Canon EF 200-400mm f/4L IS USM Extender 1.4x High performance L-series super-telephoto zoom with built-in 1.4x extender (280-560mm, f/5.6) makes it ideal for sports and wildlife photography One fluorite and four UD lens elements provide excellent correction of chromatic aberration throughout the entire zoom range, delivering high-quality images with high resolution and contrast Inner focusing, ring USM, a high-speed CPU and optimized AF algorithms for fast and accurate autofocusing Optical Image Stabilizer provides up to four shutter speed stops of correction. Three image stabilization modes (standard, panning, and during exposure only) provide excellent results for a wide range of shooting situations