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Re: [OM] Spot-metering madness

Subject: Re: [OM] Spot-metering madness
From: Moose <olymoose@xxxxxxxxxxxxx>
Date: Thu, 13 Feb 2003 18:30:38 -0800
That can't be right. I don't know how the spot meter is supposed to be adjusted, but here either spot or average is clearly out of adjustment if the testing methodology is near correct, i.e. lighting is actually even. The fact that the error is there with 50mm standard lenses indicates it isn't just the 'angle of incoming rays' effect. The average error over all those lenses from 14-300mm is 2/3 of a stop. If the the metering that is off were adjusted by 2/3 stop, the average error would be about zero and only 5 lenses would be out by more than about 1/3 stop, certainly a better situation than the current one.

Carlos,
Your comparison is made in such a way that it seems to assume that the spot meter is wrong. I don't see where that is necesarily the case, it could be either. If you know or can determine through bracketed tests with slide film, which one is off, you could, at least in the short run, simply adjust the exposure compensation dial by 2/3 stop when switching Modes. That would put you close enough that you would be assured of acceptable exposures with most of your lenses.

Moose

John Hermanson wrote:

...get used to it.........
________________________________
----- Original Message -----
From: "Carlos J. Santisteban Salinas" <cjss@xxxxxxxxxxxxx>

Hi, all.

A while ago I saw on the list a discussion about the (lack of) accuracy of
the OM-4's spot meter with lenses other than the 50mm... but I'm afraid
the
thing is worse than expected!

I tried all my glass while metering on a white sheet of paper, evenly lit
by a relatively distant lamp, and compared the average vs. spot readouts.
The spot mode *always* indicated a slower exposure, but the offset was
related to each particular lens. Here are the results:

Sigma 14/3.5:    -0.7 (I mean -2/3 EV)
Sigma 16/2.8***: -0.7>>>>>>>>>>>>>>





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