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Ken
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 20, 2005 - 08:20 am: | 
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Hi
After my last message I looked at the OM2 in more detail. It does have a fault. Changing the f stop (or moving the lever in the camera body) does not affect the exposure meter reading in either auto or manual mode. The reading does change with varying light levels, and in manual mode with changing exposure time. By comparing to my OM1, the meter on the OM2 registers the f stop as f8. The "correct" exposure readings I mentioned before were pure coincidence.
I have shot two films. One manual with a wide variety of f stop / speed ratings with the exposures determined by the OM1. All pictures were perfectly ok. The other auto-mode under varying light conditions. Every f stop (f16 to f1.4) was used several times. All perfectly exposed.
As automatic mode is fine, I have no intention of trying to fix the camera, but out of interest does anyone have an idea what the cause of the problem is?
Rick! Thanks for the info on the tests. The long auto exposure lasted about 70 secs. The test with the tv was interesting. I didn't see the diagonal on every exposure. Sometimes it was quite obvious, somtimes it just seemed to be at the edge of the shutter. Is that normal?
I also found the info on the batteries for the OM1. Mine still contains a PX625 measuring 1.35V. I can't remember when I put it in, it must be quite a few years. Although I knew about mercury batteries being withdrawn, I wasn't aware of all the issues about the voltages of the replacements. Now I know! Thanks!
Ken |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 20, 2005 - 11:23 am: |
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Hi Ken:
On the early OM1 at least, the aperture ring is coupled to the meter by a cord that goes over a few pulleys from the ring (actually, from a ring just inside the lens mount which is operated by a tab on the back of the lens) to the galvanometer. I don't recall ever opening up this part of the OM2, but I do have a manual at home to look at. In any case, it sounds like the connection from the aperture ring to the meter has become jammed or broken.
None of this will affect the AUTO mode, because in AUTO the meter waits until the lens has stopped down and then reads the light actually reaching the film, regardless of what the viewfinder meter (or even the lens aperture setting) may indicate.
The diagonal stripes in the shutter test will be completely random in location - it just depends on where the TV scan happens to be at the instant the shutter begins to open. Keep trying, and occasionally one will come up where it's easy to see.
rick : ) = |
ken
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 21, 2005 - 05:58 am: |
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Rick
Thanks! I wondered if the random stripes was a random fault! Makes sense now.
You mentioned the manual at home. Are you familiar with Mark Dapoz's "Olympus Hardware Resource Page"? He has all the manuals for the OM cameras and lenses on-line, free to download for personal use.
http://olympus.dementia.org/Hardware/
I don't have the facilitiies to dismantle, fix and re-assemble an OM camera, but it was interesting to look at the diagrams.
Regards
Ken |
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