Recently bought a Sigma 10-20. So I took it out for a test run the other day, managed to get about a 100 shots or so. Processed a few back home and I noticed that one had a few weird lines running across the corner of the photo.

Apart from that I think its performing well, sharpness and focus seem to be good. There is some CA and very slight vignetting but from what I hear that is fairly normal.

But back to my point...anyone have experience with something like this? is it something to worry about? I mean it only occurred in a single shot so it could just be a one off.

Thanks