The heliar 40mm f28 is an all metal prime lens with leica m mount however it has been manufactured to function as a close focus lens for use on sonys full frame and aps c e mount cameras via the vm e close focus adapter not included available separately the lens offers a bright f28 aperture and a close minimum focusing distance of 05m the lens does not have a built in focusing helicoid and focusing is done by rotating the helicoid of the vm e adapter