Ajai,
You must have film in the camera for the TTL-OTF auto-exposure system to
function correctly. What you see in the viewfinder comes from one metering
circuit in the prism and it tells you what to expect. Actual exposure
control occurs *during* exposure by measuring light reflecting from the
film. If there's no film in the camera, it's measuring the light being
reflected by the film pressure plate mounted on the camera back, which is
much less reflective than film. This *will* cause significantly longer
shutter speeds compared to what the viewfinder meter shows. Loading the
camera with a "test roll" of film should cure this . . . as I believe you
have already discovered. BTW, for shutter speeds 1/60th and faster, the
curtains also have a white dot pattern that approximates the reflectance of
film.
I recommend avoiding alkaline batteries. They do not last long in OM
camera bodies due to their voltage falloff that starts at about
half-life. This is inherent to alkaline batteries. Even though the
battery box and owner's manual calls for SR44 cells, I use #357 silver
oxide watch batteries. They're essentially the same (#357 = SR44W) and
often easier to find than silver oxide camera batteries. The slightly
different characteristics of the #357 watch battery also seem to make them
last longer in the OM SLR's. Other alternatives include #303 watch cells
and MS76 (Duracell), EPX76 (Eveready), or V76PX (Varta). All of these are
silver-oxide.
With an OM-2n, remember to turn it OFF when it's not being used. Otherwise
the meter circuits will remain powered up and drain the batteries.
-- John
At 10:46 PM 6/8/03, Ajai 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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