A fast wide-angle zoom for Canon EF mount APS-C-format DSLRs, the At-X 14-20mm f/2 PRO DX Lens from Tokina spans a concise 22.4-32mm equivalent focal length range while retaining a bright, constant f/2 maximum aperture. Ensuring a high degree of sharpness and clarity throughout the wide-angle range, the optical design features an array of aspherical and Super Low Dispersion elements to minimize chromatic and spherical aberrations. A multi-layer, anti-reflective coating has also been added to individual elements to suppress flare and ghosting for increased contrast and color fidelity when working in strong lighting. In regard to handling, an internal focusing design enables quick, accurate autofocus performance that can quickly be overridden for manual control using the One-Touch Focus Clutch Mechanism. Well-suited to working in a variety of situations, the variety of wide-angle perspectives and bright maximum aperture are especially beneficial to landscape, reportage, and other environmental photography applications. Compatible with Canon EF-mount APS-C-format DSLRs, this wide-angle zoom offers a 22.4-32mm equivalent focal length range. Constant f/2 maximum aperture provides consistent performance throughout the zoom range and is well-suited to photographing in low-light conditions. The 13 elements, 11 groups optical design includes one plastic-molded aspherical element, two Super Low Dispersion (Sd) glass elements, and two glass-molded aspherical SD glass elements. This combination of aspherical and low dispersion elements helps to minimize chromatic and spherical aberrations throughout the zoom range for increased clarity, sharpness, and color accuracy. A multi-layer, anti-reflective coating has been applied to individual elements to control lens flare and ghosting for improved contrast when working in harsh lighting conditions. Pairing with an internal focusing design for quick AF performance, this lens also features a One-Touch Focus Clutch Mechanism for switching between AF and MF modes. By sliding the focusing ring back or forth, you can quickly change between focusing modes. Nine diaphragm blades contribute to a pleasing quality of bokeh.