Re: [OM] OM2n

[Chris Barker]

Hi Ajai

Welcome to the List and congratulations on your purchase of a delightful little camera.

Franz Pangerl wrote in "The World of OM Systems", 1977 about  "OM2 Auto-Dynamic Metering Control".  Before you press the shutter release, exposure is measured using the CdS cells in the viewfinder prism housing to give you an idea of the impending exposure.  When the shutter is released, the actual exposure is measured off the film (OTF).  If there is no film in the camera, a special screen is used to provide a sort of typical reflectance of film.  The difference that you have noticed is probably due to light entering the viewfinder from the rear (try shading it with your fingers while you look into the viewfinder) and from the different measuring systems (CdS cells versus the SBCs doing the OTF job).

Chris


On Monday, Jun 9, 2003, at 04:46 Europe/London, ajai krishnan wrote:

>  Hi,
> I have just bought a old OM2n with few lenses. I was a bit confused with the way the meter works. Or rather the way exposure takes place. In the auto mode, in low light condition, the viewfinder information does not match with the actual exposure. i.e, the exposure time (shutterspeed) is much more than the shutter speed shown in the viewfinder. This I have been able to notice only for the low light condition. I posted this question in the 'photo.net' and have got a very helpful reply. That is, I have been experimenting this because there was no film in the camera. I believe there is something called OT-F which will calculate the exposure overriding the viewfinder information. Please any of you could throw some light on this subject. I tried the same experiment with the film inserted and now it is giving more or less the same exposure as per the viewfinder. But still about ! 1 or 1.5 seconds difference in very low light situation. I need another information - is it ok to use LR44 (alkaline)battery for OM2n as Iam unable to get SR44 (silver oxide) batteries. With thanks. Ajai
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C M I Barker
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