Ultra-Wide Range. On a full-frame camera, the 12-24mm’s zoom range is wide. Like really wide. We’re talking a field of view that ranges from 122° at the widest end down to 84.1° at the long end of the range. So it’s good for the usual things wide angles are good for: landscape and architectural photography, or if you want to do your own version of Brazil or 12 Monkeys. The f/4 isn’t super fast, but it’s constant, which makes the lens a good choice for video or stills.

High Build and Image Quality. As a part of Sigma’s Art lens line, this lens goes through Sigma’s rigorous A1 testing to ensure high image quality. The 12-24mm f/4’s optics are quite impressive. There are five “F” Low-Dispersion elements; one Super Ultra Low Dispersion element; and three aspherical elements, including one 80mm aspherical glass element. This glass menagerie works together to minimize spherical aberration, axial chromatic aberration, and field curvature. Super Multi-Layer coating reduces flare and ghosting to maximize contrast. The barrel is made of a lightweight TSC compound that gives the lens a solid, sturdy feel. This lens also offers internal focusing and zooming.

Hyper Sonic Motor Autofocus System. The HSM autofocus system provides fast, smooth, and quiet operation in a wide variety of shooting situations. You can also manually override the autofocus motor at any time by rotating the focusing ring, giving you quick fine-tuning ability.

Dock Compatible. As part of Sigma’s Global Vision series, this lens is compatible with the Sigma USB Dock for Canon EF Lenses (separate rental item), allowing you to adjust certain parameters through the Sigma Optimization Pro software.