Vivitar — 55mm f/2.8 close-focusing macro prime, sold across several vintage SLR mounts
Vivitar's 55mm f/2.8 Macro was one of the brand's better-regarded close-focusing primes of the 1970s, built by a Japanese optical partner as a budget alternative to first-party macro lenses. It found favour with hobbyists doing close-up and copy work who did not want to pay for a Nikon or Canon macro.
It is a manual-focus prime with an automatic diaphragm for open-aperture metering and a long focus throw that lets it rack in to close-up magnification without extension tubes, extending further with a matched accessory tube. Vivitar produced this optical design across several interchangeable SLR lens mounts.
Optically it is sharp stopped down and holds up well for flat-field close-up subjects, a strength many contemporary zooms lacked. General-purpose sharpness at normal shooting distances is solid but unremarkable, and it doubles reasonably as a standard prime when not shooting close-up.
Clean examples are sought after among vintage macro shooters and command a premium over Vivitar's zooms. Check the long focus throw for smoothness, examine the front element for cleaning marks, and confirm which mount is fitted since Vivitar sold this lens in several fittings.