Oly 35 SP meter drifting

[Max Pegler]

Evening all,

I see on the news NY is buried under snow, here in Sydney it's hot. Fire Bans this weekend.

Back to the point: Point at anything, the meter drifts down. Using SP has an instant adjustment, but then then needle moves....

Why is this? I can only assume less than fresh batteries. It has been recalibrated to 1.5v. if that's relevant.

TIA,
Regards
Max P

 

[David Hughes]

Hi,

Welcome aboard.

My money's on a new battery being needed. The non-mercury ones fade slowly but will surge for a while when first used, even when on their last legs. I don't know if it's a balanced circuit so can't comment further.

Regards, David

 

[Solinar]

Question: Are you using an alkaline cell?

A used alkaline cell with 60% of its battery life left will behave like David describes, with an initial surge and then settling down to a lower output.

I use silver oxide cells with a Schottky diode as a regulator in both my 35RC and 35RD.

http://www.rokkorfiles.com/conversion.htm

Best Regards,

 

[john neal]

^ What Andrew said - alkaline cells are a real nuisance.

 

[02Pilot]

I've had good luck with 675 hearing aid batteries in my SP (and other cameras). They don't last forever (6 months to a year, depending on usage and storage conditions), but they drop off fast when they go.

 

[Max Pegler]

Thanks all

So which is the correct reading? The initial, or the settled?

TIA
Max P

 

[Solinar]

Max - with an alkaline cell - it may be neither.

Check a variety of outdoor and indoor scenes using both the 35SP and another camera or hand-held light meter that are known to be accurate. Then compare your findings.

Best Regards from:

 

[julio1fer]

Your description fits with a drained battery, especially if it is a zinc-air type.

About alkalines, not to start a discussion, but I use regularly alkaline 625 batteries in my 35SP, with very good results.

It is perfectly true that the discharge curve of alkalines is more steep than that of silver or mercury batteries. But you also must consider how far do you actually get into the discharge curve. The 35SP has a very low current drain (about 50 microamp). Unless you start with a non-fresh battery, or shoot a lot, you should do fine changing the alkaline once a year.

In other words, for this application you are looking at shelf life of the batteries, not discharge curves.

FWIW, my current alkaline has been three years in the camera and works fine. I shoot B&W, including films such as Pan F+ or TMX where you want to expose accurately.

With a fresh alkaline, you should correct ISO (i.e. dial a lower value), about 2 stops as compared to a mercury type. The alkaline gives more voltage than mercury types, so the meter thinks it sees more light and gets optimistic. You may compare with a light meter in a reproducible situation, and do your ISO correction for alkalines exactly.

A technician can easily adjust the camera for alkalines, too.