Is is possible/practical to adjust the Gost scale light meter on a Kiev 4M to work in ASA values?

Question

I just received a Kiev 4M (Ukraine-built Contax II or Contax III variant made with repatriated equipment from the Zeiss factory). This is the version with a selenium (or silicon?) light meter on the top of the camera, just under the accessory shoe. It's a "center needle" type, where exposure is set on a dial around the rewind knob, with film speed scale in the old Soviet Gost system (Gost value is 90% of ASA, so Gost 100 film would be ASA 90), and you meter by turning the exposure dial until the meter needle is on the diamond mark, then read the exposure (shutter and aperture values) off the scale and input them on the lens and shutter speed dial.

It's a fairly simple meter to use, and more convenient than carrying a separate meter, though its limited sensitivity makes it less useful indoors (a very common issue with selenium meters).

What I'm interested in is whether it's reasonably easy to adjust this meter to read 10% lower, so I can set ISO/ASA linear scale film speed on the metering scale directly.

There's a tiny screw inside a protective collar on the back of the camera's top cover, under/behind the meter. Is this screw to adjust the meter, or the rangefinder? If the former, is a 10% change in reading practical to apply with this screw?

Answer 1

Relevant information is available both at the Kiev Survival Site and in Isaak S. Maizenberg's book All You Need to Know About Design and Repair of Russian Cameras (1996). The screw you mention is used to calibrate the galvanometer scale. Of this, Maizenberg writes:

To shift the galvanometer's scale, insert a screwdriver in the screw slot [...] and slightly turn it. If the screw does not turn, you should somewhat loosen the nut that is fixing it, and tighten it after the adjustment is completed. The galvanometer's scale should be shifted by small amounts. (p. 283–284)

(This is actually in connection with discussing the Kiev-3, but as he notes later on in the book, the advice applies equally to the Kiev-4.)

Maizenberg also says that

[i]f the exposure meter readings deviate from the real value by over 50 percent, the meter should be adjusted with the aid of the calculator. (p. 284)

The calculator is the round part on top of the camera, and its disassembly is covered by Kiev Survival Site (see link above). But from Maizenberg's writing I take it that <50% adjustments can be carried out using the galvanometer scale fine-tuning screw alone.

Having said all that, a 10% difference is likely to be entirely negligible, at least with negative emulsions, and I'm not sure a selenium meter's accuracy is much more than that to begin with (?). Anyway, it should be an interesting exercise to see if the meter can be calibrated against an external standard using the screw alone, as this is a non-invasive procedure. I'm not sure I would go to the trouble of disassembling the camera unless the meter was widely off (by several stops).

Answer 2

The Russian standard GOST is a similar system to the American ASA system. The ASA system is based on 0.10 density above base fog whereas the GOST is based on 0.20 above base fog. A 90% conversion factor works but --- old selenium based meters use a pivot and jewel bearing that is likely dry of lubricant (whale oil was used). A working selenium meter is a better match to the human eye/brain -- its an OK match for panchromatic film.