The 12-28mm f/4.0 AT-X Pro APS-C Lens for canon from tokina is a wide-angle
to standard length zoom lens with a maximum aperture of f/4.0. It is compatible
with canon APS-C cameras and affords a 35mm focal length equivalency of
19-45mm. 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 affords incredibly fast, accurate AF. The lens' SD-M (Silent
Drive-Module) means that autofocus responds smoothly and silently, which is
ideal when shooting HD video.