MR THOMAS N CURLEE wrote:
> I got both my bodies back from John H. this week. One is a OM-2 MD
> and the other is a OM-2S. Both needed batteries so I dug around in
> the camera bag and came up with a set of 357's and a set of 357A's (I
> bought them by mistake). I well know that some OM cameras simply
> won't work properly with anything but the 357 but my OM-2S works (at
> least fires) with almost anything I put into it. As long as the
> camera fired properly I figured I could get away with 'wrong'
> batteries for a while.
>
> I checked the metering on both cameras by putting the same 50mm lens
> on both bodies and metering the same blank wall. I got 2/3 to 1 stop
> difference between the 2 bodies. I wasn't too happy about this and
> thought bad thoughts about John H. (sorry John!), figuring that I
> would need to send the camera back for re-calibration. THEN I
> remembered that I had 2 different types of batteries in the cameras.
> I picked up a batch of 357's the next day. Now the 2 bodies are
> within 1/3 of a stop or less. I checked the 2 357A's and found that,
> for some reason, the voltage was different between the 2 cells - 1.
> 498V vs. 1.518V. For what it's worth, a new 357 measures 1.619V.
> The difference (6 - 7 percent) makes a noticeable difference in the
> meter calibration.
>
> Moral: Use the right batteries - the 357.
>
> I found it interesting that the 357A is a alkaline battery. I saw
> 357A and assumed it was the same as a 357. The package was marked
> 357A while the battery itself is marked as a LR44.
>
> For those in North America, the home repair store chain Home Depot
> stocks the 357 for $1.38 ea. This is much cheaper than Radio Shack,
> who had the LR44 marked as the 357A.
>
> I guess I've learned my lesson on what battery to use. Do what John
> tells us to do and use the 357! Now I need to get out and put some
> film through the cameras.
>
> Tom
>
tom,
these little batteries can literally make and break your life when it
comes to taking photographs. one must remember that these little
monsters not only power your meter,which determines your exposure, but
they also power your shutter which make the exposure. there are enough
variable as it is that can throw off your exposure reading, eg a
backlighted scene with a dark subject, that having the improper
batteries will simply throw you off too much. especially if you are using
transparancies for film. these are very unforgiving in terms of exposure
latitude. this is the reason that professional MF cameras are calibrated
to take exposures within 1/3 of a stop!! so lets say your batteries have
more power output than your meter needs, this will make your meter
reading higher, essentially underexposing your pictures, then add to that
the effect on your shutter and you have a really underexposed picture and
we are talking about at least 1-2 stops and for transparencies that's a
no-no.
the other thing to consider is the behavior of these different batteries.
i know that the lithiums tend to have a steady downward ramp then die
while the silver oxides tend to have a steady plateau then die. in terms
of consistency, the latter is more desirable since your exposures will be
more consistent. i don't know how alkalines behave. this is the reason
that i have stuck to silver oxides for my cameras. it is the consistency
that matters the most, just make sure that you have spares for that
inevitable failure!! hope this helps.
francis
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