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.