The Tokina 12-24mm f/4 AT-X 124AF Pro DX II Lens is exclusively designed for use with SLR cameras that use Canon's DX format (APS-C size). In addition, this updated "II" version incorporates a motor built into the lens itself, which gives it the capability to autofocus with all Canon DSLR cameras, including the D40 and D60 series. Another benefit of the built-in motor is that focusing is quieter and more responsive. This lens provides a super wide-angle zoom range, ideal for the tightest of interiors, as well as for dramatic landscape photography. This 12-24mm f/4 AT-X version II lens also benefits from improved multi-coating technology, which helps to reduce reflections that can cause flare and ghosting. The Focus Clutch Mechanism feature - a signature of Tokina Pro series lenses - provides a faster, smoother autofocus operation, with a smooth manual focus action not normally found in autofocus lenses. Two Aspherical elements are incorporated in the lens design, to correct for spherical aberrations. It also incorporates internal focusing to prevent deterioration of the optical quality at close distances and to eliminate rotation of the front barrel during focusing. Equivalent focal length in 35mm terms when used on a digital camera is 18-36mm. Note! DX lenses are NOT recommended for use with "full-frame" FX digital or 35mm film SLR cameras. Fast, ultra-wide angle zoom lens with a constant f/4 aperture Two aspherical lens elements minimize distortion, especially at the periphery, for superior optical performance Fast internal focusing with the one-touch Focus Clutch Mechanism Long focus travel for easy, accurate manual focusing The rounded diaphragm opening (9 blades) makes out-of-focus elements appear more natural   Filter Size 77mm f/Stop Range f/4-22 Minimum Focus Distance 11.8" (0.3 m) Magnification 1:8 Zoom/Focus Control Rotary-type zoom / Two-touch Angle of View 99 to 61° Groups/Elements 11/13 Lens Coating Multi-layer Number of Blades 9 aperture blades Length 3.5" (90mm) Maximum Diameter 3.5" (84mm) Weight 1.2 lb (540g)