The Canon EF 200mm f/2.8L II USM Autofocus Lens uses a rear-focus telephoto optical design with two ultralow-dispersion (UD) glass elements to ensure maximum image sharpness and accurate color fidelity. The two UD glass elements, combined with the rear focusing, correct aberrations to give you extremely sharp and clear images. This lens is perfectly suited for Canon's EOS system cameras--placing special emphasis on its manual focusing capability--which have a wide rubber focusing ring that allows you to make easy adjustments. The ultrasonic motor (USM) and rear focusing design allow for silent, high-speed autofocus and full-time manual focus. Because of its full compatibility with 1.4x and 2x EF extenders, you have the option of added focusing versatility. Features EF mount; telephoto lens Ultra-low Dispersion glass with Fluorite elements; inner focusing ring; full-time manual focus 200mm focal length f/2.8 maximum apertureMicro UltraSonic Motor (USM)