The Tamron SP AF17-50mm f/2.8 XR Di II LD Aspherical [IF] is a lightweight, compact, fast standard zoom lens designed exclusively for digital SLR cameras. The focal length of this lens is equivalent to approx. 26-78mm in 35mm format. This lens offers an f/2.8 maximum aperture throughout the entire zoom range, to ensure stress-free photographic shots at all focal lengths and distances. Additionally, a broader photographic expression through the use of faster shutter speeds as a result of the maximum aperture offers enhanced photographic pleasure .