Vivitar — 70-210mm f/4.5-5.8 manual push-pull telephoto zoom, sold across many SLR mounts
Vivitar was a marketing brand that commissioned Japanese optical houses to build lenses sold under its own name through independent camera stores. This 70-210mm push-pull zoom sat in Vivitar's budget telephoto range of the late 1970s and 1980s, aimed at SLR owners moving up from a standard 50mm kit lens.
It is a manual-focus, one-touch push-pull zoom with a maximum aperture running from f/4.5 at 70mm to f/5.8 at 210mm, and a macro-focus switch near the long end. It was produced across most manual-focus SLR fittings of its era. Element count, weight and filter size for this variant are not confirmed.
As a variable-aperture, non-Series-1 design it favours compactness and low price over the brighter constant apertures of Vivitar's Series 1 telephotos; sharpness is workable stopped down but softer wide open toward the 210mm end, with contrast improving from around f/8.
It trades for modest prices on the used market today, reflecting its original entry-level position. Worth checking: smoothness of the push-pull action for grease creep or grit, clean engagement of the macro detent, and the elements for haze, common in decades-old budget zooms.