Olympus OM1 MD metering question?

johnha · Oct 19, 2014

Hi all, some time ago I acquired an OM1 MD which was supposed to be fully working, but appeared to show massive under-exposure (needle right at the bottom). The needle however appeared to move in steps when changing aperture and/or shutter speed (I therefore assumed the battery still had some power in it). I've now removed the battery (to prevent it leaking) but now see the same behaviour whether the switch is ON or OFF. Is this usual behaviour - I din't expect the needle to move without a battery?

John Koehrer · Oct 19, 2014

The meter only responds to light with a battery.
The linkage to the needle is mechanical and may be fouled. Part of that internal link from the
aperture ring to the meter itself is a thread that may have jumped it's pulley.

Xmas · Oct 19, 2014

The meter will behave as you describe when the ISO, aperture and shutter speed are outside the normal range.

try f5.6 /125 400 ISO

note it is difficult to meter with the camera in low light, unless you keep this in mind, this is described in the user manual which you can down load for free.

ic-racer · Oct 19, 2014

A string moves the whole meter assembly. If the meter is electrically dead, it still can be moved around. How are you meter readings with the new battery?

Xmas · Oct 20, 2014

ic-racer said:
A string moves the whole meter assembly. If the meter is electrically dead, it still can be moved around. How are you meter readings with the new battery?

They will be the same unless he tries settings in the allowable range the OMs have too much packed in for their size and technology.

Rotating a meter just too cunning.

baachitraka · Oct 20, 2014

I may forget about the built in meter in OM-1n and use an external one.

Xmas · Oct 20, 2014

baachitraka said:
I may forget about the built in meter in OM-1n and use an external one.

They work ok even in low light and are easy to adopt to

either zinc hearing aid batteries with plumbers rubber ring easy

or

silver oxide with one $ Schokety diode from crystal set kit if you can solder and undo four screws

note there is a wayward spring after removing screws before removing base put the camera in a zip lock then remove plate.

The OP problem only appears in available darkness and can be detected by looking at needle through a on off or off on sequences. The other OMs have built in obselence of electromagnets and LCDs.

baachitraka · Oct 20, 2014

Micheal Spencer did CLA and converted the metering circuit to take Silver Oxide cell. It works but these days I rely on incident meter reading.

baachitraka · Oct 20, 2014

I personally would have preferred OM-1(n) without a meter so I can have a clear(unobstructive) viewfinder.

Xmas · Oct 20, 2014

baachitraka said:
I personally would have preferred OM-1(n) without a meter so I can have a clear(unobstructive) viewfinder.

Well I'm a dinosaur as well as I normally carry a Weston and invercone for incident but also take zone one shadow readings.
But providing I turn the meter of the OM1 off I don't find the needle a distraction, if I left it on it would be too compelling and Id miss shots adjusting the aperture.
Frequently I lock the mirror up and use instinctive point.

johnha · Oct 20, 2014

Thanks for the replies. I have a Pentax S1a (with no metering at all) and find the completely uncluttered finder much less distracting when composing the frame.

Having thought about it, I'll just use my hand-held meter and see whether the rest of the camera works before worrying about another battery.

OndrejP_SK · Nov 10, 2014

As has been said, the meter galvanometer is linked by cords to aperture and shutter speed rings as well as to the ASA setting knob. If you set ASA 1600, B and lens 2 or 3 stops from wide open, the needle should center between the + and - marks.
Most probable cause why meter doesn't work is a corroded wire from the battery terminal to the meter at the top. Usually the wire can not be extended, only completely replaced which requires removal of the front plate and mirror box. After replacing the wire and adding a Schottky diode in series it usually works fine again with 1.55V SR44 batteries.

Olympus OM1 MD metering question?

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