Lens2scope 10mm 1:4 Eyepiece for Canon EF/EF-S Lens, Angle View, Black Color 10mm 1:4 eyepiece for Canon EF/EF-S mount lens 42 degree apparent field of view with angled observation view 20mm long eye relief with foldable rubber eyecup for eyeglass observation Convert a telephoto lens to a spotting scope, or a macro lens to a long working distance loupe Detachable tripod mount design ; Fast Release metal lens mount Prism System : Roof prism