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.

Given the high bar set by Sigma's Art lenses, when I first heard about Sigma releasing this lens at a fairly affordable price I was extremely excited. Unfortunately though, the lens fell short in several aspects.

The Sigma 12-24mm F4 offers impressive optical performance at the short end of its focal range, with excellent AF performance. Unfortunately, central sharpness at all focal lengths, and overall sharpness at the tele end suffers relative to its best peers. Severe focus shift at longer focal lengths require you to focus the lens at the shooting aperture, which can be cumbersome, and will also come at a cost to corner sharpness. Other optical properties, like CA, vignetting, and distortion are extremely well-controlled if not class-leading. If you're looking for a wide-angle zoom with very nice performance from 12mm-16mm then this lens is an exceptional value.

Landscape photographers looking for a wide-angle zoom lens with exceptional sharpness and performance from 12mm-16mm.;

Photographers looking for excellent performance across the entire focal range and photographers who prefer to shoot with a lighter kit;

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.

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.

Ultra-wide lenses are speciality tools that often come with large price tags, especially if you want one that captures sharp detail right to the edge of the frame. The Sigma 12-24mm F4 DG HSM Art ($1,599) is wider than most zooms with full-frame coverage, and about half the price of its closest competitor, the $3,000 Canon EF 11-24mm f/4L USM. It's not quite as wide as the Canon, but competes with it in sharpness, and betters it at the edges. If you want a wide, wide lens for your full-frame SLR it's a stellar performer, and an Editors' Choice pick. Design The 12-24mm ($1,499.00 at Amazon) is a big, heavy lens. It measures 5.2 by 4 inches and weighs 2.5 pounds. You can't use front filters—the front lens element is bulbous—and the hood is integrated into the barrel. Sigma includes a slip-on lens cap, which slides over the hood to protect the lens. Zooms of this type are typically weighty. Wide-angle SLR lenses must be designed to accommodate the mirror box that separates the lens ...

The Sigma 12-24mm F4 DG HSM Art is a full-frame zoom lens with an ultra-wide field of view and f/4 aperture. It's very sharp, and it's less expensive than competing lenses.

Ultra-wide lens with zoom capability; Very sharp; Solid edge performance; Available for multiple camera systems

Big and heavy; Doesn't support front filters; Barrel distortion at wider angles; Dimmed corners at 12mm

I have been using the generation one Sigma 12-24mm lens for wide landscapes and architectual shots for many years. The older lens was sharp in the center but soft at the edges and corners even when stopped down. The older lens was at its worst in the 12-15mm range, right where you needed it most.

I love this lens. I love it for promo photos, realestate , and even group photos. The only thing is I thought o was buying it in Canadian dollars and it ended up being U.S. prices. Ouch.

Agai, lack of Sigma's QC: i bought one second hand, but this lens is a lemon, you can throw it away. The lens was soft overall no matter what i used, really bad till f7.1, from f8 till f22 was overall soft.

nothing

lack of Sigma's QC; lens is soft overall; slow AF

This is the ugliest imaginable lens... Sorry, but had to say that and get it off my chest. It just looks ghastly on my Nikon F5 and on the F100 too. Oh, well, now that I said it, I should add that it's a very good, reliable tool. Where does one get a wide-angle this wide Nowhere!

Speed, size and relatively discreet look (if it wasn't for that front element that's downright bulbous); Nice range of focal lengths

Maybe it's ugliness, along with that the front element is so weird looking and doesn't allow for filters of any type; Other than that, it's not a lens to use with flash 'cuz it vignettes like mad, especially at 12mm (and what's the fun of using a flash at 24mm with this lens None.