The Canon EF 100 mm F/2.8 Macro USM Lens with autofocus provideslife-size magnification to help you capture crystal-clear picturesof faraway objects. The inner focussing system provides a workingdistance of up to 5.9 inches. This Canon USM lens features the 3-groupfloating system to help you take great close-up shots. The attachedsecondary diaphragm increases the contrast in photos by blockingout unwanted light at f/2.8. This 100 mm macro lens integrates anultra-sonic monitor to ensure outstanding autofocusing speed at allfocusing distances. The lens lets you adjust the focus manually withthe wide and smooth manual focus ring.