OM3 Light Meter Values Changing Depending on Lens

4r36

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Hello everybody,

I would like to ask you some advice on how to deal with a problem I'm facing with my Olympus OM3.

Today I was shooting with a Zuiko 50 f2 Macro, and I got suspicious about the values the camera meter gave me. In my opinion, it was underexposing of about 1 stop . I changed the batteries to make sure they were not the cause of the problem (I replaced them a few days ago) but I was given the same values. Then I changed the lens, replacing the 50mm with a 28mm, which was CLAed recently. This time I was given -1 stop, so I wonder whether this means that the problem lies in the lens in fact. What would you do in my place? Would you send the 50mm for a CLA and keep the camera (which apart from this issue works flawless) or would you also have the camera checked? An OM3 without a properly working light meter is a real pity, so I'm undecided on what to do...
 

Sirius Glass

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Have the camera checked with all the lenses. It might be one adjustment or a complete CLA.
 

faberryman

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Were you taking readings from a grey card or other uniformly lit surface?
 

Jimskelton

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The default metering is center weighed. The 28mm will be metering over a wider area which may influence the results.

Maybe try spot metering the same area and see whether they are both the same. If not, I would suspect the 50mm lens.

Also, if you have a stand alone light meter, it would be good to compare the results with that.
 

benjiboy

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What was the effect on film?, and have you considered that different focal length lenses have different acceptance angles.
 

MattKing

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Are you comparing just the in finder meter readings, or are you checking this on film?
How close is your target? The 50mm macro does allow you to get close enough to start experiencing the need to adjust exposure due to change in magnification - the same as the bellows extension adjustment that LF shooters need to deal with.
And if you are fairly close, the wider field of view of the 28mm might be coming into play.
 
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4r36

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Yes, I used the spot metering and not the center weighed to make sure the wider area was not the problem. I don't have a stand alone meter but I tried to use a meter app with my smartphone. Not sure about the reliability of it, though.
benjiboy said:
What was the effect on film?, and have you considered that different focal length lenses have different acceptance angles.
Click to expand...
I didn't develop the film yet. I bracketed a few shots to compare them when I do it. As regard the different acceptance angles, I assumed this might affect the center weighed but not the spot metering...

Thank you guys. I think I'll make some other tests, develop the film, and then decide whether having the camera and/or the lens checked...
 

MattKing

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If there is a problem, it might be with the connection between the lens and the camera, so it would make sense to have both checked.
Do you have access to another 50mm lens? That might help eliminate the acceptance angle factor.
 
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4r36

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MattKing said:
If there is a problem, it might be with the connection between the lens and the camera, so it would make sense to have both checked.
Do you have access to another 50mm lens? That might help eliminate the acceptance angle factor.
Click to expand...
The target was not in the macro range, but thanks a lot for the advice. I have two other Zuiko 50mm, so it's definitely worth comparing them!
 

Bill Burk

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I’ll be damned. You’re right. Other lenses say f/2.8 but the 50 f/2.0 macro says f/4 on my OM-3 spot and average on a gray card.

Maybe it’s 2/3 stop difference but it’s real.
 

ic-racer

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Inside the lens, the aperture ring interfaces in two places that can be out of adjustment.
1) The aperture ring communicates the aperture to the camera mechanically during metering.
2) The aperture closing lever communicates with the aperture ring to set the correct aperture during exposure.

Removing the wrong screw when disassembling a lens can destroy those critical alignments.
 
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4r36

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Bill Burk said:
I’ll be damned. You’re right. Other lenses say f/2.8 but the 50 f/2.0 macro says f/4 on my OM-3 spot and average on a gray card.

Maybe it’s 2/3 stop difference but it’s real.
Click to expand...

Oh, interesting!!!
 
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4r36

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Thanks a lot for the info. Unfortunately I do not have the competence to check myself if something is wrong there. I'll just seize the occasion to have the 50 Macro checked by Gordon of OM-labor. The question for me is whether to send him also the camera. It's not so much a problem of money, but of departing from it for a while xD
 

Ulrich Drolshagen

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4r36 said:
Thanks a lot for the info. Unfortunately I do not have the competence to check myself if something is wrong there.
Click to expand...
You can check with another lens of the same focal length. Dial in say f8 on both and compare the position of the levers which transfer the info to the camera. This must be the approximatly the same
on both lenses.

Ulrich
 
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4r36

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Ulrich Drolshagen said:
You can check with another lens of the same focal length. Dial in say f8 on both and compare the position of the levers which transfer the info to the camera. This must be the approximatly the same
on both lenses.

Ulrich
Click to expand...

Great, thanks for the tip!
 

Sirius Glass

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4r36 said:
This is arguably what should be done to dispel any doubt, indeed...

Uniformly lit surface. Tomorrow I might try with a grey card...
Click to expand...

My grey card is so old, the grey is turning to white!
 

MattKing

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Bill Burk said:
I’ll be damned. You’re right. Other lenses say f/2.8 but the 50 f/2.0 macro says f/4 on my OM-3 spot and average on a gray card.

Maybe it’s 2/3 stop difference but it’s real.
Click to expand...
I'm unsure, but are 4r36 and Bill Burk not actually saying things that are opposite to each other?
Can 4r36 express the situation in the same way as Bill Burk? If the OM3 says the correct exposure with the 50mm macro is f/4, what does it say the correct exposure is with the 28mm - f/2.8 or f/5.6!?
 
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4r36

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Ahaha yes sorry for the confusion. It's the same. The 28mm would say f/2.8 too!
 

MattKing

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Could the 50mm f/2 macro lens be so magical that its T values are a whole stop more efficient than its f/stop values?
Maybe that is why it is so expensive on the used market!
 
OP
OP

4r36

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MattKing said:
Could the 50mm f/2 macro lens be so magical that its T values are a whole stop more efficient than its f/stop values?
Maybe that is why it is so expensive on the used market!
Click to expand...

If this is the case, I expect the Zuiko 100 Auto-T f/2 to say no less than f/11
 

Bill Burk

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MattKing said:
Could the 50mm f/2 macro lens be so magical that its T values are a whole stop more efficient than its f/stop values?
Maybe that is why it is so expensive on the used market!
Click to expand...

Maybe it does have better T values.

I thought I was seeing 2/3 stop.

It wasn’t cheap new (thanks mom).
 

BMbikerider

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Really? The all the Olympus camera i ever owned had the meter reading taken off the shutter blind which was a type of matrix pattern of black and white squares. But the focal length of a lens was well known to give differing meter readings due to the acceptance angle of the light.
Have you tried it with spot metering with the light coming off a grey card and comparing it with that of a good hand held meter
 

Ulrich Drolshagen

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BMbikerider said:
The all the Olympus camera i ever owned had the meter reading taken off the shutter blind which was a type of matrix pattern of black and white squares.
Click to expand...

Obviously you just came in touch with cameras with electronic shutter. The cameras with mechanical shutter, OM1 and OM3, lack this property.

Ulrich
 

MattKing

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BMbikerider said:
The all the Olympus camera i ever owned had the meter reading taken off the shutter blind which was a type of matrix pattern of black and white squares
Click to expand...

Ulrich Drolshagen said:
Obviously you just came in touch with cameras with electronic shutter. The cameras with mechanical shutter, OM1 and OM3, lack this property.

Ulrich
Click to expand...
The OP isn't metering and then exposing film. The OP is speaking of the reading available through the viewfinder. Even the cameras that do offer off the film metering - like the OM-10, OM-2 and OM-4, also have a separate metering system that feeds the viewfinder display. The OM-3 might as well, because I believe, but need to check, that it also has off the film flash metering.
 
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