I recently purchased the Sigma 30mm f/1.4 lens for my Nikon D80. As a bit of background, reports on this lens are mixed. A significant portion of reviews mention a 'front focus' problem with this lens. Everybody else seems to rave about it. I'm really having a hard time with this lens and I'd like some feedback on a few samples that I have posted: http://picasaweb.google.com/greg.pickens/SigmaTest In short, I'm trying to decide whether or not to keep the Sigma. I bought it for its short focal length and wide aperture, but if it won't behave with autofocus then I'll never get much use out of it. I can only keep it for one or two more days before I have to return it. I'm open to better/more testing suggestions. Any photo tagged as 30mm is the Sigma. The photos tagged 60mm are from my Nikkor 60 Micro, which I consider to be a sharp lens. All are autofocus shots in moderate to strong light. The camera is set to AF-A focusing. I shot aperture priority on all shots, with 'single area/normal zone' selected for autofocus. The text crop of the REI ad is from a setup I made this afternoon to try to fairly compare the two lenses. Due to the focal length difference I had to re-do the setup between lenses, so it isn't a perfect comparison. I see a profound difference between the Sigma and the Nikkor at the same aperture (2.8, the lowest the Nikkor goes). The Spongebob photo I took to showcase the soft focus issue I think that I am seeing. On the photo where Spongebob is parallel to the focal plane nothing seems in particularly sharp focus to me. In the example where I shot him at an angle, some portion (more to our right) does seem to be in focus. Those shots were at a very wide aperture, but I'd still expect a flat image to be in better focus than I saw with the flat-on photo. The REI ad doesn't seem to be TOO bad, but when compared to the Nikkor you still see a pretty profound difference in sharpness/contrast (focus?). The cat photos are with the Sigma and Nikkor, both at f/5. Hard to compare of course since the cat is always on the move. The Sigma certainly doesn't look so bad here. The flower doesn't look too bad either, but that's at f8. What I don't show in the gallery are any people shots. I took several of a friend and self-shots of myself. None of them looked sharp to me, but perhaps my expectations are too high for wide-open operation. Finally, check out the distinct lack of sharpness on the presidential seal photo. That's a raised emblem, and I couldn't get it any sharper than that in five tries.