valdas
Veteran
I have been always puzzled about some strange metering/exposure issue in my OM4T. In some conditions when the meter in the viewfinder indicates 1/30 or 1/60 I clearly hear that the actual shutter speed is much slower - 1/8 or even 1/4. I thought it was something wrong with the meter or the shutter. However, compared to handheld Gossen those exposure readings were correct. Hmmm. Today I suddenly realized that the actual exposure that camera is using is not what center weighted exposure metering shows in the viewfinder but what spot metering reads. Checked the reading from the spot meter - bingo. So, my OM4T does not shoot using center weighted mode, only spot (except in manual mode). It must be that the previous owner "fixed" this camera or is there anything I am missing in settings?
Chriscrawfordphoto
Real Men Shoot Film.
Spot meter should only work after you push the spot button, then the reading will clear and go back to center weighted after you make an exposure unless you used the exposure-lock function.
Keep in mind also that in centerweighted, the OM-4T meter reads light reflecting off the film. If there's no film in the camera, it'll see the black pressure plate and give more exposure than the finder indicated.
Keep in mind also that in centerweighted, the OM-4T meter reads light reflecting off the film. If there's no film in the camera, it'll see the black pressure plate and give more exposure than the finder indicated.
valdas
Veteran
Yes, I know all this. Still - meter shows 1/60 (without pushing spot button), I hear exposure 1/8. I measure the same scene in spot - 1/8. So, basically it shoots the exposure measured with spot without pushing spot button. That's the issue.
p.giannakis
Pan Giannakis
Can you check the screws to see if the top plate has been taken off? Maybe the previous owner "fixed" it and the spot button is constantly pressed.
valdas
Veteran
No, that's not the case - the spot function is only activated after pressing the button - only then the spot sign appears in the viewfinder (and it clears with the clear button as described in the manual). It must be something messed up inside.
dtcls100
Well-known
Unfortunately, this could be a sign of developing circuit problems, which begin with erratic functions. Hopefully, it could also just be a sign of dirty contacts. Try gently tightening the baseplate screws and clean the battery contacts.
p.giannakis
Pan Giannakis
Just to check if I got it right. The meter reading on the viewfinder shows one speed but it shoots with another (that agrees with spot metering)? Can you tape a piece of silver foil and see if the camera shoots on a much higher speed than the one indicated. My OM 2 and 4 can appear erratic when testing them but I have never missed a picture due to wrong reading.
Last edited:
valdas
Veteran
Correct, in default metering mode it shows what appears to be center weighted metering, but shoots the speed what agreed with spot metering. I hear it clearly. In the conditions where spot is the same as average, then it does not matter, but when dark object is in the center then spot is much slower - 2 stops or so. All speeds from 1/250 and slower I can differentiate very well - I was a telegraphist in the army and did Morse code as a sport
p.giannakis
Pan Giannakis
For speeds below 1/45 the OM 4 reads of the film. If you put some silver foil and for an indicated speed of about 1/15 it should close the shutter faster (because the foil is very reflective). That will indicate that it works well. Still I think the best way to check it is to shoot a test film
retinax
Well-known
So if there is no film loaded, wouldn't it expose longer because the pressure plate is probably less reflective than film?
Then if your test, Valdas, was without film, this could be normal behavior.
valdas
Veteran
It is not new to me camera, I shot many rolls with it and this behavior is present with the film loaded.