Tokina AT-X 28-70mm f/2.6-2.8 Pro II is an exceptionally fast standard zoom lens with razor sharp optics and constant lens speed for most autofocus 35mm SLR cameras. This unique lens does not change its physical length when zooming. The inner lens tube moves, but never protrudes beyond the filter thread. The internal focusing combined with Focus Clutch mechanism, yields quick and silent autofocusing and smooth manual focus. The lens also features enhanced multi-coating and High Refraction Low Dispersion glass to improve contrast while reducing flare and ghosting. In addition, the lens features 16 elements in 12 groups, eight blade diaphragm, 75.3-34.3° viewing field, 0.7m close focusing distance, 77mm filter thread and bayonet mount hood.