The Sigma 17-50mm F2.8 EX DC OS HSM ($980 list) is a standard zoom lens for APS-C cameras . Like most Sigma lenses, it's available in a variety of lens mounts-Canon, Nikon, Sony/Minolta, Pentax, and Sigma in this case.

Soft wide open

Gary Wolstenholme takes a look at Sigma's flagship standard zoom for APS-C digital SLR cameras. Sigma's 17-50mm f/2.8 EX DC OS HSM costs around ￡590 and is available for Sigma, Canon, Nikon, Sony and Pentax SLR cameras that have an APS-C or smaller sized sensor.

Excellent performance in the centre between 28 and 50mm when stopped down; Effective Optical Stabiliser; Compact and lightweight for an f/2.8 zoom

Lens really needs stopping down for best results; Sharpness towards the edges; Focus ring cannot be disengaged

The Sigma 17-50mm f/2.8 EX DC OS HSM Lens features a nice range of focal lengths, a wide f/2.8 aperture, HSM autofocus and OS (optical stabilization) in a well-built and reasonably-priced lens.

Digital-only speedsters in the 16–55mm range are at home in the Canon, Nikon, Pentax, and Tamron catalogs. All offer fast f/2.8 constant apertures and image stabilization (except for the Pentax, which puts IS in the camera).

When it comes to DSLR image quality, pretty much all of us have heard the old truism about the quality of the lens being more important than the price of the camera. In this respect it pays to get off to the best possible start when buying your first DSLR, or when taking your first steps towards...

Constant aperture of f/2.8; Smooth zooming action; Delivers excellent results

Manual focus ring is fiddly; All-plastic outer construction; Resolution tails off above f/11

A compact standard zoom lens for APS-C digital SLRs from Sigma with a bright constant f/2.8 aperture, optical stabilisation and a silent focusing motor.

Excellent performance in the centre between 28 and 50mm when stopped down; Effective Optical Stabiliser; Compact and lightweight for an f/2.8 zoom

Lens really needs stopping down for best results; Sharpness towards the edges; Focus ring cannot be disengaged

As far as build quality is concerned, the Sigma 17-50mm f/2.8 EX DC OS HSM is very sturdy, with a rigid zoom barrel that doesn't need much rotating to go through all the focal lengths.

You might think this is the lens to get, and you might be right. It gets lots of great praise across the internet, so why not get it It comes in the mail and you love it, works like a charm and produces great pictures.... oh wait, whats that Why is the right side so blurry

Cheap; Has OS that works pretty well; Seems like a good copy would be very sharp; has switches on the body to turn off OS and AF

Lens comes included with terrible QC, good luck getting a copy that isn\'t decentered to some degree AND doesn\'t have a broken AF motor out of the box; It will never focus as well as a Canikon lens; Doesn\'t work well with outer focusing points, making them useless.

The Sigma AF 17-50mm f/2.8 EX DC HSM OS is a highly competitive APS-C standard zoom lens and Sigma's best product in this class so far. It's not a flawless lens but none really is.

I wanted a fast normal zoom to use with my D300. Based on the many reviews online it was easy to narrow my decision down to two choices, the Nikon 17-55 f/2.8 or the Sigma 17-50mm f/2.8. I decided to get the Sigma since it was half the price of the Nikon and had VR.

Lighter, Less Expensive than the Nikon option; Generally very good overall sharpness and excellent in the center.

Corner softness at f/4 or less when wide