Just got back from my first outing with my newest addition to the collection. The Sigma 8-16mm f/4.5-5.6! So far I like it a lot, but using this wide of lens will definately take some practice to make compelling shots. the only real negative thing I have to say is that it doesn't seem to play well with AF on my 50D unless focusing very close. After noticing a couple shots with missed focus I ended up focusing manually for the rest of the outing. Heres some samples: 1. 8mm. Was a little soft, this was when I noticed the AF issue. 2. 11mm 3. 8mm 4. 9mm 5. 8mm 6. 8mm 7. 8mm 8. 100% crop of above photo... I think this is the sharpest lens I own (for now All shot in .jpg format, all at f/8. No additional sharpening or distortion correction. I did play with exposure in lightroom though (recovery, fill, exposure and blacks). Larger versions and a few more shots can be seen in my flickr. Thanks for checking it out!