OM-1 Replacement Battery

Hi all,

I'm going on a faraway trip soon. I plan to use my Canon Elan during the day, and my OM-1 for piggybacking and prime focus at night. I figured, why not get a battery for the OM-1 so I can use the meter during the day if it becomes necessary or I just want another camera.

Just what battery goes in there? I understand you cannot buy the original battery. And I do not know what it was, anyway.

I have tried a 625 and a 357. Both give me the same readings. And they give me the same readings on both my OM-1 bodies. But the readings do not match the Canon--whose meter I know is correct.

If I cannot find a replacement batery, can I just adjust the film speed dial on the OM-1 to make the needle match the Canon reading, and thereby fool the meter, even if it does not have the correct battery?

Alex

I can't remember the model #, but I went to Walmart and used their battery locator. It pointed me to a Kodak 2.6V I think... may wanna try Walmart?!

The OM-1 was designed to use a PX-625 mercury battery which put out exactly 1.35 volts. In fact earlier cameras like the OM-1 relied on the extremely stable voltage of the mercury cell for an accurate reading. Mercury cells were outlawed years ago due to environmental concerns, leaving silver oxide, zinc air, and alkaline batteries as options for these cameras.
Unfortunately silver oxides are 1.55 volts, zinc air cells are 1.4 volts, and alkalines are supposed to be 1.5 volts but drop rapidly over time. Therefore, none of these will give a reading as accurate as one of the original mercury cell. Wein has come up with a solution that uses a zinc air cell that is supposedly somehow reduced to the proper 1.35 volts, but I have heard varying reports of success (some claim up to one stop exposure error with this cell in the OM-1)
The other option is to use an MR9 microcircuit voltage reducing battery adapter (preferably with a silver oxide cell). It is expensive though, but it has the advantage that you can find the 1.55 volt S-76 batteries that go in it in a lot of places - like walmart :-)

link to MR9 adapter: http://www.classic-cameras.com/MR-9.htm

link to Wein PX-625 replacement:
http://www.adoramaphoto.com/catalog.tpl?op=details&sid=10368725418735479&sku=BYPX625W

Clear Skies,

Joplin