Olympus's OM bellows macro — the Zuiko Auto-Macro 38mm f/2.8 for high-magnification close-ups.
The Olympus OM-System Zuiko Auto-Macro 38mm f/2.8 is a bellows macro lens for the Olympus OM mount, introduced in 1983 within Olympus's macro system. It was designed for close-up and high-magnification work on a bellows rather than for conventional focusing, serving technical and nature photographers. It formed part of a family of short macro optics tuned for the OM close-up range.
This is a manual-focus Olympus OM macro lens with a 38mm focal length and a maximum aperture of f/2.8, designated Auto-Macro. Macro lenses of this short focal length are typically used on a bellows to reach magnifications around and above life size with a flat field. The confirmed specifications are the 38mm focal length, the f/2.8 maximum aperture and the manual-focus OM macro design; magnification range, mount thread and weight are omitted here rather than stated without verification.
A 38mm macro sits in the sweet spot for moderate high-magnification close-ups, giving useful working distance and flat-field sharpness on a bellows. It suits insects, flowers, coins, small parts and reproduction work where fine detail must be rendered crisply corner to corner. It is a considered, tripod-based tool rather than a general-purpose lens.
OM bellows macro lenses were made in modest numbers, so this one is uncommon and priced for specialists. Check the glass for haze and fungus, confirm the aperture blades are dry and responsive, and verify that any bellows or adapter mounting hardware is included and correct. Because it does not focus like a normal lens, confirm the mounting method matches your setup. It works on mirrorless for close-up given an appropriate bellows or extension arrangement.