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06-26-2010, 08:32 PM   #1
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SpecialK's Avatar

Join Date: Dec 2006
Location: So California
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Overexposure problem...

Recently got a Sigma 150-500 (f5-6.3). Used it lightly twice at the park, and all seemed fine.

Went to the zoo and elsewhere today, and had significant but intermittent exposure problems.

Here are just a couple examples. They are extracted jpgs from the PEFs. Nothing additional, and they include the duds. Oh, and I did not rotate them either. This is only an exposure evaluation, so go easy :-)

Consecutive shots... (And I look a lot like this guy right now, but he has more hair.)


Bracketing is off. No EV compensation. P mode unless I accidentally move the dials into Av or Tv. ISO 400. (The exposure values actually used probably would be ISO 100 :-(

I posted 200 shots at the link below so you can see the sequence and that is it a hit or miss thing. I understand dark gorillas and white birds affect the meter - but this is beyond those effects.

Problem pictures by KylePix - Photobucket

My theory is that it's a contact thing between the lens and mount.

Note that some of the new Bigmas and these related cousins appear to have a service recall for autofocus issues and this lens falls within the serial number range - but the autofocus seems to operate normally - this is different.

This one will get exchanged or serviced, but any ideas?

(Wheatfield - I know your view on Stigmas :-)

Last edited by SpecialK; 06-26-2010 at 08:43 PM.
06-27-2010, 11:18 AM   #2
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
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Posts: 10,686
I'm assuming you meant to post this in the DSLR or lens forum, and not PP, then? Since as noted, the exposure selected by the camera seems off - it's not a question of the slow aperture blades or something else causing the lens not to stop down correctly - it seems mostly likely to be some sort of camera issue (assuming it doens't turn out to be something silly you're forgetting, but you seme to have covered the bases in making sure bracketing is off, you're in multi-segment metering mode, have compensation off, etc - and overly *bright* exposures seldom results from an exposed viewfinder).

Anyhow, I've moved this to DSLR...

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