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

Very nice lens for indoor portraits or outside. Focusing is silent fast and accurate. Very well made with focus friction override and zoom anti-creep (when you hold the camera up or down). You'll probably have to hold the lens when shooting as it is somewhat heavy.

Technical Specifications Lens Construction: 18 Elements in 14 Groups Angle of View: 27.9 ° - 9.5 ° Number of Diaphragm Blades: 9 Blades Minimum Aperture: F22 Minimum Focusing Distance: 100cm / 39.4 inches Maximum Magnification:...

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.

Yes, I would recommend this to a friend

Consistent Output; Lightweight; Sharp Focus; Strong Construction

The build quality of the lens is excellent thanks to high quality materials assembled with very tight tolerances. The broad, rubberized zoom and focus rings operate both very smooth and even slightly damped - a rare characteristic these days.

So which lens you should choose? Sigma 70-200 f/2.8 or Sigma 50-150 f/2.8? First one has better optical performance, especially on APS-C/DX matrix. Astigmatism, vignetting and distortion are well controlled which is not in case of 50-150 model. But all in all advantage of 70-200 is not that big.

poor image quality at the edge for 150 mm; chromatic abberation should be smaller in APO lens; noticable astigmatism for focal length range from 100 to 150 mm; clear vignetting especially at 150 mm; significant front-focus with Canon 20D

This new f/2.8 telephoto zoom from Sigma is the answer to many photographers' prayers. As lenses go, this one is rather short on what you could class as key features, but that doesn't mean that it's below par. In fact it sets the benchmark on what a telephoto zoom should offer.