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08-11-2009, 09:05 PM   #1
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50mm Underexposure Problem

This is my first post here, although I've been using the lens review database for some time; It's a great tool.

Anyway, I received an 1:2 50mm SMC-M lens to try off eBay. It looks great, everything seems to functioning as it should, but every single picture taken has been underexposed, maybe 1 or 2 stops. I'm using a P5 and shooting slides, every other shot I've taken with my M 80-200mm has been perfect.

Any ideas?

08-11-2009, 11:24 PM   #2
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Did you manually open and close the aperture to make sure it's not sticking? Usually when older (ebay) lenses underexpose, it's because of oil buildup on the aperture causing it to slow down or stick. Visually inspect the aperture when it's fully closed too.
08-12-2009, 09:53 AM   #3
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I agree with Frank. That should be the only reason it wont expose right. I got a manual 1.7 50mm off ebay a while ago and it meters perfectly on my k20. I usually overexpose my auto lenses a bit to get the look im after but the manual lenses expose just about right for me. Good luck with your problem, hope its something simple.
08-12-2009, 10:21 AM   #4
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Original Poster
The aperture is quick and snappy; no sign of oil. I compared firing it off on a body at slow speeds to my other lens and it seemed fine. Maybe I could try compensating by choosing a wider aperture over the metered one, or just replace it. Shame though, its in great condition.

09-15-2009, 06:32 PM   #5
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I think I have figured out the problem;

I use both a P5 and a P3. Upon comparing the two with the same lens, the P5 metering system differs in values than that of the P3 (it usually calls for a faster shutter speed). However, I use the P5 all the time with an SMC-M 80-200 zoom. Never as any slide been incorrectly exposed until I used the 50mm on it. I use the same lens on the P3 as well and never has there been any problems.

Could anyone account for this discrepancy, and why this is only effecting images taken with the 50mm?
I'd really appreciate it.

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