olympus om10 with a pessimistic meter

[Assaf]

Hi there,
I got this cute camera + 50/1.8 lens for a bargain price.
It's user condition, the light seals should be replaced, which I know how to do easily.
The light meter consistently measures two stops less than there really are. Since it's consistent , for both low light and daylight, I can compenste it with the ISO setting.

However, if I could fix it myself, I's be happy to do so.
So, any clues? Anyone with experience with it?
I confess that I don't really know how the light measurement works - the meter is behind the flipping mirror - facing the first curtain which has white dots on it.
So, how is light measured when the mirror is down and blocking the shutter curtain?
Any help would be appreciated.

 

[Muggins]

IIRC there's an external lightmeter, under the button for the rewind clutch on the opposite side to the manual adapter. Put your thumb over it and see what the LEDs do.

What sort of batteries do you have in it? While both LR44s and SR44s fit, and work, the silver ones (SR44) have a much flatter discharge curve, so it may be that if you have lithiums in they are getting a bit tired. Having said that, I'm not sure which I have in either of mine and have never noticed a difference. They just don't seem to drain batteries at all...

Hope that helps,

Adrian

 

[Assaf]

thanks Muggins,
the batteries are OK, I also changed them to new ones and the measure remained the same.
According to the light metering - do you mean that there are actually two meters? one on the shutter during the exposure and one external prior to the exposure?
I'll try to check it when I'm home
thanks for your help
Assaf

 

[kully]

I've had a couple of OM10's - the metering is deffo through the lens - no external light meter.

 

[Assaf]

OK guys, I did two experiments and got some interesting conclusions.

WARNING - DON'T TRY THIS AT HOME 🙂

I conjectured that there are actually two light meters,

first meter - facing the shutter which takes the metering just before the curtain opens the

second meter - which takes the metering before the exposure is in the prism.

Experiment #1 - I removed the lens and blocked the focusing screen with black electrician tape (not the sticky side, don't worrk). The LED showed no light (1 second), however, the actual exposure where faster and corresponded to the amount of light the camera faced.

Experiment #2 - I removed the tape from the screen, openned the shutter in BULB with a cable release and blocked the internal light meter. The LED showed lots of light but all the exposures were 1 second long.

QED

Well, now I think that the camera is fully functional and that nobody listens to the pessimistic meter (inside the prism).

PS. it's better than solving puzzles, I think that the fun I had was worth the money I spent on this beaten camera ....
Good night
Assaf