Tamron's new SP AF 17-50mm F/ 2.8 acts RDI II VC covers the heavily used 17-50 MM focal distance range (angle of view equivalent of 26-78 MM when converted to the full frame format) making it an extremely versatile, high performance zoom lens. Achieving sharpness and striking contrast, the lens produces beautiful images that are enhanced by the shallow depth of field afforded by the maximum aperture F/2.8 and enriches the users range of photographic expression. The new lenses equipped with Tamrons proprietary vibration compensation (VC) image stabilization mechanism, which provides more opportunities for handheld photography, such as low light conditions like evening, night scenes and indoors, leading to dramatically enhanced level of photographic freedom. Technical specifications: focal length 17 - 50 MM: format size APS C: maximum aperture F/2.8; minimum aperture F/ 32; diagonal angle of view 78 degree and 45 minute - 31 degree and 11 minute; lens construction 19 elements, 14 groups; minimum focusing distance 11.4-Inch (0.29m); maximum magnification ratio 1:4 0.8; filter diameter 72 mm; overall length 3.7 inches maximum diameter 3.13 inches; weight 20.15oz. 570g; diaphragm blades-seven; standard accessory flower shaped lens hood; Canon mount.