I have just bought a Canonette QL19 and have a couple of problems:

1. I cant work out what battery I need as a replacement or rather cannot find one that matches the one in the manual. I thought this camera along with all the canonette series used a mercury battery now replaced by the alkaline PX625 however the battery in my camera is 15.5mm wide and 16.5 mm high and has PC1A alkaline cell stamped on it. I cant find a battery matching this description so i was ondering if anyone could point me in the right direction as to what battery I need to get a replacement is needed. Also meter is about 2 stops out so whats a good solution for this baatery?

2: I set the camera to Bulb held the shutter release down and looked through the back of the camera to chech the aperture is stopping down correctly. However when the shuuter is open the hole stays the same size (approx 3-4mm) no matter what the aperture I set (From F1.9 to F16).
Does this mean the apertue is not stopping down properly or is the hle iam seeing not the aperture? If it is faulty is it worth paying to be repaired or is it something I could do myself?

A few questions there but I would grateful for any advice as I am new to using old cameras.Also anyone know of other forums that may be more suitable for begginers queries as this forum seems to be more for people wanting to fix their cameras and i dont want to keep bothering people with my facile problems! Thanks anyway

By Winfried on Wednesday, October 09, 2002 - 02:11 pm:

1. The only Canonet QL19 I ever hold in my hands was powered by a PX625 mercury cell. I don't know whether there were other models with different battery sizes. The PX640 mercury cells had same diameter but different length, maybe this is the one which would fit. I do not know an alkaline replacement but you can use PX625 size cells plus a few coins, metal washers, springs etc. However, cameras designed for mercury cells will not work correctly with alkaline cells.

2. I think that the aperture blades are somewhat sticky. This happens on some older cameras. The blades must be cleaned similar to the procedure described in Henry's article 'Canonet blade cleaning'. You will have to remove the front lens cell. On the QL19 I have seen first the retainer ring of the name plate ring had to be removed and the name plate ring had to be lifted. Then I had to remove the ring of the front lens element and the lens element itself to get access to two holes inside the lens mount so I could turn it with a spanner tool. However, this is not a job for absolute beginners but for a competent camera repair man it should pose no problems (and should not be too expensive).

By Winfried on Wednesday, October 09, 2002 - 02:13 pm:

BTW I am not the webmaster of this site but I think that ANY questions, may they come from beginners or from camera engineers, are welcome in this forum. In Germany we have a saying 'there are no dumb questions, just dumb answers'. I hope you won't get too much of the latter in this forum.

By Vincent Fairbrother on Wednesday, October 09, 2002 - 10:54 pm:

If this camera originally used a PX640 mercury cell, it was also compatable to use 2 - PX13 mercury cells as replacement which create the same space. If so the only possible replacements for it would be 2 - PX625 batteries in their place, and this would supply 3.1 volts rather than the original 2.7 volts. The metering system can be adjusted internally for this, but the wear characteristics of the akaline batteries according to some will cause eventual exposure error as the batteries get weaker. I have also heard of the Zinc/Air batteries available from Micro Tools at http://www.micro-tools.com/ Expensive, but they supposedly mimic the characteristics of the mercury cells without the environmental hazzard. Good Luck!!! Vincent

By scott clark on Thursday, October 10, 2002 - 05:50 am:

many thanks for the answers they have been very useful. Also thanks to the person welcoming my questions on the forum as I thought they may be out of place! However if my canonette does have sticky aperture blades then I may attempt rectifying it, so I may have some more questions for you! Again many thanks. Scott

By Don L on Thursday, October 10, 2002 - 08:46 am:

I would recommend the Wein zinc-air cell PX625 replacement. It's available at Micro-Tools and most "good" camera shops. It's the proper voltage and current discharge rate like the original mercury batteries. The part # for a single battery is MRB625.

I've heard recommendations to stay away from the 1.5V "625" alkalines due to the extra voltage affecting proper metering, and the different discharge curve.

In a pinch (I've done it.) you can use a 1.4V 675 zinc-air hearing aid battery, and put a rubber o-ring around it to make up for the smaller battery diameter. These batteries are cheap, but last a fraction of the time the Wein 625 does. Like I said, however, in a pinch, they can be found at nearly any pharmacy.

Of course, these older Canons don't even need a battery... ;^)

By Pat Tobin on Thursday, October 10, 2002 - 02:36 pm:

The zinc-air 675 cell, smaller than a 625, can be used in some cell holders with only an O-ring around the outside to keep it centered and in some cases a washer or some other spacer if the cell is not thick enough to reach both contacts.

However, this scheme doesn't work in some cameras, including the Canon EF, Canon QL 17 G-III and probably others. In the EF, (+) contact is made at the rim around the circumference of the cell, not the face. I suspect that might also be the case with other Canon models, but have not tried it. The Wein cell has a pressed-on ring which serves the purpose.

It's all a matter of choice. I prefer a 675 with an adapter I make myself because they are $1 each at almost any drug store, compared with $7 for the Wein cell (that's the price at my usual photo store), available only by mail or from some photo stores. The additional .05 volt of the 675 compared with the 1.35 rating of the Wein cell is insignificant in my opinion.

But like the man says, you pays yer money and you takes yer choice.

By scott clark on Thursday, October 10, 2002 - 04:57 pm:

My canonette's meter seems tobe 2-3 stops out exposure wise compared to my other cameras meters in good light but about half a stop out in low light, is this par for the course when using the 1.5v batteries or is there other problems with the meter?

By Vincent Fairbrother on Thursday, October 10, 2002 - 10:40 pm:

It could have other problems, but it is best to get the proper battery to check it and find out, or power the camera with a variable DC power supply set at 2.7 volts to check it.

By Pat Tobin on Friday, October 11, 2002 - 01:28 am:

Scott - It is correct that a CdS meter error will be greater at high light levels than low. Leon Schoenfeld has plotted this. According to his data, the error due to using 1.5 volts rather than 1.35 is about 1.5 stop at EV-16, which is very bright light. The error is less at lower light levels, and should be the same at multiples of these voltages.

Leon's excellent data can be found at:

http://topconcollection.home.att.net/page32.html

His data is for a Topcon camera, but the meter circuit looks typical; I would expect his data to apply to most CdS meter systems.

Does your meter read high on 1.5 volt cells? If so, my guess is that it needs calibrating. If it reads low, that's a whole new ball game; probably the CdS cell is pooped out.