This Nikon 85mm f2 Nikkor is a portrait lens with a fast f2 maximum aperture. This is a great lens for low light or shallow depth of field photography and is an ideal focal length for close portraiture.This lens has the AIS variant of the Nikon F lens mount. It is NOT backwards compatible with Non-AI Nikon cameras, as it lacks the necessary flange to index apertures.This lens has a 52mm filter thread.