Canonet Brothers: Have You Tried The Wein 1.35 V Battery ?

R

ruben

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Hi Folks,
My 2 Canonets consistently byass to overexposure with the 1.5 V EPX625G battery. The byass is around 1 and half stop. As one of the pair is intended for ISO 200, then there is no problem to byass the camera ISO dial for compensation, setting it between 400 and 800. Fine and cheap.

But the other GIII is intended for ISO 800. I tryied to calibrate the camera exposure meter, without any change at all. Therefore my last hope is the Wein 1.35V battery. Expensive but affordable in case it doesn't byass the Canonet exposure meter.

Has any of you tried this battery and can comfirm it didn't byass his/her camera readings ?

Thanks,
Ruben
 
this type of battery was in the traveling canonet. Lasted 4 - 5 months if i remember correctly.
It works fine.
But there are cheaper options. Hearing aid batteries are the same voltage and quite cheaper. Here in NL one can find some in pharmacies and general drugstores, as well as handyman-stores, and of course the hearing aid specialized shops.
Pick the largest size available and fill up the rest of the space to assure good electric contact but no short.
And be sure to insert it with the correct polarity.
 
Last time I looked, the 1.35v Wein cell was $4.50 at B&H ... I assume that's the right one. Even with postage, for a life of maybe several months, that's less than a roll of film plus processing.
 
greyhoundman said:
How bizarre. I adjust Canonet meters all the time without trouble.

If you are expecting the meter to be perfectly accurate at every F stop, then you will be very disappointed.

Bizarre ? If my un-ability to calibrate the meter sounds bizarre to you Dave, an akcnowledged repairman, whom I myself am sending cameras to repair/overhaul, I cannot but take your word as a nice compliment to me.

And now for the details:
a) Perhaps I have not identified the right screw. The one I turned lies parallel to the camera top or bottom by the area pointed by Rick Olesson page (http://rick_oleson.tripod.com/index-30.html), i, e, its head is quite hard to reach, and is very close to a bluish wire quite tensed, i.e. with very few room to displace aside.

b) After turning counter-clockwise the screw by a full turn, and clockwise a quarter of turn, the needle showed the same exposure. As by most of the tryials I could not twist the screw with a screw-driver, given the hard location, I had to use a kind of thin plyers, resulting in some damage to the head of the screw. It is still turnable, but at that point I backed off.

c) The unsuccesfull calibration was performed with the camera asa dial set to 800, metering a dark area reading with my Sekonic f/4 and 1/4 of second, and at a brighter area reading with my Sekonic 1 and half stop more light. The Canonet meter was consequent at both situations, one and half stop below the Sekonic, i.e. requesting wider apertures.

Any further commentary will be most welcome, as our issue is solving a technical problem.

Cheers,
Ruben
 
Pherdinand said:
........... Hearing aid batteries are the same voltage and quite cheaper.............Pick the largest size available and fill up the rest of the space to assure good electric contact but no short...........

Well, after some research at eBay and related sites, the corresponding size seems to be the battery called 675, with some additional letter according to the manufacturer.

The difference in price is amazing. They are cheaper even than the common EPX625, by two thirds or even more, according to amount of batteries you order.

They are labeled Zinc Air, but.......... 1.4V

Since you have used them, and since price is small, I think they deserve a trial.

Cheers,
Ruben
 
Last edited by a moderator:
Well, uh, I don't think I'm a "brother", but I'll answer anyway. 🙂 🙂

Theoretically (if I remember my electrical theory properly) the higher voltage battery should make the meter circuit "hotter", meaning more current for a given resistance, meaning the meter will move more for a given light level, thus calling for less exposure or tending to underexposure, at least at the bright end of the scale.

This was confirmed in the "before" step of my GIII recalibration last summer, where the unmodified GIII consistently underexposed a stop or so, compared to the Pentax (my "lab standard") when metering a scene out the rear bedroom window in daylight.

I'm getting ready to send in a write-up of the complete recalibration process for Kim to post in a semi-permanent place, but on the first attempt, I was able to get closer to where I wanted to be with just an electrical adjustment, which affects the high (bright) end more than the low end. On the second attempt, I was able to do a mechanical adjustment to get the low end where it was supposed to be, and then an electrical adjustment on the high end to get the thing to agree well within a half stop of the Pentax for both bright and dim lights.
 
I've used the Wien cell in more than one camera, and it has lasted more than a year in both. It appears to do the job great, and I have had no problem with auto exposure. I would recommend it over meter adjustment, but that's just because I am a "cheap fix first" kind of guy 🙂

It's hardly "expensive" as batteries go, IMHO.
 
If you are handy and the camera is low current then you can solder in a Shockey diode, like the proprietary adopters use. This drops the 1.5v from a silver oxide cell close to the Hg cell voltage.

There are detailed instructions for an OM1 posted somewhere.

Then all you need is an O ring to centre the smaller diameter cell.

Noel
 
The "Schockey" diode is probably a Schottky diode. And the voltage drop from those is not constant, but depends on the current through the metering circuit, so whether the diode hack works is very much dependent on the electrical setup of the circuitry.
 
I use the 1.4v zinc air hearing aid batteries for all my RFs except the Yashica, it works very well. The only inconvenience is that I have to either live with the short battery life, or keep replacing/removing the tape each time I take out and use a camera.
 
Kat said:
I use the 1.4v zinc air hearing aid batteries for all my RFs except the Yashica, it works very well. The only inconvenience is that I have to either live with the short battery life, or keep replacing/removing the tape each time I take out and use a camera.


Thank you for sharing your experence.

a) Could you elaborate a bit about "the short battery life" ?

b) No byassed exposure readings ?

c) Could you comfirm the size is "675" ?

Thank you
Ruben
 
I use Wein

I use Wein

mike goldberg said:
Ruben,
I'm using the Wein 1.35 v battery in my OM-1.
It works fine and checks out fairly close with
the Gossen Luna Pro.
Cheers, mike

Just the opposite: I have 2 Wein batteries in my Gossen Luna Pro and it checks out exactly against my batteryless Weston Master V and 2 M5s loaded with mercury cells. I also put my trusty Radio Shack multimeter on the Weins and they check out at 1.35v.
 
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