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Jefflang
Tinkerer
Username: Jefflang
Post Number: 1
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 02, 2007 - 11:00 am: | 
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Hi,
just got my OM10 loaded with two new SR44's and it seems that all speeds are the same despite changing aperture. Also, same speed when using
Bulb setting. Any ideas? |
Loosecanon
Tinkerer
Username: Loosecanon
Post Number: 14
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 12, 2007 - 02:04 pm: |
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The OM10 is an all automatic exposure camera unless you have the manual adapter installed. Changing the aperture setting on the lens without the adapter probably will not effect the shutter speed. As for the bulb setting situation, I will defer to those more familiar with the OM10... |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 269
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 12, 2007 - 08:28 pm: |
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On the contrary, changing the aperture setting on the lens should very much affect the shutter speed: for every stop closed down the shutter speed should run one stop slower. Bulb, of course, should behave as Bulb; staying open as long as the button is held down.
The manual adapter consists of an array of resistors through which a circuit is closed through a connector plug that is inserted into the front of the camera to the left of the lens mount.... a given resistance equating to a corresponding speed. If the camera seems to be stuck on a single speed when set to AUTO without the adapter attached, I would look for a short in the board where the manual adapter attaches.
I will add here the usual caveat when assessing AUTO speeds on any OM camera that the meter is trying to read light reflecting off the film, and that without film the meter, trying to read off the black pressure plate, will deliver significantly slow speeds. This does not seem to relate to your complaint. However, if you try to test the speeds with the back OPEN, the meter reads the ambient light coming through the open back, and in this case you will get a very fast speed, probably 1/1000, regardless of the aperture set. Even in this case, though, B should still work normally. |
Alex
Tinkerer
Username: Alex
Post Number: 33
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 13, 2007 - 04:37 am: |
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Rick, I understand your explanation about metering off the film, but this suggests that any metering information given by the camera in the viewfinder before the exposure is actually made is inaccurate, so there would be no way of recording in a notebook, as I habitually do, what the exposure was at the instant of taking the photograph. Is this the case, or have I misunderstood something? |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 270
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 13, 2007 - 09:57 am: |
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that is true, the meter in the finder is totally separate from the actual autoexposure system... different light cells, different circuits, everything but the battery. The finder display should give you a good indication of the speed you're going to get, but not necessarily: if lighting conditions change during the exposure, the AE system will automatically compensate for it, and if there's a problem in one of the 2 metering systems the other one will probably not be affected by it. |
Alex
Tinkerer
Username: Alex
Post Number: 34
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 13, 2007 - 12:18 pm: |
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Ah, that makes sense. Isn't it strange how it only becomes patently obvious after someone else has explained it to you! |
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