Summary: LOVE THIS LENS!! My first non-prime lens was a Tamron wide angle zoom and the autofocus was just plain unusable. When I invested in this lens to get more compression in the backgrounds of my portraits, I was shocked at how awesome the autofocus is! Definintely the highlight.
Summary: this is definitely a macro lens. I tried to pull it off as a sports lens, but using rapid fire shutter on this wasn't the greatest. sigma makes great lenses - used it for some portraiture too, that worked a lot better than using it for sports.
Summary: The autofocus is plenty fast and the lens is sharp. The controls are smooth and it just feels good in my hand. The Optical Stabilazation is very good. I have used this lens repeatedly carrying it only in hand, and my images came out very sharp.
Summary: Just bought this lens after using a Canon Non IS version of this lens. The only thing that is different in a negative way is the autofocus. The Canon lens does focus faster, but, not a very noticeable amount. This lens focuses fast enough for me, but I trust the Canon more.
Summary: Not sure if I just got a bundle of bad glass, but I couldn't get this lens to focus on my D7000. Tried it for 2.5 weeks, making many adjustments to fine-tune focus settings, still no joy. 70mm was back focused, 200mm was front focused. For $1000+ I expected better quality.
Summary: Simply amazing lens!! Super sharp and precise, gorgeous bokeh, maybe it is me but feels that my photography is more live when i use it...! I'd buy it again if lost, it comes with me everywhere i go along with my 17 - 50 f/2.8 also by Sigma. Quit fooling around buy it!! :)
Summary: I am not a pro, but do take a lot of photos; especially sports. I am team photographer for my kids soccer teams. I needed something faster for shooting under the lights; this does that. No need for a flash at all. There are circumstances that if in auto mode, the pic is over exposed.