[Leica] Voltage Regulators

["C.M. Fortunko" <fortunko@boulder.nist.gov>]

LUGs,

Marc writes that most German gear has voltage regulators permitting the use
of other-than-mercuric batteries. About a year ago, I spent quite a bit of
time performing tests on mercury and alkaline 625-sized batteries using my
Gossen, M5, and SL2 as test vehicles and the M6 as a standard. The results
showed that the readings were roughly within 1/2 stop. (Incidentally, I am
convinced that one may be able to observe 1/2 stop variations between
mercury batteries.)

I don't know how valid these results would be as the batteries age. In my
tests, I used new batteries.

I tried to contact Leica in NJ, specifically Mr. Hartmann, but was told that
he is not available. My M5 was adjusted at K&S in Palo Alto by Mr. Hartmann
using a Leica-approved light box. However, I am convinced that it is now 1/2
stop too sensitive. Before, my M6 and M5 would read the same off most subjects.

If there is a regulator in my cameras, then it is probably some kind of a
non-linear device that somewhat compensates for changes in battery output. A
true regulator would require a transistor and some kind of a feedback
network. I cannot conceive of something like that operating at the low
voltages available.

I know that there is an adapter on the market that claims to adapt silver
batteries to the M5 and SL/SL2. I would like to know how to get one. 

BTW, IMHO the meter on the M6 is wonderful.

Best of Light,

Chris