Its extremely wide-but-usable perspective is complemented by the f/1.8 maximum aperture for excellent performance in low-light conditions and increased control over depth of field. The optical design incorporates two extra-low dispersion elements and one super ED element to reduce chromatic aberrations, plus two XA (extreme aspherical) elements that significantly control spherical aberrations for a high degree of image sharpness and clarity. A Nano AR II coating has been applied to limit ghosting and lens flare for increased contrast and color fidelity when working in strong lighting conditions.

An XD Linear Motor system uses two separate motors to provide quick and quiet focus, and also lends more responsive control for manual focus operation. A minimum focus of just 9.8" and an ultra-wide field of view opens a new world of deep perspective close-up photography. Also, the lens features a dust- and moisture-sealed design and fluorine-coated outer elements to support shooting in inclement conditions.