MC Helios-81N 2/50 with the logo of the Arsenal plant compatible with the bayonet mount
manual focus only.
aperture control ring, as well as semi-automatic aperture control using the aperture ring and aperture pusher of cameras that have one.
MS - multilayer educational optics.
The lens is suitable for full-frame cameras (analogue of modern Nikon FX cameras).
metal case
lanthanum glasses in the optical scheme