Vivitar — 100-300mm f/5.6-6.7 budget telephoto zoom, sold across several 1980s SLR mounts
Vivitar's 100-300mm f/5.6-6.7 was a budget consumer telephoto zoom from the 1980s, offering extended reach for SLR owners who wanted wildlife, sport and travel telephoto coverage without the cost of a fast professional zoom. It sat firmly in the brand's entry-level long-zoom category.
It is a manual-focus zoom with a modest variable maximum aperture running from f/5.6 to f/6.7, coupled to an automatic diaphragm for open-aperture metering. Like other Vivitar zooms of the period, the design was manufactured in several interchangeable SLR lens mounts.
The slow variable aperture limits handheld use in dim light and through many viewfinders of the period the image dims noticeably at the long end, so it favours bright outdoor use. Sharpness is workable in the mid-range of the zoom and softens toward 300mm, typical of budget long zooms.
These lenses are common and cheap secondhand, often showing haze or fungus from long storage given their low original cost. Check the front and rear elements with a torch, confirm the zoom and focus rings move freely, and verify the mount fitted matches the camera system before buying.