This compact wide-angle zoom has a bright constant f/4 aperture make viewing and auto focus possible in lower light situations but still maintaining a reasonable size and weight.
Aspherical and Super-low Dispersion glass elements
Two Super-Low Dispersion glass elements and one aspheric glass allow the proprietary optical design to achieve excellent contrast and sharpness as well as controlling chromatic aberration.
One-Touch Focus Clutch
Tokina’s 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 lens mount for manual focusing.
Additionally the mechanics have been designed for better seals around moving parts making the lens more water-resistant than lenses of the past. The lens is also designed to stand up to the rigors of daily use by photographers in a wide variety of shooting conditions and environments.