Canonet battery strangeness

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fretbuzzard

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Hello all, this is my first post.

I just received a Canonet G-III QL17 from a reputable used dealer. I had read the threads here about merc battery replacements, and had decided on the C.R.I.S. adapter so that I can use silver 386 cells. Here's the strangeness: when the camera arrived it had a 625A alkaline cell in it. The battery check light and the meter seemed to be working, but I had read about faulty meter readings using the 625A cell, so I switched over to the adapter+386. But now the check battery light does NOT work, though the meter still does (giving a slightly different metering than the 625A).

The (-) contact has a bit of oxidation on it, but nothing too out of the ordinary.

So I guess my question (apart from what's going on here!) is whether I can assume that this camera had been adjusted to take the higher 625A voltage by its previous owner (hence the battery check light only coming on with the higher voltage 625A and not with the "proper" voltage 386)? Any thoughts?

Ted
 
I believe I have read there is a diode in the adapter which does not pass enough current to work the battery check light, but does allow enough to operate the meter.

I did some experiments myself this past Saturday with my own GIII 17, a fresh 625A, and a fresh Wein cell. IN bright daylight, the camera opened about a full stop more with the Wein cell than with the 625A. Indoors, in more subdued light, the difference was less. That confirmed what I've read here also, that the difference is not linear and is more pronounced in brighter light.

Another thing I've read here is that the discharge curve of the alkaline 625A battery is different from that of the mercury or wein cell- less "flat". That could mean a 625A could read spot-on at some point in its life, and be off one way when new and off the other way when it's old. Bottom line is that the 625A might be good enough for many of us, but can't actually be calibrated perfectly.

Ed
 
This is normal. You lose battery check with any diode fix but the meter will operate properly.
I use a homemade adapter with my Canonet and the meter readings are consistently accurate even though I don't have battery check.
 
Thanks guys! Now that I have a bit more information I'm doing some more digging on this and other sites. Greyhoundman, I see that you've answered a question like this before, so special thanks for your patience in dealing with a newbie who hasn't figured out how to best seearch the forums yet!

Happy picture making...
 
The adapters that are made by John Neal who is a member here have diodes that are heavy enough duty to cope. They will also work in other high drain cameras that the Kriss adapter doesn't like.

Kim
 
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