Minolta's mirror super-tele — the RF Rokkor 1000mm f/6.3 catadioptric, a rare 1960s specialist.
The Minolta RF Rokkor 1000mm f/6.3 is a catadioptric mirror manual-focus lens for Minolta reflex cameras from the mid-1960s. RF denotes its reflex (mirror) construction, which folds a very long optical path into a compact barrel using mirrors as well as glass. It was a specialist super-telephoto for extreme reach, used for astronomy, distant wildlife and surveillance-style work.
This is a manual-focus catadioptric super-telephoto with a 1000mm focal length and a fixed maximum aperture of f/6.3, typical of mirror lenses which have no adjustable diaphragm and control exposure by shutter speed and ND filters instead. Only the focal length and aperture are stated as verified; other construction data for this rare lens is not confirmed and is omitted.
The enormous 1000mm reach makes distant subjects fill the frame, suiting the moon, far-off wildlife and heavily compressed scenes. As a mirror design it renders out-of-focus highlights as characteristic rings or doughnuts, and its fixed aperture and long focal length demand a sturdy tripod and careful technique for sharp images.
On the used market this is a rare and heavy collector's item rather than an everyday lens. Because of its mirror construction, check the front and internal mirrors and glass for haze, fungus and separation, confirm the focus mechanism moves smoothly, and inspect the tripod mount. Verify it comes with any rear filters, since mirror lenses often rely on them for exposure control.