Anyone uses solar cell to measure light?

[Chan Tran]

To have a meter without battery most of the old meters used selenium cell. With the popularity of silicon solar cells today used to generate electricity does anyone try to use them as sensor for ligh meter?

 

[AZD]

Yes, on occasion. I have an old Kalimar B-1 my grandfather gave me almost 30 years ago. It still works with surprising accuracy. As in the “average” reading between Kalimar and an SLR with TTL meter is no less accurate than between the SLR and another.

When I first got it I was told to put my palm in the same light as the subject, meter, and add a stop. Maybe not zone system accurate, but it rarely results in a bad exposure. Its main advantage is its size - tiny.

Low light accuracy isn’t great, but it has a separate booster which does help. I don’t use that much, though.

 

[Chan Tran]

I think your grand father's Kalimar B-1 has selenium cell not the type of silicon solar cells that are widely available today.

 

[bernard_L]

I tried to restore a Weston Master V using a Silicon photocell bought on a Chinese site. Also had a Lee acetate green filter to correct the wavelength response.

I stumbled on the problem of cutting the Si wafer to the size of the original Selenium cell. Whatever the technique used

• scribing, like glass or Si substrates
• cutting with a dremel and a carbide disc

I found that the output of the cell decreased, even after counting the (moderate) decrease in area, especially the open-circuit voltage. Which I ascribed to a shunt conductance appearing along the cut (crystal damage?). Maybe if I had a CO2 laser I could make properly healed cuts?

 

[4season]

Yes, I've directly replaced dead selenium cells with crystalline silicon, and while I have almost zero data on performance characteristics of the original part when it was new, the replacement works pretty well in a compact automatic camera loaded with color print film. The paltry amount of data that I have found suggests that max voltage output for both types is similar, though crystalline silicon produces ~10x as much amperage, so the replacement can be much smaller than the original part.

 

[4season]

Attempting to hand-cut the cells using a carbide-tipped glass cutter produced pretty rough looking results for me. My stash of parts are polycrystalline cells, so the "grain" is random, and the cells don't cleave neatly in any particular direction.

Some flexible amorphous silicon cells are designed to allow easy cutting to size, even with a pair of scissors, but I have not tried these.