A 400mm super telephoto lens with a first-rate imaging performance, plus Image Stabilization effective over two shutter speeds. The image stabilizing mechanism used on IS lenses provides high-speed correction control whenever vertical or horizontal movement is detected, allowing for a greater range of hand-held photography and sports photography performed indoors or at night. The optical system includes one fluorite and two UD lens elements that eliminate secondary spectrum, for ultra high contrast and image quality. With a ring-type USM and an improved drive algorithm, its autofocusing is the fastest in the world*¹. The closest focusing distance has been reduced to 3m / 9.8ft., and it is equipped with full-time manual focus that does not consume electric power. It has both focus preset and AF Stop functions. This lens is lightweight due to the use of a magnesium alloy for its barrel and other external parts. It offers superior dust-proof*² performance even under harsh conditions.