Canon EOS fit Vivitar 55mm Macro lens. This lens has a M/SR Mount to which an EOS Adaptor mount has been added, meaning it can be used on ALL Canon EOS Film and Digital SLR's. The adaptor does NOT have a glass element in situ so the lens will ONLY focus on objects close to the camera, it will not focus on anything beyond about 1 foot away - but its a Macro lens so its totally irrelevant.
The Albinar Catadioptric or Reflex Mirror Lens is a highly developed computer designed product, using the merits of both reflex optics and refraction optics. ND 2X and ND 4X ( Neutral Density ) : This filters control the light passage since no diaphragm system is provided in the reflex lens.
In addition, AF operation is maintained on most cameras when the attached lens has an aperture of f/3.5 or faster. This means F1 - F3.5. If the aperture is slower, the in-focus lights will work but focusing must be done manually.