Extremely compact and light for an IS lens, it has a plastic mount and barrel with a small focus and a much larger zoom ring. Turning actions are well-damped by kit lens standards. Zoom settings are marked in large, easily legible numerals, and the MF/AF and IS switches have contrasting ribbing, so each can be identified by touch. On our Digital Rebel XTi test body, AF action was fast, accurate, and surprisingly quiet. At slightly over 3 inches, racked out, the lens casts no shadow when used with the XTi's flash.