A professional-grade 200-400mm f/4 lens with a built-in 1.4x extender that boosts focal lengths to 280-560mm. A four-stop Image Stabilizer maximises sharpness. Instinctive controls enhance handing. Versatile 200-400mm f/4 zoom lens offering superb image quality Zoom range is extendable to 280-560mm with a built-in 1.4x extender An Image Stabilizer allows the use of shutter speeds up to four stops longer than is usual for h&-held photography Built to perform in the toughest situations with magnesium-alloy construction, fluoride coatings & sealing against dust & moisture Fast, near-silent AF tracks moving objects with speed & accuracy, & is accompanied by a full-time manual override & Power Focus for EOS Movies Instinctive placement of controls, including focus-stop & focus-preset switches, for enhanced handling Extendable super-telephoto performance A professional-grade 200-400mm zoom with a constant f/4 maximum aperture. A built-in extender increases focal length by a factor of 1.4x to 280-560mm. Maximum sharpness whatever the conditions Image Stabilizer (IS) technology enables the use of shutter speeds up to four stops longer than normal without camera shake. Three IS modes are available, providing effective performance whilst panning & instant stabilisation only during the moment of exposure. Durable, lightweight construction The use of magnesium alloy adds strength & durability, but not weight. The lens is sealed against dust & moisture & the use of fluoride coatings ensures lens elements are easy to clean. Quick, intelligent focusing Enjoy fast, near-silent autofocus thanks to a ring-type ultrasonic AF motor. Stay in control with full-time manual focus override, & focus-stop & focus-preset controls on the lens barrel. Power Focus is also available for EOS Movies.