Tokina at-X PRO 16-28mm F2.8 FX Lens - Nikon AF Mount

The Tokina AF 16-28mm f/2.8 AT-X PRO FX Lens for Nikon  is designed specifically for Nikon pro level DSLRs with a full frame (FX) sensor (such as the Nikon D700 and D3x), this super wide-angle zoom has 15 elements in 13 groups, using aspherical and SD super-low dispersion glass elements to reduce chromatic aberration and give maximum resolution. The silent DC motor allows the lens to focus quickly and quietly and works with a GMR magnetic AF sensor to increase AF speed even more. Features: Silent DC Motor with GMR senor - The 16-28 f/2.8 uses a newly developed silent DC motor that allows the lens to focus faster and more quietly then previous generations. The DC motor coupled with a new GMR magnetic AF sensor work together to increase AF Speed.Ashperical and Super-low Dispersion glass elements - 56mm in diameter, large sizes aspherical glass element is incorporated into the front lens group, while there are 2 more aspherical elements in the rear group. 3 SD super-low dispersion glass elements are also incorporated through-out the optical design to reduce chromatic aberration, give maximum resolution, more even brightness and distortion correction.One-Touch Focus Clutch - Tokinas exclusive One-touch Focus Clutch Mechanism allows the photographer to switch between AF and MF simply by snapping the focus ring forward for AF and back toward the camera to focus manually. There is no need to change the AF/MF switch on Nikon camera bodies and there is no second AF/MF switch on the lens for Canon, everything is accomplished by the focus ring.