How to adjust for 1.5V alkaline replacement for mercury

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There is a thread further down on the use of zinc/air batteries as replace ment for mercury cells that's been phased out. My question is if I use an alkaline replacement that is 1.5 volt how should I calibrate the meters so it will not be under-exposed. I put one into a Rollei XF35 and all the shots came out under by I think 2 stops. Have not try it in a Leica SL2. I don't have the CRIS adapter but the alkaline replacement can be found where I am quite easily. Any help in this matter is most appreciated.

-- Steven Fong (steven@ima.org.sg), August 10, 2001

Answers

Unfortunately, there is no stable adjustment that will work for the entire life of an alkaline cell. Alkaline cells have a sloped power delivery curve as they reach exhaustion, so as time goes on the meter will read differently no matter what you do.

Invest in a couple of the CRIS adapters and use silver oxide cells. They work *far* better.

Godfrey

-- Godfrey (ramarren@bayarea.net), August 10, 2001.


I was able to simply use a MS76 silver-oxide cell encased in a washer from a dead Wein cell in my Rollei 35s, by resetting the ASA speed. Eventually I removed the retaining ring for the ASA dial and re-set it so now I can use the marked speed. But that didn't work on my SL, the response to the 1.5v wasn't linear, i.e. if I compensated the ASA to get an accurate reading at the bright end, it was off at the low end and vice-versa. Ended up with the CRIS adaptor.

-- Jay (infinitydt@aol.com), August 10, 2001.

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