Canon-compatible camera lens features bright f/5.6 aperture at 400mm Smallest SLR lens available that zooms to 400mm Camera accessory includes smooth internal focusing system Lens mates with 72mm lens filters All-metal inner barrel houses the heaviest glass elements and does not rotate as lens focuses New coatings applied to elements are formulated to compensate for highly reflective sensors in today's digital SLR cameras Built-in low-profile tripod collar makes for a well-balanced camera/lens combination when using a tripod or monopod Zoom can be locked at 80mm, eliminating zoom creep when camera and lens are being carried