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Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 23
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 12, 2009 - 01:13 pm: | 
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I have an old Canon F-1 -- the original model. It takes the now banned PX625 battery. Currently, I'm using a 675 zinc-air hearing aid battery to power the meter, but I would like to convert the camera to use silver-oxide batteries. There are a few ways to do this:
1) Adjust the ASA dial to re-zero the meter. This apparently has its drawbacks due to changing values in the dynamic range?
2) Buy a CHRIS MR-9 adapter. This works well, but at $32-something plus shipping each, I'm cheap enough to look for alternative solutions.
3) Buy a Schottky diode and install in inline in the meter circuit so that a silver oxide battery can be used.
I'm curious about #3. I've found a how-to on the Web for Minolta SRTs, but nothing for the Canon F-1.
Ever done this conversion/update? If so, would you care to explain the procedure?
Thanks,
Michael |
Chiccolini
Tinkerer
Username: Chiccolini
Post Number: 54
Registered: 06-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 12, 2009 - 04:05 pm: |
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On my PX cameras I just use the PX625 battery commonly available which is an alkaline or silver oxide. Only shoot print film and it works out ok anyway.
http://24hourbatteries.com/shop/__a625pxcamera.html is a good place to buy. |
Dragunov
Tinkerer
Username: Dragunov
Post Number: 154
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 12, 2009 - 04:15 pm: |
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doesn't really answer your question, but, I have a FTb, an F-1 (like yours) and a Gossen lunasix lightmeter and I use alkalines (LR 44) in all of 'em. the Canons, you can adjust the ASA, the lunasix needle zero can be adjusted. works fine with slide film. I check often, though... |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 24
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 12, 2009 - 04:20 pm: |
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Well, I plan to be putting a lot of slide film through this camera, so I want the meter as accurate as possible. With a fresh 675 battery, the F-1's meter agrees exactly with my Luna Pro F, which is a meter of known accuracy. I plan to check the voltage drawdown about once a week for starts, and compare the difference in readings between the F-1 and the Gossen as the voltage drops. Sure is a hassle though. Which is why I asked about adding the Schottky diode. |
Jon_goodman
Tinkerer
Username: Jon_goodman
Post Number: 45
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 12, 2009 - 07:35 pm: |
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For a number of reasons, I'm not a fan of the diode approach. I do like the zinc-air cell, though. If you need an adapter to turn the #675 into a clone of the PX-13, please send me an email.
Jon |
Mndean
Tinkerer
Username: Mndean
Post Number: 166
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 12, 2009 - 07:59 pm: |
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I have to agree with Jon. The diode approach works pretty well on some cameras. Others, not so good. Canons I know nothing about how well diodes would work. The 675 zinc-airs seem to work well with everything I've tried them on. Most only need a slight ASA adjustment with slide film (I always match with a known-good hand meter before shooting). |
Glenn
Tinkerer
Username: Glenn
Post Number: 684
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 13, 2009 - 03:53 am: |
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The only F-1 with a diode modification passed through my hands some time ago, being sent to me because the meter system had failed and the owner was stuck for a remedy - restoring the circuit to how Canon designed it got everything back to normal!
I prefer the adapter approach, using the MR-9 (I got a very good bulk discount here in UK) in cameras etc, with Gossen's own adapter in meters requiring same.
I would advise you to at least contact Jon Goodman and see what he has to offer, especially if you are contemplating 'surgery' on the F-1! |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 25
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 13, 2009 - 11:47 am: |
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Thanks for your perspectives, guys. For now, I'll be monitoring the voltage drop on the 675, and see how often it requires a meter adjustment. If it looks as if this will become a tedious process, then I will definitely be considering the best alternatives. |
Mndean
Tinkerer
Username: Mndean
Post Number: 167
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 13, 2009 - 02:00 pm: |
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Use the zinc-air (hearing aid) 675 battery. Its voltage drop characteristics are very similar to mercury, but has a much shorter life. The other difference is that it's 1.4v instead of 1.35v, which can cause some error in metering (the most I've ever gotten was a 1/2 stop error). |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 26
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 13, 2009 - 05:11 pm: |
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That's what I'm using -- the 675. The battery's been in the camera almost a week now, and I checked it just a short while ago. I'd left the meter on since yesterday and was concerned I might have drawn it down, but nope -- 1.39v. And as I mentioned above, the F-1's meter agrees exactly with my Luna Pro F. |
Mndean
Tinkerer
Username: Mndean
Post Number: 168
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 13, 2009 - 08:26 pm: |
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I'd say you're all set, then. When the zinc-air dies, it does so quickly, so you'll notice the metering getting very inaccurate (at least I have). I always keep extras with me just in case. They're small enough to put anywhere. I keep a couple taped to a film can lid in my pocket. |
Verduzcor
Tinkerer
Username: Verduzcor
Post Number: 6
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 02, 2009 - 05:55 pm: |
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Hi, I made the surgery approach, installed a schotky diode in line with the cell cable, under the left bottom plate can unsolder the cable and insert the diode, be careful to make properly polarity oriented, I use silver oxide cell with a rubber O-ring to center into cell chamber.
Tested with negative color film and a light meter as a back to compare readings, very good prints, I’m very happy with success, but plann a test with slides by holidays. |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 46
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 05, 2009 - 04:31 pm: |
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Hey Verduzcor, thanks for the feedback on your installation. I've been using my F-1 for the past couple of months with the 675 and so far it's been good. Please let us know how your setup fares with slide film. |
Lucas
Tinkerer
Username: Lucas
Post Number: 103
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 06, 2009 - 05:18 am: |
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I use 675 hearing aid batteries in almost all my cameras. In a climate that is not very dry they last a long time. My gossen lunasix has been running on two for about 9 months now and the battery check still goes to the ok point. |
