The Pro-300 2x DG in Canon EOS fit is a top quality multicoated converter designed for use with lenses of 100mm or longer (on 35mm format) and autofocusing with lenses of f4.5 or faster. The converter uses multicoated low dispersion Hoya glass to achieve excellent sharpness even at full aperture. Metal body and chrome metal mounts assure rigid connection between lens and camera.