The 12-28mm f/4.0 AT-X Pro DX Lens for Nikon from Tokina is a wide-angle to standard length zoom lens with a maximum aperture of f/4.0. It is compatible with Nikon DX cameras and provides a 35mm focal length equivalency of 18-42mm. This compact lens features a one-touch AF/MF clutch operation to switch back and forth between auto and manual focus, for manual focus slide the focus ring back and for autofocus allow to the ring to rest in the forward position. A newly designed GMR (magnetic precision) AF sensor is mounted close to the AF motor and provides fast, accurate AF. The lens' SD-M (Silent Drive-Module) means that autofocus responds smoothly and silently, which is ideal when shooting HD video.