"The EF100-400mm f/4.5-5.6L IS II USM is compact size, wide zoom range for versatile scenes, and high-speed precision lens that is well-suited for many genres of photography including aviation, sports, and nature. With the use of one fluorite lens in conjunction with a super UD (Ultra Low Dispersion) lens, chromatic aberration is reduced and this results in outstanding image quality across its entire range of focal distances. The EF100-400mm f/4.5-5.6L IS II USM also features a significantly enhanced IS (Image Stabilization) unit to deliver sharp and clear images in a variety of situations. The camera's new IS unit provides an IS performance improvement from 1.5 steps to 4 steps and three different modes of optimal stabilization. Filter size: 77mm Max aperture: f/4.5 - 5.6 With ring USM motor and IS"