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This 500mm super telephoto lens with Image Stabilizer system and large aperture of f/4 is sure to have wide appeal. Its newly designed optical system consists of 17 elements in 13 groups, including one fluorite lens and two UD lenses. These have eliminated all kinds of aberrations to achieve a level of image quality previously impossible to attain. With ring USM and an improved drive algorithm, its autofocus is the fastest in the world (when used with the EOS-3).