thanks
----- Original Message -----
From: "dreammoose" <dreammoose@xxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Thursday, April 04, 2002 12:32 AM
Subject: Re: Battery conversion, Was [OM] A sad OM-1n story
> The history is simple. Mercury batteries have the most stable voltage
> through their useful life, so many camera and light meter manufacturers
> used them. Light metering with mercury batteries tend to be very
> accurate and stable until they go and then the meter just quits. Thus no
> bad exposures, but the need to carry a spare. I had the battery in my
> OM-1 go out in Guanajuato, MX almost like a switch being pulled many
> years ago. I sucessfully used the exposure guide from the film box until
> I found a new battery a few hours later.
>
> More recently, environmental concerns led to outlawing mercury battery
> production in the US. I think all production in Europe has stopped now,
> too, but there are still some Varta cells floating around. The problem
> is that mercury cell voltage is 1.35v, while the 625 size cells used
> with other technology are about 1.5v. This leads to a significant
> exposure error (2 stops?). As long as your mercury battery lasts or you
> can find others, you are fine. When you put in the spare, it's time to
> start looking at alternative battery solutions.
>
> Threre are several solutions. When you have your camera CLAed, the meter
> is adjusted anyway and can simply be adjusted for the higher voltage.
> This adjustment can also be done by itself. There is a thingy called an
> MR9 adapter, which is the shell of a 625 battery with a shottsky diode
> and plastic plug in it which holds a 357 silver oxide battery. The
> diode forward voltage drop adjusts the voltage and the whole thing fits
> where the mercury 625 battery went with no adjustment or modification of
> the camera. There are available from John H at www.zuiko.com . Handy
> tinkerers can just insert a shottsky diode in the meter circuit in the
> camera.
>
> >I have heard mentioned a few times about this battery conversion,
> >I was wondering if someone could explain it to me (why it is done etc)
> >
> >When I bought my om1 the man in my local shop put a new battery in
> >it saying the one in there was the wrong type.
> >Also bought a spare from him. Do i need to get mine converted?
> >The new battery is a mercury one i think
> >Thanks
> >
>
>
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