OM 2n- erratic metering on auto

[arnaldo_vargas]

I just purchased a used OM 2n and it seems to be geting accurate readings and shutter

speeds when used on manual but as soon as I switch to AUTO the shutter seems to stay

open for much longer then indicated in the viewfinder. BTW-I am using Ilford Delta film in

the camera. Any ideas as to what might be causing this, and possible fixes.

 

Thanks!

Arnie

[mark_bouquet1]

The standard answer when someone asks this question is to suggest that they put film in the camera. Since OM-2n auto-exposure meters off the film (OTF) and/or shutter curtain, when there's no film the meter is measuring off the pressure plate, which is less reflective than film. Since you do have film in the camera, that answer won't work for you. I don't know Ilford Delta. Could it have a reflectance significantly different than films typically do. One way to test this would be to meter a scene in manual and auto that requires a shutter speed faster than 1/60th sec. If the shutter speeds seem to be the same, you can rule the film out as the source of the problem. This is because at faster shutter speeds, the auto exposure system makes it's exposure determinations off the shutter curtain instead of the film. Thus the film you're using is out of the loop. If you still have a discrepancy between manual and auto at high shutter speeds, I think it's time to have one or both meters calibrated.

[mark_bouquet1]

Correction: I should have said "If the shutter speeds seem to be the same (at high shutter speeds in auto and manual), you can rule the film 'IN' as the cause of the problem.

[j_yee]

The question we need to ask is how do the negatives look? I noticed that my OM-2n gets alot of excess light from the view finder and reads faster than actual.

[grahams]

Arnie - As Mark has said, the indicated reading in the viewfinder may differ from the reading actually used when you fire the shutter - the viewfinder reading is taken from a seperate metering system to that of the actual OTF reading. It is also true that the viewfinder reading will differ greatly if the eyepiece is not covered.

 

I have not been able to detect any great difference in actual readings made with a variety of different film types, nor have I ever heard of this being a factor worth considering. One thing is certain - if there is no film in the camera, the OTF reading will be false. And make sure that you are using SR44 batteries or the equivalent, not LR44.

[arnaldo_vargas]

Thanks to all for the great advice.

By now I have covered all the variables that might be causing the problem. I swiched the

batteries to SR44 (Energizer 357), tried shooting with T-Max instead of the Delta to rule

our reflectance problems. The photos shot on Manual with the Cds meter off the ground

glass have been accurate but all the AUTO shots still give me a black negative as the

shutter stays open for several seconds. I guess I'll juat use it as an OM1 untill I can get the

OTF meter fixed/ calibrated.

[arnaldo_vargas]

I read somwhere that OM2n's sometimes suffered from oil migrating to the shutter

magnet, causing a sticky shutter. What I don't understand is why this would affect the

shutter on AUTO but not on Manual. Could this be the problem? What do you think... any

ideas?

[mark_bouquet1]

If the shutter's sticking, it would do it equally in auto or manual. It's very unlikely that's your problem. Another thing you might check is to be sure that no one put a "bright" focusing screen in your camera, like an Olympus "2" series or a Beattie for example, without adjusting the meter to account for it. If they had, the manual meter would respond to the scene as if it were about 1 stop brighter than it actually is. Auto exposure, however, would be unaffected. If that were the problem you'd be getting accurate exposures in auto, and underexposures in manual, which is the opposite of your problem. Still it might be worth looking at.

 

The real bottom line here is that pretty much all OM-2's are of an age where they need a tuneup by a qualified technician. Even if yours was working flawlessly, there's still the issue of rotting foam inside of the prism housing, which will eventually damage the mirrored coating on the prism. If your camera hasn't had this done, you can trust that it needs it. The good news is that if you like the camera, it's worth the expense. I can personally recommend Camtech at www.zuiko.com.