Olympus's OM high-magnification macro — the Zuiko Auto-Macro 20mm f/2 for bellows close-up work.
The Olympus OM-System Zuiko Auto-Macro 20mm f/2 is a high-magnification bellows macro lens for the Olympus OM mount, introduced in 1983. It was part of Olympus's respected macro system, designed for extreme close-up work at magnifications well beyond life size rather than for general photography. It reflected the OM system's strong reputation in scientific and technical imaging.
This is a manual-focus Olympus OM macro lens with a 20mm focal length and a maximum aperture of f/2, designated Auto-Macro. Short-focal macro lenses of this type are used on bellows or extension systems to reach very high reproduction ratios. The confirmed specifications are the 20mm focal length, the f/2 maximum aperture and the manual-focus OM macro design; magnification range, mounting thread and weight are omitted here rather than asserted without confirmation.
A 20mm macro of this kind is a specialist optic for photographing small subjects at greater than life size, revealing detail invisible to the eye. It is used with bellows and focusing rails for insects, minerals, electronics and laboratory subjects where high magnification and flat-field sharpness matter. It is not a walk-around lens; its whole purpose is controlled, high-ratio close-up work.
These dedicated macro optics were made in small numbers and are scarce on the used market, so they command high prices among specialists. Check the glass for haze and fungus, confirm the aperture blades move cleanly, and verify any bellows or adapter mounting hardware is present and correct. Because they lack a normal focus helicoid, confirm how the copy is intended to mount. They adapt to mirrorless for high-magnification work given the right bellows or tube setup.