Leica MR4 meter battery

[gwpics]

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I have just bought a mR4 meter to match my M4-P and I am aware that the PX625 batteries are no longer available. What is the best viable alternative.

Thanks

Gerry

 

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[a.noctilux]

Some ideas, here

[AndreasG]

I made good experience with the above mentioned WEIN Cell in my old Leicameter MR4 (which I also use with a M4-P), only life time is much less compared to the PX625.

[R6M6]

I can also recommend the Wein Cell , I use them with my SL2 and Film CL. Lifetime is much shorter and is not only related to the operation time but also lifetime starts with the first use independent from usage (hope you get what I like to express)

[hilm3]

I have two MR-4 meters. On one, I had the meter adjusted to use a 1.5 battery. On the other, use an adapter that steps down the voltage from 1.5 to 1.35. Both work well and consistent with each other. The adapter is the C.H.R.I.S. MR-9 adapter. Bought one at B&H. Also used it on an M5 I owned for a while. There are other outlets including CHRIS website. Ama*on and E*ay probably.

[Edgar1920]

Hello Gerry

I habe also used the Weincell and was not totally satisfied (not regarding the high price): as it is basically a 675 zinc-air cell presses into a metal ring it is not long enough and I had to add a small cardboard disc to add 0.5mm in order to get reliable contact.

Finally I ended up seeking the nominal dimensions of the PX 625 cell and asked a local turning shop to manufacture a couple of adapters that work very well:

Now I can afford zinc air cells a GoGo. If anybody is interested you can find a set of the adapter and 6 cells here:

https://www.ricardo.ch/kaufen/foto-und-optik/sonstiges/leicameter-mr-mr-4-batterieadapter/v/an1051880190/

Be aware with zinc air cells that they tend to leakage quickly once discharged. I usually keep the blue sealing tab and put it back on the small holes when I do not use the meter. This increases lifetime when not used. And when not using it for a longer period (more than 2-3weeks) I take them out of the Leicameter just to prevent damage due to leakage.

I also tried recalibration on 1.55 silver oxide cells but this may affect accuracy in the top and bottom end of the dial so finally my personal preference is zinc air.

I hope this information is helpful to you.

Best regards,

Frank

 

[edstock]

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Hey if you are in the US head to a company,. they have stores all over, called Batteries and Bulbs. They have Wein batteries, they have batteries for about everything powered by a battery. I bought half a dozen popped one into my MR-4, no problem. Remember these are zinc air batteries, not long life like lithium. I think my battery lasted about six weeks, with only occasional usage. The German batteries in my hearing aids are German zinc air and I get maybe 10 days from them. 

[gwpics]

I think the MR4 was a bad buy. I didn't do enough research into battery life. Added to this the battery door snapped off the first time I tried to put a battery into it. It is still usable with a bit of tape to hold the battery, but far from ideal. I love the M4 as a camera, and can usually guesstimate the exposure pretty much after 60 years of experience. but have also managed to buy an M7 now.

Thanks everybody for your help!

Gerry

[a.noctilux]

I think it was not a BAD buy, but better buys are plenty in the market now.

I have some (five ! not working for different reasons) that I bought over time, and they are now less reliable than they once were.

Once I take one for picture taking, worked and tested when I put a "right" battery in, but in real use, not so reliable.

Now I just use VCmeter II when I need a small one for M-A for example or another modern handheld meter.

 

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Or better yet, keep the meter in one pocket.

[edstock]

I should have added I purchased a new Voighlander VC meter II, which uses LR 44 lithium batteries. I have retired my Leica MR-4 used on my MP-4. It is very accurate and far more practical.

[a.noctilux]

23 minutes ago, edstock said:

I should have added I purchased a new Voighlander VC meter II, which uses LR 44 lithium batteries. I have retired my Leica MR-4 used on my MP-4. It is very accurate and far more practical.

Voigtlander VCMeter II is a very nice modern meter which is very reliable and so small.

In my VCMeter II,

I use 2x 1.5V silver oxide SR44 or alcaline  LR44 .

I don't know that the meter accepts lithium battery which has 3V in most and double the size of LR44/SR44 1.5V

lithium bat. not usable as side by side in VCMeter II.

For me LR44 is always alkaline 1.5V battery after this equivalent LR44 guide

 

 

[jerzy]

main problem in MR, MR4 are the corroded contacts, not always they can be cleaned so that it works reliable. For the batteries - zinc-oxide provide correct voltage (no recalibration needed if battery test will show proper result) but they discharge constantly as soon as a hole is opened. From my experience they last not longer than 2-3 month. Therefore I prefer using alkaline batteries which provide 1,5V. As edgar1920 wrote recalibration alone may lead to wrong measurements therefore reducing the voltage is more accurate way. And this may be achieved in 2 ways: either purchase an adapter with built-in diode reducing voltage, you may use regular LR44 which are not expensive and widely available. Or, what I prefer, insert a diode into circutry of MR (same I am doing for CL) and use modern alkaline 625 which have the same size as PX625. 

