625 to LR44 battery spacer for OM-1?

I've just picked up an OM-2n. They used the same body as the OM-1, so the battery compartment is sized for a 625 mercury cell; but there's a crescent-shaped spacer in it so that two LR44 cells can be used. I have an OM-1n. I've had it modified to use a 625 silver oxide cell (1.5v), and had the meter calibrated. The 625 cells are a little harder to find than the LR44s. Is there a crescent-shaped adapter I can buy so that I can use one LR44 cell in my OM-1n?

I don't remember the exact dimensions off hand, but I just went to the hardware store and got a short length of plastic tubing whose inside diameter would fit nicely around an LR44/357 and outside diameter would fit neatly inside the battery compartment. Just cut it to the width you need. Make spares.

FWIW, I have a type 675(same size as an LR44/SR76 cell) in the battery compartment of my OM-1 and it works fine with as accurate of a meter as you can expect from a CdS cell/galvanometer. I did the same with my Pen FT.

 

I don't have a spacer-I just dropped the battery in. I've been successful in doing this with a bunch of different cameras sized for 625s(including various Canons going back to the mid-2000s for me), and most are fine. I seem to only have issues in cameras that need two stacked cells like some of the Nikon F meters, but even a lot of non-Nikon cameras like my Konica Autoreflex TC are fine.

FWIW, I have a type 675(same size as an LR44/SR76 cell) in the battery compartment of my OM-1 and it works fine with as accurate of a meter as you can expect from a CdS cell/galvanometer. I did the same with my Pen FT.

 

I don't have a spacer-I just dropped the battery in. I've been successful in doing this with a bunch of different cameras sized for 625s(including various Canons going back to the mid-2000s for me), and most are fine. I seem to only have issues in cameras that need two stacked cells like some of the Nikon F meters, but even a lot of non-Nikon cameras like my Konica Autoreflex TC are fine.

 

Yes, I've done it without the spacer too and it seems to work fine.

FWIW, I have a type 675(same size as an LR44/SR76 cell) in the battery compartment of my OM-1

 

The 625 has a larger diameter than the LR44.

The 675 zinc-air hearing aid battery is the same diameter as the LR44, but just slightly thicker. I've been using them with an o-ring spacer instead of buying 625 Wein cells, and the voltage (1.4v) is close enough to work OK.

Zinc-airs are fine, they just don't last very long. If you have some soldering skills, there's enough room outside the battery holder on an OM-1 to install a Schottky diode which will drop the voltage of a modern 1.5 volt battery to the 1.35 volts expected by the meter.

 

A very nice youtube video details the procedure:

 

 

The "fix old camera" series of videos is awesome FWIW.

Zinc-airs are fine, they just don't last very long.

 

I often hear that, but at the same time I often see a surprisingly long life out of them.

 

As an example, I've had the same battery in my Pen FT since October, and it continues to work fine.

 

Over many years of using them, I've consistently seen 6 months-1 year from them. To be fair, in my experience it depends to some degree on humidity-I've had batteries die in 3 months when the camera was used outside on a frequent basis in the summer. The 1 year seems to be on cameras that mostly sit on a shelf and never go outside.

I often hear that, but at the same time I often see a surprisingly long life out of them.

 

As an example, I've had the same battery in my Pen FT since October, and it continues to work fine.

 

Over many years of using them, I've consistently seen 6 months-1 year from them. To be fair, in my experience it depends to some degree on humidity-I've had batteries die in 3 months when the camera was used outside on a frequent basis in the summer. The 1 year seems to be on cameras that mostly sit on a shelf and never go outside.

 

I've had them last several months but that seems to be the exception for me. Never made the connection to humidity but you might be right. In my experience I'm more surprised than not if a zinc-air battery still works in a camera that's been sitting a couple of months.

 

I've had 3 OM-1n cameras and added the diode to the first two. I haven't done the 3rd yet but probably will. I've also had two RC-35s, a Canonet QL17 Giii, and a Yashica TLR that I've used zinc-air batteries in.

 

Thankfully, just about as many cameras get sold as get bought and my goal is to end up with one medium format camera, an SLR, and a compact rangefinder. My hope with the SLR is that I can grab it on a moment's notice and expect it to work without a lot of putzing. Same with the rangefinder. The medium format camera is more of a special purpose thing and I've gotten to the point with the Yashica that I don't even bother with the battery. The on-board meter isn't so great anyway so I'll use an external meter with that.

The 675 zinc-air hearing aid battery is the same diameter as the LR44, but just slightly thicker.

 

My 625 cells have a larger diameter than my LR44 cels.

 

My 625 cells have a larger diameter than my LR44 cels

 

I was talking about the 675 battery, not the 625 battery you are showing. The 675 zinc-air is on the left, and the LR44 is on the right.

 

Edited June 7, 2019 by m42dave

And here's the 675 with an O-ring around it.

 

Ah. My OM-1 takes a 625.

My point was that I use 675s in my OM-1, Pen-FT, and a whole bunch of other cameras without any sort of spacer. I just let the battery rattle around in the compartment.

 

There are a few cameras where it doesn't work-cameras that take two stacked cells are often touchy, and I've found all forms of the Nikon F metered prism(most take 2 cells, but this is true even the single cell original Photomic) to REALLY need metal-to-metal contact on the side for reliable operation.

 

My OM-1 works fine with just a 675 in the chamber-no o-rings, spacers, or anything else.

My point was that I use 675s in my OM-1, Pen-FT, and a whole bunch of other cameras without any sort of spacer. I just let the battery rattle around in the compartment...

 

My OM-1 works fine with just a 675 in the chamber-no o-rings, spacers, or anything else.

 

OK, I got you. I'll try a 675 in the OM-1 without any mods when the 625 runs out. I was curious tough, because the OM-2n has a crescent-shaped spacer for the LR44s.

OK, I got you. I'll try a 675 in the OM-1 without any mods when the 625 runs out. I was curious tough, because the OM-2n has a crescent-shaped spacer for the LR44s.

The OM-2 was designed to use 2 LR44. It needs the 3V and thus Olympus made the mod of the battery compartment. I guess Olympus tried to save money by not completely design the OM-2 from scratch.