>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
>
Ah, batteries, batteries.
Perhaps this is for John Hermansen. I understand why meters were powered
directly by a battery when it was a mercury oxide cell with its long life
and almost constant voltage output up to failure, but haven't subsequent
designs for other batteries had some sort of voltage regulating circuit put
into the chip for the meter? It may be that a battery other than a 357 may
cause some gross failure of a current intensive function like a complete
shutter cycle, but it is inconceivable that the manufacturer of a quality
camera would allow meter readings all over the place depending on the
freshness of the batteries when they are known to be an inconstant voltage
source.
As to the labelling of batteries, I have always used SR44 for my 4Ti
without problems. When I recently bought replacements I decided to try the
357S. I bought them at reputable camera store. They had a large 357 on the
package and in parentheses(SR44W). I assume I got the correct battery.
Winsor Crosby
Long Beach, California
mailto:wincros@xxxxxxxxxxx
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