View Full Version : possibility to trick the light meter?
I have a Konica Auto S3, which is a really great camera. But sometimes it's annoying that I can only shoot film up to 800iso, whilst I never use the settings below 100iso.
I read that when using batteries with the wrong voltage the meter isn't working correctly. Is there any possibility to use this to my advantage, e.g. using a higher voltage battery to get meter readings for up to 3200iso? If it's possible, which batteries would do the trick? Or will using higher voltages damage my camera?
At Photoethnography (http://www.photoethnography.com/ClassicCameras/index-frameset.html?KonicaAutoS3.html~mainFrame), Karen Nakamura says "The Konica uses the much maligned PX675 mercury battery that is no longer available in the U.S. An alkaline or silver-oxide 375 battery will also work but the meter will read slightly fast", which suggests that a silver oxide battery might do what you want (I guess you'd have to get one and try it to find out exactly how fast the meter would read). But at least she implies that it won't damage the meter.
Does it have exposure compensation settings? Or you could meter off something a stop or two brighter than your subject and use exposure lock, if it has that.
If you overexpose 1600 film by one stop it won't be a disaster.
i just found out that it already has a 1.5v battery in there instead of the 1.35v.
i'll see if i can get a battery with a higher voltage and check the meter against my other cameras...
I don't think there's much you can do short of opening it up and adjusting the metering system. Perhaps a camera tech can set the meter to read a stop or two high instead of the more typical adjustment for alkaline batteries. it might be worth asking around at any shop that repairs cameras. Obviously this approach would mean the camera's ISO indicator would be half or a quarter of what the meter was reading for, but you'd only lose 25 and 50. Not that big a deal.
What happens with the S3 if there isn't enough light? Does it lock the shutter or just give a warning light? I'm thinking you might be able to get it to shoot wide open if you use the shutter priority to find a speed where there is enough light for 800, and just increase the shutter one or two stops to get 1600 or 3200 wide open. If the camera lets you shoot beyond what it meters.
Possibly one should bear in mind that the photo-cell/diode/light-sensitive-thingy may well not be linear, if you try to read light-levels in which it was never designed to be used ? Having said that, there must have been a means of calibrating the meters during production so you may be able to 'gain' half a stop with that potentiometer etc. Two stops sounds a lot though, as the sub-assembly tolerances would probably not need that much adjustment(?). Is there a service manual anywhere with which you adjust the meter against another, accurate one ? Interesting idea though.
I don't think there's much you can do short of opening it up and adjusting the metering system. Perhaps a camera tech can set the meter to read a stop or two high instead of the more typical adjustment for alkaline batteries
Different camera I know, but I was able to recalibrate the Canon GIII one stop off so it will measure properly with 1600 film.
It was a bit tricky, and involved physically adjusting the meter itself slightly and then electrically recalibrating it.
When I did this, I used a fresh "improper" 625 battery, so two birds (1600 film and the commonly-available battery) were killed with one stone, so to speak.
This was done 18 months ago and it's worked fine ever since.
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