battery in hi-matic to trick meter?

[imfagent449]

I have recently become interested in photography and I like the pictures from the minolta hi-matic. I have purchased one but I have not yet used it. I tend to shoot in relatively low light and I don't like using a flash. I was wondering if anyone has any experience in installing batteries into a hi-matic e so that they can use 800 speed film. I have read a number of differing accounts on the internet. Some say that it will always have the correct exposure regardless of the batteries and others say that you may need to adjust the film speed for particular battery combinations. I would appreciate any help.

 

[Ducky]

Bump.
I assume the difference between 1.5 and 1.35 volts cannot be ignored in the delicate meters. Is there any chart or advice about adjusting film speed on these auto RFs to compensate for the difference?
My hi-matic f doesn't tell me what it's shooting. My Canonet has a meter showing shutter speed but it goes off the meter on a normally bright day if I set the asa at the rateing of the film in the camera. I shot 100 speed @ asa25 to compensate. I'll experiment but maybe some advice would help.
Thanks.

 

[btgc]

Some say that 1.5V in 35RC works just right. I haven't used any Hi-matic...have you yours [with battery, I mean] ? Maybe it's not that bad?
I'd try soldering Schottky diode to lower voltage, but that's only opinion, not truth.

 

[feenej]

I use a 1.4 volt hearing aid battery in my HiMatic 7Sii and it matches the meter in my Bessa R. The hearing aid batteries are dirt cheap, and I can get them at the grocery store.

 

[Papa Smurf]

You can't fool Mother Nature!

You can't fool Mother Nature!

It has been my experience that attempting to operate an electronic device with a supply voltage out side of its design parameters is begging for problems. Some meters have coils that can be re-calibrated to a different voltage. That is probably the only condition that will give consistently accurate exposure readings. Otherwise, adjusting the "zero" point will give somewhat close readings over a narrow range of some portion of the meters EV range, but over the entire range! 🙁 The same thing as a selenium cell that has gotten tired.

What you need to find out is if your camera is one of the very few that the manufacturer went to the expense of building into it a voltage regulator. There are several sites that give solutions to mismatched battery/cameras. Go to Butkus's site and there is a link to one of these references. I believe that it tells which cameras were/are tolerant and which ones are not.

The idea of the Schlottky diode is good when there is current draw, but what happens when there is no current draw? The 1.55v just sets there pushing on the meter or other electronics. Can they stand up to the over-voltage over long periods of time? If it is a mechanical switch, probably, but what if it is an electronic "switch"? 🙁

I have the same problem with my two Gossen Luna Pro light meters. In one I use an adapter and in the other I use air-zinc cells. Nothing like keeping ones options open.🙂

 

[Eugen Mezei]

1. Guys, make your life easy: Drop me an email and I sold you fresh mercury batteries in the quantity you need. They are still produced in Asia, I have them from GP/Silva.
I don't sell them at high prices as I am convinced I will not get rich out of this. But I will be happy if some of those fine 50, 60 and early 70s cameras would be in use again for the next one or two decades.
(Btw, btgc you sit in Japan, am I right?)

2. The problem is not the voltage difference, it is the different discharge characteristics of mercury and alkaline/silveroxyde/lithium batteries. It is no possibility to recalibrate!

3. Some cameras have built in a voltage regulator. (More correctly it is a voltage compensator, a Wheatstone bridge.) Often the manual of these state you need the mercury types, but I think this was just for easyness when these batteries were avaible and they were known to the camera shops.
If your camera has a battery check by meaning of a light you can be pretty shure it has no voltage compensator. Practically mercury batteries have a discharge curve of having voltage or having 0 voltage. (Constant voltage on the entire life of the battery and a sudden drop to 0 at the life end of it.) So a bulb is perfect for this two states, it indicates burning or not burning, between values are not necessary.

Eugen

 

[Eugen Mezei]

As regarding to make the Hi-Matic sensitive as up as ASA 800 I also thought about it. (Would make the Hi-Matics perfect cameras for photographing in theatres for me.) Maybe the hole over the lightmeter sensor could be made bigger. Calculations and experimenting of about how much bigger will be necessary. Anyone volunteering to sacrifice his Hi-Matic?
Ofcourse with this solution you will not be to use ASA 25, but who cares?

Eugen

 

[Ducky]

I processed a roll from the hi-matic with asa set @ 100 for 100 speed film and exposure was good. I processed a roll from my Canonet, half with the asa set @ film speed and half two stops down. Slight under exposure when set @ film speed, overexposed when two stops down. I think I'll just not worry about it and set @ film speed. I also think I'll get the 1.4 hearing aid batteries and use them. Everything else is too technical for me.
Thanks, all very helpful.

 

[40oz]

A Wein cell battery is designed to replace mercury batteries, is available in sizes to fit, and isn't expensive, just harder to find than hearing aid batteries. That's what I use in my Canonet and Minolta SLR. I've been quite happy with the life of the battery as well.

 

[burple]

I have a Hi-Matic 7, 9, and 11. I use 1.5v silver oxide batteries and I have tested the meters in all three cameras against the meter in my Sony A200.

I find that the extra voltage of the 1.5v batteries yields a 2/3 stop underexposure. This is very consistent across all three cameras and in varying light levels. So I set my Minoltas to +2/3 (e.g., one click stop above 200 for 400 speed film), with great results. The meters of all three Minoltas exactly agree with the meter in my A200 (using a lens with an equivalent angle of view) in any light.