Tokina AT-X 17mm f/3.5

Manufacturer's Description:

"Ultra wide-angle lens features HLD (High refraction Low Dispersion) glass elements created by Hoya exclusively for Tokina, as well as an all-glass molded aspherical lens element that creates a more compact optical design and provides even illumination across the whole film plane. The floating element system maintains high resolution and contrast for digital SLR or film cameras.

The lens has a Focus Clutch Mechanism for faster, smoother autofocus and, smoother, more precise manual focus. Its barrels are all aluminum with a chrome plated brass mount plate. "