Great lens, compares very favorably to my Canon 17-40 that cost much more. The set 3.5 is great! There is very little distortion (bulging/curving) and good sharpness even at edges. As long as you keep the camera level, all verticals remain straight.

Sigma's original 10-20mm f/4-5.6 ticked pretty much all the right boxes, and rapidly became a top seller for users of Canon, Nikon, Olympus, Pentax, Sigma and Sony bodies alike.

I bought it instead of Sigma 10-20/4.5-5.6 with good discount price. For such price very good wide zoom lens for crop cameras. When buy try to check a few copied due bad Sigma quality control. My copy is really perfect. For higher price check Tokina 11-16/2.8, but for me zoom range is not enough

Fast and accurate focus; Sharp in center even open at 3.5 at 10 mm; Very reasonable sharpness in corners after 7.1; Overall picture quality better compared to Sigma 10-20/4.5-5.6 and Sony 11-18/4.5-5.6

Some CA at 3.5 in corners; No after 4.5; Could be less distortion in corners at 10-12 mm

This Sigma wide-angle comes in at a very reasonable price for what it is and for its features. It's also available for plenty of lens mounts. This lens is considered by some photographers as the benchmark for APS-C wide-angles, though our tests suggest this may not now be the case.

"I love this lens! I recently purchased and used it with my Nikon D5100, and I was awestruck by the results. I'm going to now begin with the comment(s) most people look for: ****** CONS ******.

Sharp images across it's range. Quality build. Worth every cent...

Although I can't compare this to other UWA lenses I can compare it to other zoom lenses I have (such as Sigma 17-70) and this lens beats them hands down. Feel and build quality is excellent. HSM focussing is wonderful. Flare resistance is surprisingly good for a UWA.

Very sharp center; nice feel; good auto focus; very useful range

Corners at 10mm could be sharper

I have just recently bought this lens and it is fantastic. It is amazingly crisp and works a treat. Highly recommended.

xcellent. Wide Angle,Very sharp and fast and for low lite.

These Sigma 10-20mm F3.5 is my first Lens from Sigma; Absolutely very sharp in my 7d camera it gives me an outstanding color and a wide angle in a tight space.

They should make it zoom

This lens is more than I ever expected. The focal lengths are perfect for property photos and a fast lens correction in Lightroom puts everything into place. I love the fixed 3.5 and the 10mm. I have no problems with the SB800 flash providing enough light and coverage.

Consistent Output; Fast / accurate auto-focus; Lightweight