This ultra-wide angle zoom lens from Sigma projects an image circle big enough for full frame digital/35mm and is still very wide on a cropped sensor. We take a look at how it performs.

Enormous field of view; Amazing control of distortions; Solid build quality with good protection of front element

Difficult to use front mounted filters (Though not impossible; Bulbous front element needs careful handling

Sigma 12-24mm f/4.5-5.6 EX DG HSM is one of about half a dozen ultra wide zoom lenses in Sigma's modern lens lineup. This is also one of the widest full-frame zoom lenses available on the market at this time (there are a couple of 'wider' APS-C type lenses offered by Canon, Tokina as well as Sigma...

The Sigma 12-24mm F4 DG HSM Art is a fantastic ultra-wide-angle zoom lens that significantly undercuts the price of its main rivals whilst offering almost comparable image and build quality. Image quality is excellent.

The Sigma AF 12-24mm f/4.5-5.6 HSM DG II is the only "one size fits all" (formats) ultra-wide zoom lens on the market. It can give you decent results and truly extreme views on full format DSLRs and it is very good along across the more "conventional" zoom range on APS-C DSLRs.

Sigma unveiled its third generation wide-angle zoom lens, the 12-24mm f/4 DG HSM Art lens, on 16 September, just before Photokina 2016. A significant update to the 12-24mm f/4.5-5.6 HSM DG II model, it comes with Canon EF, Nikon F (FX) and Sigma SA mounts.

I used to have a Sigma 15-30 before purchasing this lens, but I needed a larger angle coverage for some architectural pictures. This lens has no real distortion even at 12mm, and it's quite sharp if you use it at f.5,6 and over.

Very wide; Sharp over f.5,6; No distortion at all, a miracle

Needs to be stopped at f.8 and over for the best results