Nikon's compact mirror super-tele — the manual-focus Reflex-Nikkor 500mm f/8, ring-bokeh catadioptric.
The Reflex-Nikkor 500mm f/8 is a mirror (catadioptric) super-telephoto for the Nikon F system, introduced in the late 1960s. Reflex designs use curved mirrors as well as glass to fold the light path, so the lens is far shorter and lighter than a refractive 500mm would be. It gave F-system photographers long reach in a compact, if fixed-aperture, package.
This is a manual-focus Nikon F lens with a fixed f/8 aperture and a 500mm focal length, built as a catadioptric mirror lens. Because mirror lenses have no adjustable diaphragm, exposure is controlled by shutter speed and ISO or by neutral-density filters, often fitted at the rear. Only the verified focal, aperture and mount are stated; further specifics are omitted.
The defining trait of a mirror lens is its ring-shaped bokeh, where out-of-focus highlights render as bright doughnut rings due to the central obstruction. Contrast is lower than a refractive tele, but the reach and compact size are the draw. It suits wildlife, sport and distant subjects where portability matters more than the fixed aperture.
On the used market the Reflex-Nikkor 500mm f/8 is collectible and fairly common, valued for its light weight and characteristic look. Inspect the mirror surfaces and elements for haze, fungus and coating loss, confirm the rear filter is present, and test the focus for smooth action. It adapts well to mirrorless, where its compact reach and ring bokeh remain distinctive.