An updated classic, designed for more intuitive and interactive use, the Canon EF-mount Tokina atx-i 11-20mm f/2.8 CF is an ultra-wide zoom that is ideal for landscape, architecture, interior, and astrophotography applications. Its bright f/2.8 constant maximum aperture affords consistent brightness throughout the zoom range and benefits working in available lighting conditions. The optical design incorporates a series of aspherical and low dispersion elements, which suppress a variety of aberrations for improved sharpness and clarity. Individual elements are also multi-coated to resist flare and ghosting for greater contrast and color accuracy when working in bright or backlit conditions. Complementing the optics, this lens features a One-Touch Focus Clutch Mechanism for fast changing between AF and MF settings, and an internal focusing design is used for responsive focusing performance.