9 out of 10 points and recommendedMore versitile than multiple fixed lensesSlightly lower quality than fixed lenses
Sometimes I need more than 300mm. Wanted to wait for a new Nikon telezoom but needed something now. SLR Gear didn't have any test results to help my decision, but I bought one anyway.reviewed May 6th, 2010 (purchased for $999)
The Sigma is better than I thought. From 170-400mm the images are good. Around 200-350 is its sweet spot. Best shots are f8. BUT I have good results wide open in the lower range, and at 500mm f8 the images are acceptable. Biggest issues are: chromic abberations and flare. The CA are correctable in most shots, but the lens seems to lack good coatings on the inner elements so there is some flare and glare. Color richness is better with my Nikkors but in post processing increasing saturation helps the Sigma. At f22 there is a strong starburst when shooting point light sources.
The lens is handy... it goes in my backpack. The image stabilization is very good, after it locks on. It takes a bit longer than most other lenses but allows handheld shots at 500mm. The trick is to get the lens started about a second before you want to take the shot. It's also good when tracking moving subjects. It's a bit noisey but acceptable. Overall, I'm happy the Sigma has found a home in my camera pack. It's not a professional quality lens but if you can use a 1-off lens, then the Sigma is your best bet.