Image Stabilizer technology to reduce the effect of hand held movement, with 2 modes for panning and static shooting Ring Type USM for high speed, silent autofocus Fluorite and 2 UD optical elements deliver superior optical performance.
The lens of choice for sports and wildlife photographers Super telephoto L-series lens with an Image Stabilizer for use in track and field sports as well as low-light nature and wildlife photography. The fluorite element and two UD-glass elements result in high resolution and high contrast. The ring USM and an improved AF drive algorithm make the AF speed the fastest in the world when used with the EOS-1v and EOS-3. This lens has the same AF stop and focus preset features as the EF 300mm f/2.8L IS USM.