Canonet lens needs a cleaning ?

[MattKing]

There are cameras whose metering circuits work with cells whose voltage changes over time - with those cameras, an alkaline battery like an LR44 is suitable, assuming either that the nominal voltage of ~1.55V of the LR44 is suitable, or that the circuit has either been adjusted, or a voltage dropping adapter has been installed. As I understand it, _Brian is telling us that the Canonet QL17 GIII is one of those cameras.
That surprises me, because I was under the impression that the circuitry in that Canonet required a battery that supplied a more consistent voltage - either a higher voltage silver oxide cell, or the lower voltage zinc air substitute for the even more consistent mercury cells.
But I'm prepared to learn.

 

[__Brian]

The "Green Zone" for the battery good indicator on the Canonet QL17l is a full-F-Stop wide on the scale. The same is true of the Minolta H-Matic 9, which also uses the meter needle as a battery check. I prefer the meter being used over the Lamp. Better indicator of condition than just "pass/Fail".

 

[reddesert]

There are cameras whose metering circuits work with cells whose voltage changes over time - with those cameras, an alkaline battery like an LR44 is suitable, assuming either that the nominal voltage of ~1.55V of the LR44 is suitable, or that the circuit has either been adjusted, or a voltage dropping adapter has been installed. As I understand it, _Brian is telling us that the Canonet QL17 GIII is one of those cameras.
That surprises me, because I was under the impression that the circuitry in that Canonet required a battery that supplied a more consistent voltage - either a higher voltage silver oxide cell, or the lower voltage zinc air substitute for the even more consistent mercury cells.
But I'm prepared to learn.

I used a Canonet QL17 G-III as a travel camera with alkaline batteries, for years after mercury batteries went away. I used the PX625A that is shaped like the original battery, and if I didn't have one of those I used the LR44 with a shim (aluminum foil or similar) because the LR44 is a little shorter. On these last small-body generation of Canonets, the battery inserts sideways, so it is real easy to shim. I usually adjusted the ISO setting by about a half stop to compensate. I only shot B&W and color negative film so it was less picky than slides.

My Canonet now has an issue with the meter where the needle stops at f/8, so I haven't been using the meter recently. My point here is that people make a huge deal out of the battery voltage thing when:

1. Many cameras work at least ok by just compensating the ISO, especially if you shoot film with latitude and use your brain when metering, since it isn't TTL, isn't fancy matrix metering, can be fooled by backlighting or bright sky like any meter, etc.

2. The working condition of the meter in a 40+ year old camera is at least as important as the battery voltage. If you don't at least test the meter (try a typical outdoor scene and an indoor scene), you don't know what you are going to get, regardless of battery.

 

[MattKing]

For clarity, the reason that alkaline batteries don't work in some cameras is that their voltage changes quite a bit as they are used. With some cameras, this means that the meter is accurate during part of the battery's life, but becomes less and less accurate as time goes on.
In that situation, with that type of camera, I prefer not to have any battery in the camera.
As I posted earlier, if the meter circuit in this model of Canonet is tolerant of changes in voltage through the life of the alkaline battery, then great!

 

[__Brian]

One of my PX625 batteries has survived into the 21st century and registers with good voltage on my Fluke 27 meter that I pulled out of a trash can at work. Seems the LCD panel was misaligned and the numbers no longer registered. Took that apart and fixed it. My Canonet- took it apart years ago and fixed the short on the battery compartment. It works too.

I just used the PX625 and a new PX625a n the camera- about 1/3rd of stop. No difference in the real world shooting film. If you convert your Canonet to Digital, maybe means blowing the highlights a little sooner. 20 years ago I was using a Nikon N8008s at my Daughter's school and another Dad went to lecture me on Digital. Told him "THIS camera used to BE digital. I converted it to film!" It was from a Kodak DCS200c.

If your camera has a built-in battery check, and the QL17l and GIII do- use it as a guide for an alkaline battery discharging to unusable voltage. Most stay above 1.35v until the bitter end.