Canon FTbn voltage conversion or adapter

[Roger Hicks]

For the record, we went through a long thread about these voltage adapters here:
http://rangefinderforum.com/forums/showthread.php?t=143181&highlight=pratedthai

For the Leica MR-4 meter, I have a controversy. Don Goldberg feels that the MR-4 can be adjusted to work with the 1.5V silver cells, and makes the adjustment.

Gus Lazzari firmly believes that the linearity may be affected, so he suggests that you use the Pratedthai adapter on his serviced MR-4s.

I've got several MR-4, serviced by both Don and Gus. So far they all seem accurate.

Dear Robert,

Thanks again. Is this adjustment internal (and if so where) or can you just do it on the ASA scale?

Cheers,

R.

 

[expwmbat]

I use the 675 hearing aid battery in my F-1, and it seems to work just fine.

 

[Robert Lai]

Dear Roger,
The adjustment to accommodate 1.5V is done internally by Don. I'm not privy to what he actually does to make the adjustment. You set the normal ASA as per your film speed.

The test I did for the pratedthai comparison was with an MR-4 that had been serviced by Gus, and it required the 1.35V power source.

 

[Steve Bellayr]

Look at this way: If you do the conversion you will have fixed the problem on one camera. If you go with the adapter you can use it on additional cameras.

 

[sevo]

Look at this way: If you do the conversion you will have fixed the problem on one camera. If you go with the adapter you can use it on additional cameras.

... or you will always have to wonder where you last put the adapter!

 

[punkzter]

If I decided to do the conversion, what is the recommended battery? The new mr9 batteries are alkaline.

Would the recommended path be a 386 with a non-voltage altering adapter? Is there a favorite adapter of this type?

 

[Robert Lai]

If you want just a battery holder to fit the battery chamber, then nobbysparrow in Japan (that's his ebay name) sells two of them for $12. It won't convert the battery voltage at all, just holds the battery. That's what I use for cameras that have had the voltage adjusted to take 1.5V.

Even in them, I use silver oxide cells, as they have a flat discharge curve. Alkaline cells will continue to run down in voltage as they drain, so who knows what voltage they are putting out today?

 

[Timmyjoe]

Go with the MR-9 Schottky diode adapter and the Duracell 301/386.
It is the best way by far, and that combination provides for a very long-lasting metering setup. (Long battery life as opposed to a smaller battery.)

This is what I use in my old Canon (F-1n, TX) cameras, and it works great. The silver oxide 301/386 batteries have a "discharge/per life" characteristic curve similar to the mercury oxide batteries that these cameras were designed for. Unlike alkaline batteries.

Best,
-Tim

 

[Roger Hicks]

Dear Roger,
The adjustment to accommodate 1.5V is done internally by Don. I'm not privy to what he actually does to make the adjustment. You set the normal ASA as per your film speed.

The test I did for the pratedthai comparison was with an MR-4 that had been serviced by Gus, and it required the 1.35V power source.

Dear Robert,

Thanks.

Cheers,

R.