Excerpt: Bought this lens to use for both video and photo and I can't find one good thing about it. I returned it almost immediately it was that bad. It had major front focus issues and even with using my cameras AF Micro Adjustments I found the focus to be softer than I even thought was possible.
Cons: Blurry Focus, Heavy, Poor in Low Light, Slow Focus
Summary: I tried two copies of this lens and was very disappointed, it was not sharp on the edges or corners when shot wide open at any focal length. I would not recommend this lens for professional use.
Summary: Buy this if you want BLURRY, OUT-OF-FOCUS, and NOT SHARP pictures! Maybe I got a dud but I HATED this lens. I probably got 20% of my pictures in focus. Used with a Nikon D5100 and tried all variations of settings, lightings, environments.
Excerpt: I have the Sigma 70-200 f/2.8 and have had no issues with it for the 7 years I've used it, so I had no hesitation in picking up this Sigma 24-70 f/2.8 - but after receiving it, I only got 57 photos out of the lens before the lens stopped focusing (it would not focus in either the auto or manual...
Excerpt: Big disappointment! I tested this lens both indoors as well as outdoors and could not get a sharp image at any range or aperture. My first time buying a non-L lens and will be my last. Maybe I got a really bad copy but I am not taking a chance in getting another one.
Excerpt: See "Front Focus" by Rick on 3/2/10. I had the same problems, but sigma told me to use a ruler at 45 degrees and send them the lens and pictures. I did and still have the same problem. I don't have time to try to to do exchanges. I am hoping I can send it back and buy the more expensive Nikon.
Pros: Durable, Easily Interchangeable, Rugged, Strong Construction
Excerpt: I wish I could give this lens no stars. Let me take you through the initial two months of ownership of this "so-called Professional" lens. I purchased the lens on September 29th and clicked it on my d700, aimed at my daughter and pressed the af-on button....nothing.