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Message |
    
Pinotgraves
Tinkerer
Username: Pinotgraves
Post Number: 6
Registered: 10-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 31, 2011 - 03:21 pm: | 
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In the post-mercury battery world, there is lots of discussion about the importance of using the same voltage (or not) in replacement batteries to ensure correct readings from camera light meters.
So, ignorant question--does a higher voltage make for a lower reading from a CdS meter? |
Lrsnrl
Tinkerer
Username: Lrsnrl
Post Number: 16
Registered: 02-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 31, 2011 - 10:09 pm: |
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Try this site;
http://olympus.dementia.org/Hardware/PDFs/
OM1DiodeVer2_1C.pdf
It has the results of a test with different volt-
ages applied to the metering circuit. |
Old_school
Tinkerer
Username: Old_school
Post Number: 54
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 01, 2011 - 07:34 am: |
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Also:
http://www.ihagee.org/batt-adapt-us.pdf |
Prasanna
Tinkerer
Username: Prasanna
Post Number: 67
Registered: 10-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 01, 2011 - 10:00 pm: |
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If your Meter has a bridge circuit then it can take variations in voltage without any appreciable change in the reading. Examples are Prakticas, Pentax SPs and some Olympus OM models. I use button Cell 357 [1.5v] on my Praktica Super TL and the MTLs. On the PLCs I use ordinary torch light cells AA of 1.5 volts though the camera specifies 4.5 V Mallory. They work okay. |
Monopix
Tinkerer
Username: Monopix
Post Number: 213
Registered: 11-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 02, 2011 - 06:20 am: |
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>So, ignorant question--does a higher voltage make for a lower reading from a CdS meter?
Depends...
Some cameras are tolerant others not. Some may go up, some may go down.
If'you're asking about a specific camera then tell us which one and, maybe, someone here will know. |
M_currie
Tinkerer
Username: M_currie
Post Number: 262
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 02, 2011 - 09:44 pm: |
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In most of the cameras I've dealt with (those without voltage tolerant bridge circuitry), the higher voltage gives a higher reading: that is, a higher voltage will produce underexposure.
This is true of Nikon Photomics and Konica Autoreflexes, as well as most of the little fixed lens rangefinders such as the Olympus 35RC.
How much it's off seems to vary. Some come close enough with an alkaline, others require considerable compensating. My Olympus 35RC and Sears 35 RF (a Ricoh in drag) come close enough for print film with an alkaline, under a stop error, and easily compensated with an ASA dial tweak if you're fussy, whereas a Konica T3 will go off by 3 stops or so with silver oxides, not much better with alkalines, and even with zinc-air hearing aid batteries it requires a 2/3 stop offset. |
David_ritchie
Tinkerer
Username: David_ritchie
Post Number: 82
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 03, 2011 - 08:43 am: |
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My experience may not be the same for all cameras, but I found that on my Nikkormat FT-2 that lower voltage resulted in over exposure.My slides taken using an almost exhausted battery were all overexposed.Hope this helps. |
