It focuses fast and accurately; IQ is superb, almost good as Nikons' 70-200mm; It is almost as heavy too. Build quality is excellent and image stabilization works well, about 3 stops.

Durable; Fast / accurate auto-focus; Nice Bokeh; Rugged; Strong Construction

Heavy

I have been waiting for this lens for a year. Finally I bought it one week ago. Let me tell you it is a Sharp lens! Tamron and Sigma are catching up with Nikon and Canon. This is actually a pro lens to DX shooters with optical stabilization.

According to dxO labs this is the best lens for Nikon d7100! So I bought it and after a few hundreds shots I defenetly can confirm that! It's amazing! Great quality and outstanding photos!

Great zoom lens with large aperture! Being able to get telephoto with f/2.8 is what I needed and the lens produces great pictures on my Nikon D7000. Build is very solid, zoom and focus rings are smooth. Only issue is its a bit heavy, but what do you expect from lens with this capability.

Consistent Output; Durable; Fast / accurate auto-focus; Nice Bokeh; Strong Construction

Heavy

Great lens, I haven't came across any problems with this lens, it has a great focal length especially with a crop factor of about 1.5x. The only cons I can think of is it dosnt have the quickest focusing when it comes to sports, also i would of liked to see the manual mode button on the side, lastly...

I really like this lens. It is my first "professional" grade lens and I am VERY impressed. The sharpness of my photos is a magnitude above that of the kit lens for my Canon T3i. Photos taken with this lens are tack sharp! I read some reviews stating that at F2.8 there is softness at the edges.

Much Cheaper Than L Glass; Quick Focus; Very sharp

Heavy; Large; Not For Full Frame Camera

Sigma's new APO 50-150mm f/2.8 EX DC OS  HSM lens is one of only two large-aperture tele-zoom lenses for cameras with APS-C sized sensors. (The other is the Tokina AT-X 535 Pro DX AF 50-135mm f/2.8.

You need a fast; effectively-stabilised lens for portraiture or product photography; You want a zoom lens that can be used with polarisers and graduated filters; You require good flare resistance in backlit situations.

You have a camera with a 'full frame' (36 x 24mm) image sensor, You need a small, lightweight lens; Don't buy this lens if, You have a camera with a 'full frame' (36 x 24mm) image sensor, You need a small, lightweight lens

The new Sigma APO 50–150mm F2.8 EX DC OS HSM designed especially for APS-C size image sensors is a fast f/2.8 telephoto zoom lens with a focal length equivalent to 75–225mm in 35mm format. Un-boxing it you have the well-padded sturdy case that comes with every Sigma lens in this range.

Fixed f/2.8 aperture; Four stops OS; Pro focal range; Lightweight for a telephoto

Too large for most hobbyists; Only for crop sensor; Vignetting

I used to be an owner of a Sigma 50-150mm f2.8, before i got Tokina 50-135mm f2.8. Sigma had problems with front focusing, so i sent it back to service. They somehow managed to adjust the focusing, but after using it for a year I sold it, because the image quality of Sigma 50-150mm f2.8 was not...

HSM motor; EX built quality

focusing issues; image quality is just average

At first glance, the new Sigma 50-150mm f/2.8 EX DC ($680, street) appears to possess an unusual focal length range. But when you do the math, multiplying by a 35mm lens-conversion factor of 1.4X, it becomes a more familiar-sounding 70-210mm equivalent.