Zeiss Contax 15mm f/3.5 Distagon cinemodded EF-Mount, declicked iris, 0.8 gears for iris and focus, fullframe coverage, 1070 gr A wide-angle lens with a little barrel distortion but the unique vintage look of a Zeiss lens. Because of the angle of view the use of a clip-on mattebox is not possible. If a ND is needed use either the internal camera NDs (if available) or use a adapter with build-in variable ND. This lens may not be used with a 0.71 speed booster or any other speed booster due to opto- mechanical reasons means danger to damage lens or speed booster.