The Tamron SP 17-50mm F/2.8 XR Di II VC lens for cropped sensor digital cameras covers the very popular 17-50mm focal length range (equivalent to 26-78mm in the full-frame 35mm format ) making it extremely versatile. Its wide aperture provides practical advantages in low-light shooting and image control, giving you greater creative control. The 17-50mm f2.8 XR Di II VC lens delivers impressive sharpness and contrast over its entire focal-length and aperture range, and at its maximum aperture of f/2.8 produces beautiful images with a shallow depth of- field and smooth, natural out-of-focus areas (i.e. excellent bokeh). The new lens is equipped with Tamron s Vibration Compensation (VC) stabilization mechanism, which controls the effects of camera shake in three planes. The VC function, in combination with the wide maximum aperture, permits sharp hand-held photography, even when shooting in low-light conditions, giving you greater photographic freedom.