The Tokina AT-X 14-20 F2 PRO DX is a wide-angle zoom lens with super-fast F2 aperture. This is the fastest lens ever made by Tokina. The lens is designed for use with either Canon or Nikon DSLR cameras with APS-C (DX) sensors. Tokina adds its fastest lens to date to its family of fast-aperture wide-angle zooms focused on providing photographers professional quality optics and construction at an affordable price. The extremely fast F2 aperture lens offers an equivalent 21-30mm** zoom range. The super-bright, constant F2.0 aperture makes viewing, auto focus and shooting possible in very low light situations while still maintaining reasonable size and weight. The 14-20mm F2 has an all-new proprietary optical design that uses three aspherical lens elements (2 all-glass molded and 1 P-MO hybrid) to achieve superior contrast, sharpness, and correct for spherical aberrations. Additionally, Tokina uses of an four SD (Super-low Dispersion, “FK01” and FK03”) glass elements to control chromatic aberrations.