Besides my old Leicameter MC, I have a few classic cameras with working, accurate "solar powered" light meters that I'd like to keep that way. I seem to recall hearing that storing them in the dark will likely prolong the life of the cell. I also heard that if there is no exposure to light for a long time, the cell will go dead. Anyone here know the real story about this?

-- Andrew Schank (aschank@flash.net), October 20, 2001

Answers

It is the oxidization of the conductors at the back of the selenium cells that is the problem. All selenium cells will eventually fail. As moisture and heat tend to accelerate oxidization, the old adage to "store it in a cool dry place" would be apt here. Electrical stimulation (exposure to light) may help or hinder the oxidization depending on the composition of the conducting material.

The best people to ask this question of would be:

Quality Light-Metric

Attention: Mr George Milton

Suite 210

6922 Holywood Boulevard

Holywood California 90028

213-467-2265

They repair meters for a living and maintain most of the film industry's meters. From the examples I have seen on Leica-Users, the meters are inexpensive to repair.

Cheers,

-- John Collier (jbcollier@powersurfr.com), October 20, 2001.

John is correct, and the same can apply for any old electronic gear with selenium rectifiers they go bad over time- period. Their resistance increases and throws off the circuit values. On a meter you may be able to adjust for this within the circuit if available and the value is not to far off. Otherwise it's remove and replace, I do it to every old piece of gear I come across aside from the fact that if the darn thing goes up in smoke it's a toxic cocktail for the nose!

-- Dave Doyle (soilsouth@home.com), October 20, 2001.

What may be confusing here is that Selenium meters do tend to "fatigue" with continuous exposure to bright light, but this is a temporary condition rectified by a rest period in the dark. I've come across many "dead" selenium meters including Leica MC's, yet my c.1963 Rolleiflex 2.8F meter still works like a charm.

-- Jay (infinitydt@aol.com), October 21, 2001.

My 1960 Minox B and 1963 Minox B selenium meters are still quite accurate.

-- martin tai (martin.tai@capcanada.com), October 21, 2001.

Besides my perfectly working old Leicameter MC, I've got one on the Rolleiflex that is spot on, and another on an old Contax IIIa that I couldn't believe was still so accurate. There is something cool about a camera with no batteries that even has a working meter. Its hard for me to imagine how some of these cells are nearly 50 years old and still work.

I asked this question because I like to keep my cameras in a glass covered book shelf (instead of some moldy old camera case in the closet!) and I was concerned that the meters would be affected from being in an environment where they received light during the day. Seems like this probably is not the case, so I won't worry about it.

-- Andrew Schank (aschank@flash.net), October 21, 2001.

I have seen many old Zeiss Ikon cameras with dead selenium meter; these were put on the shop window and exposed to direct sun light over long period of time, I think, this burnt out the meter.

-- martin tai (martin.tai@capcanada.com), October 22, 2001.

What is the most reliable and stable type of meter cell material? I understand CDS is not that accurate over the long haul, either. Maybe Silicon Blue is best?

-- Bob Fleischman (RFXMAIL@prodigy.net), October 25, 2001.