Canon e dioptric lenses provide near and far sighted users with a clear viewfinder image without wearing spectacles canon dioptric lenses only handle simple eyesight defects of long and short sight they may not help other eyesight problems for the eos 300d 350d 400d 450d 500d and 1000d the rubber eyepiece frame ef is required for the eos d30 d60 10d 20d 30d 40d 50d and 5dmkii the rubber eyepiece frame eb is required for the 1dmkiimkiin and 1dsmkii the rubber eyepiece frame e