Zeiss Contax 28mm f/2.0 Distagon cinemodded EF-Mount, declicked iris, 0.8 gears for iris and focus, 80mm front with 77mm thread, fullframe coverage, 760 gr Faster than the “little” brother this lens starts at a f/2.0 with the unique vintage look of a mid 90ies Zeiss lens. 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.