Edited April 14, 2019 by jerzy

[AndreasG]

vor 7 Minuten schrieb jerzy:

Or, what I prefer, insert a diode into circutry of MR (same I am doing for CL) and use modern alkaline 625 which have the same size as PX625. 

Could you please explain this process a little more in detail? Any photos, step by step available?

[jerzy]

I will prepare pdf with instruction and photos and post it tomorrow evening 

[Edgar1920]

vor 7 Stunden schrieb jerzy:

main problem in MR, MR4 are the corroded contacts, not always they can be cleaned so that it works reliable. For the batteries - zinc-oxide provide correct voltage (no recalibration needed if battery test will show proper result) but they discharge constantly as soon as a hole is opened. From my experience they last not longer than 2-3 month. Therefore I prefer using alkaline batteries which provide 1,5V. As edgar1920 wrote recalibration alone may lead to wrong measurements therefore reducing the voltage is more accurate way. And this may be achieved in 2 ways: either purchase an adapter with built-in diode reducing voltage, you may use regular LR44 which are not expensive and widely available. Or, what I prefer, insert a diode into circutry of MR (same I am doing for CL) and use modern alkaline 625 which have the same size as PX625. 

Hello Jerzy

I have tried the same on my Gossen Lunasix with average success. One thing to pay attention to is that alcaline batteries (LR44) do not have constant voltage during lifetime. New the have more than 1.5V going down to 1.3V or less. So if you calibrate I suggest to do so for silver oxyde cells (SR44 with the same adapter as the one for the zinc-air batteries). They have a constant voltage of 1.55V during the whole lifetime.

Old light meters did not have compensation circuit for varying input (battery) voltage as in that era mercury cells were a simple and reliable current source wth constant voltage. Newer light meters do have so and can thus measure precisely with a cell voltage varying from 1.6 to 1.3V.

Best regards and good luck.

[Michael Geschlecht]

Hello Everybody,

I have found that the SR44 batteries (Silver Oxide.) give a better performance (More smooth & less irregular.) than the LR44 cells do.

Best Regards,

Michael

[jerzy]

Edgar, Michael, yes, I heard before that silver oxide are better than alkaline, neverrtheless as well for silver oxide you need to decrease the voltage, same procedure as for alkaline.

instructions are attached as pdf, sorry, i had to include disclaimer, hopefully nobody feel offended

Leicameter MR conversion to 1,5V.pdf

[AndreasG]

Jerzy, thank you very much for the detailed conversion manual, seems to be not overly complicated, since there is sufficient space for the diode.

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[Toby Madrigal]

I use the Alkaline PX625 batteries in my two Leicameters. The chrome MR on a pair of M3 bodies, also chrome and the black MR4 on a pair of M4-P. I’ve checked the readings compared with a later-purchased Gossen Sixtomat Digital meter that takes the readily available AA battery. The readings from both Leicameters would give underexposure by half a stop. Given that I mostly use Ilford XP2 Super that has a very wide latitude, the difference is negligible. I regularly check the voltage using the battery check facility and when it’s clearly dropped by a good margin, I change the battery. I’ve found that the problems of not fitting correctly, having to use very expensive but very low service life - reporting some 2-3 months (disgusting) with the attendant risks of leakage causing corrosion and destruction of the Wein cell to be a poor substitute for my simple method. 

Diodes? Adapters? Recalibrate? No thanks madam.

[Michael Geschlecht]

6 hours ago, Toby Madrigal said:

I use the Alkaline PX625 batteries in my two Leicameters. The chrome MR on a pair of M3 bodies, also chrome and the black MR4 on a pair of M4-P. I’ve checked the readings compared with a later-purchased Gossen Sixtomat Digital meter that takes the readily available AA battery. The readings from both Leicameters would give underexposure by half a stop. Given that I mostly use Ilford XP2 Super that has a very wide latitude, the difference is negligible. I regularly check the voltage using the battery check facility and when it’s clearly dropped by a good margin, I change the battery. I’ve found that the problems of not fitting correctly, having to use very expensive but very low service life - reporting some 2-3 months (disgusting) with the attendant risks of leakage causing corrosion and destruction of the Wein cell to be a poor substitute for my simple method. 

Diodes? Adapters? Recalibrate? No thanks madam.

Hello Toby,

Welcome to the Forum.

If your meters are consistently underexposing by 1/2 of a stop: Why no simply DECREASE the ISO 1/2 stop or subtract 1.5 from the DIN number. And you might write something like "DIN -1.5" on a piece of paper taped to the back of the meter.

So ISO 100/21 film would be set as ASA 75 or DIN 19.5 (Easier).

I wrote "Easier" above because with MR/MR4 meters, along with some others, it is easier to make more precise setting with the 1 DIN scale than it is to do the same with the 2 ASA scales.

Best Regards,

Michael

Edited October 9, 2021 by Michael Geschlecht