Copyright by Linda Jones. It is against the law to copy photos.
I bought this lens because I really can't carry the 500mmf4, and I like to shoot while walking. Struggling with teleconverters on my 40D 300f4, I thought I'd try the Sigma. Wasn't happy with its long focus beyond 400mm. I decided to try it on the 20D and it is an amazing lens for the price and weight. My 40D is going back for some back focus problems that I have dealt with all year.

Faster focus than my canon IS lenses with teleconverters, which was what I worried about. The autofocus on the sigma works extremely well. Colors and sharpness are excellent on the 20D. I realize now the 40D has some focus problems, and it wasn't my 300f4, nor the sigma. I will add a few more full size photos here, below the finished photos. Very little processing needed. No color changes. Most are just quick shots, slightly sharpened in the signature photos. More non processed full frames in the lower half of the album.[#15-21] All hand held. I will now address the softness at a distance.

After two weeks use, I have concluded the 500mm distance works well on targets within 50ft. Beyond that distance I get many soft focuses. I will ask Sigma to re-calibrate for distant targets between 400mm and 500mm, because I really love the colors, which rarely requires ANY processing for contrast/saturation. If Sigma can tidy up the longer target focus of BIFs further away I will be very happy with this lens. Closer targets are beautiful, a bargain for street and backyard shooting. And they do sharpen well in PP. Realize though most of these are resized which renders a sharper photo. It also may just be an issue with Canon autofocus system, because when it focuses right on target it's not bad at all. I will call them misfocuses for now. It may not be a total lens problem. I am curious as to how the Nikon users feel about this lens, and whether the Nikon focus system works better with it. My review seems to coincide with other canon users.