errors in processing.
_________________________________
John Hermanson www.zuiko.com
Camtech, Olympus Sales & Service since 1977
21 South Lane, Huntington NY 11743-4714
631-424-2121 For Free Olympus manuals,
please call 1-800-221-3000
_________________________________
----- Original Message -----
From: "Winsor Crosby" <wincros@xxxxxxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Wednesday, June 12, 2002 2:22 PM
Subject: Re: [OM] OM 4 (Auto) - Shutter speeds
Angel,
>
> If the row of bars is halfway between 1/125s and 1/250s, can the camera
>work
>on 1/180s or 1/215s, for instance ?
Yes. There have been previous discussions of this on the list. You
are right. I could not find where Olympus mentioned it in the small
collection of printed stuff I have.
>
> When I have buy my first OM 4 (1987) I have check this matter and the
>slides
>are always sub or over exposed. I work always on Manual mode, so on that
>time I have forget this matter. Some days ago I have tested my OM 4 camera
>one more time shooting on Auto mode with the bars halfway between 125 and
>250 and shooting the same picture on Manual mode with ex. exposure. The
>slide on Manual mode has perfect exposure and the slide on Auto mode is 1/2
>stop sub exposed.
There is probably something else going on. The manual setting is
based on the electronic calculation of the light transmitted through
the first mirror and reflected by the second mirror onto the meter
cell on the floor of the mirror compartment. The automatic
calculation is based mostly on the reflection of light from the
pattern printed on the1st shutter curtain and from the film base onto
the same meter cell depending on the shutter speed. Olympus in the
owner's handbook says the automatic "off the film" metering system
works expecially well_if the frame is evenly illuminated_.
I suspect the difference is not due to any malfunction but in the
difference between your careful manual metering that is tailored to
your subject, and the inflexibility of the automatic system,
especially since you say that the exposure difference may go in
either direction. If it was consistently over or under exposed in
automatic and more than a 1/2 stop, then there might be a malfunction
that needs repair.
My thoughts, but no expert.
Winsor
--
Winsor Crosby
Long Beach, California
.
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