When you consider its price, it's hard to argue with the value that the excellent Sigma 17-70mm F2.8-4 DC Macro OS HSM ($499) delivers. Its aperture is wider than the run-of-the-mill 18-55mm f/3.5-5.6 zoom lens that ships with most entry-level D-SLRs, and it covers both a wider and longer field of...

Sharp; 4.1x zoom range; 1:2.9 macro magnification; Optical stabilization; Wide aperture; Compact and light; Available for multiple camera systems; Compatibility with Sigma USB dock and mount conversion service

Some distortion; Edge softness at 70mm

Former professional photographer looking for a "walking around lens". Something to keep on my Canon 7D (or any crop sensor camera) for most shooting situations. The expanded focal length at the wide end (17mm vs 24mm) is perfect for crop sensor cameras.

Wide focal length

The Sigma 17-70mm F2.8-4 DC Macro OS HSM is designed as an upgrade to the 18-55mm kit lenses supplied with most SLRs, and offers an interesting middle ground between fast zooms of the 17-50mm F2.8 type, and extended-range zooms in the 16-85mm class.

Useful combination of zoom range and relatively fast aperture; Very good image quality across most of the range; Compact size; Reasonably fast and near-silent autofocus; Effective image stabilisation

Somewhat weak image quality at wideangle (soft corners and chromatic aberration; Macro shooting a little impractical (very short working distance

Sigma's 17-70mm f/2.8-4 DC Macro OS HSM lens is an upgrade to the AF 17-70mm f/2.8-4.5 DC Macro lens released in 2006. Designed for the smaller imaging circle of cameras with APS-C sized sensors, it is slightly larger and heavier than its predecessor and has a more complex optical construction.

You want an affordable general-purpose lens to replace a standard kit lens, You'd like a lens that requires no readjustment when you fit polarisers and graduated filters; Don't buy this lens if, You require a lens with excellent flatness of field and edge-to-edge sharpness, You need true macro...

Since I was very pleased with the Sigma 30mm 1.4 EX and 180mm macro EX, I bought this lens second hand to see if it could replace my good old but dying EF 24-85 3.5-4.5 USM (own Canon 10-22, 70-200L f:4, 100-400L, 400L 5.6, 60 2.8 macro, 18-55 IS kitlens, use also 17-40L and 50 1.4).

fast and correct AF; good image stabilisation; sharp on wide angle at f:2.8; short focus distance

not sharp at f:4 on the long side; big and heavy; yellowish color tone compared to Canons

With so much to talk about in this lens it would be easy to miss something important, such as the fact that it offers a bright f/2.8 aperture at 17mm. This is an amazing achievement that is all the more remarkable given the zoom's 4.1x focal-length range.

Great all-round lens

Non-internal focusing

This digital-only lens boasts excellent performance, Optical Stabilisation and a rock bottom price tag - so is there anything not to like?

Great all-round lens

Non-internal focusing

This lens exceeds my expectations (based on reviews that I read online) on all aspect, it is both fast and sharp. the provided lens hood is also a bonus. quite heavy though but that should be fine because you'll be getting higher quality photos compared to any standard kit lenses (I was using...

The wide F2.8 aperture and image stabilisation has has allowed me to do some no-flash indoor work without using a tripod.

Hands down best lens for the money. While it's not Nikkor, it is also not over $1k. When my original lens broke after 4 years of abuse (I live in East Africa) I replaced it with a different Sigma. After not getting the same quality shots I bought this one again.