I'm actually posting a review because I'd like some advice. I've seen some comments about sigma's quality control being suspect. I have to believe that I got one of the lemons because the images I'm getting out of this thing at 12mm are virtually unviewable, even stopped down. At 24mm, it's reasonable, but no where near what I expected out of a $600+ lens (and nothing like the sharpness I've seen in online reviews).
So the advice: I've never had to return a lens, but I have to this time. It was purchaced at B&H, but not used for > 2 weeks, so I missed their grace period. So, I assume my next step is to use the Sigma warranty and send it to them for repair/replacment/calibration/whatever. What's the safest, quickest way to get the lens to them and back and ensure they know what to fix and without charge?
If anyone has had success swapping lenses with Sigma, I'd love to hear the best way to go about it. Do I need to include some images? Do I need to photocopy all my documents (sales slip, warranty info, etc.) and include that? How do I include the money for return postage (a check?)?
It's frustrating that I need to pay postage both ways and be without a working lens because they have cruddy quality control. I'm going to work to get this one fixed, but I don't intend to purchase another Sigma lens (at least not without being able to try it out in-store and verify the resultant image quality).