Fast maximum aperture telephoto lens optimized for digital SLR cameras. This telephoto lens has a fast maximum aperture, & also features a new super multi-layer coating, which optimizes the characteristics of digital SLR cameras. A versatile, fast aperture telephoto lens for both digital & film SLR cameras. Two ELD glass elements reduce chromatic aberration to a minimum & also ensure sharp, quality images of high contrast. The new multi-layer lens coating reduces flare & ghosting, a common problem with digital SLR cameras. The Internal Focus system ensures the overall length of the lens does not change during focusing, ensuring convenient handling & ease of use. The HSM (Hyper Sonic Motor) models provide fast, silent AF function as well as full- time manual focus override. A drop-in 46mm filter holder in the rear part of the lens barrel can be rotated to facilitate the use of filters, including a polarising filter, in situ. Simply adding an APO teleconverter (optional extra), means that this lens can be used as a 420mm F4 AF ultra-telephoto lens with a 1.4X EX teleconverter, or a 600mm F5.6 AF ultra-telephoto lens with a 2X teleconverter.