I've seen the review here which mentions Chromatic Aberration / Purple Fringing being not too well-controlled, but try as I might, I am unable to make this lens produce significant visible evidence of CA . I'm testing it on an EOS 80D, shooting RAW, Adobe Color Space.

Convenient focal-length range for a go-to carry-everywhere lens; Excellent sharpness throughout, Well-controlled CA, Silky feel to the zoom ring, No front-element rotation during A/F, Looks great, Light and compact, but not too light

No manual-focus over-ride; Focus ring rotates during A/F

I purchased this lens to replace my standard kit lens that was originally included when I purchased my camera. I can say that after testing the new lens that I am well impressed by the build quality and the resolution of the pictures that are sharp in colour and clarity.

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

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...

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

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...

I bought this lens primarily for low light use since I like to shoot at night. So far so good. I have not critically tested the sharpness but casual observation indicate good resolution although not as good as the Nikon lenses. Mechanically it works great.

Consistent Output; Durable; Easily Interchangeable; Fast / accurate auto-focus; Lightweight; Strong Construction

The 17-70mm f2.8-4.5 DC Macro AF (Auto Focus) is Sigma's first digital only macro lens.

Sharp, fast, contrasty; Bargain price for its overall capabilities

Drag on the manual focus ring