Vivitar — 28-85mm f/3.5-4.5 general-purpose zoom, sold across several vintage SLR mounts
The Vivitar 28-85mm f/3.5-4.5 was a popular general-purpose zoom from the brand's 1980s catalogue, covering wide-angle through short telephoto in one lens as an alternative to a standard 50mm kit prime. It was widely sold as an affordable everyday lens for manual-focus SLR owners.
It is a manual-focus zoom with a variable maximum aperture from f/3.5 at 28mm to f/4.5 at 85mm, fitted with an automatic diaphragm for open-aperture metering. Vivitar produced this optical formula across a range of interchangeable SLR lens mounts to suit different camera systems.
As a moderate-ratio standard zoom it delivers fairly consistent sharpness across its range for a budget lens, with the usual softening toward maximum aperture and the corners. It works well as a walk-around lens for travel and everyday documentary shooting rather than specialist work.
Being one of Vivitar's more common standard zooms, used copies are plentiful and inexpensive. Check the zoom ring for smooth, even travel, confirm the aperture blades operate cleanly, and verify the specific mount fitted, since this lens was sold across several SLR mount options.