Sigma — 28-80mm f/3.5-5.6 autofocus kit zoom sold across Canon, Nikon, Minolta, Pentax
Sigma's 28-80mm f/3.5-5.6 arrived as autofocus SLRs became mainstream, replacing the earlier 35-70mm class as the default standard-zoom kit option and giving budget-minded buyers a wider starting point than older manual zooms offered.
Zooming from moderate wide-angle to short telephoto, the maximum aperture runs from f/3.5 at 28mm to f/5.6 at 80mm. Sigma sold this optical formula in autofocus mounts for Canon EF, Nikon F, Minolta A and Pentax K bodies, plus its own Sigma SA mount, with a plastic-barrelled, lightweight build typical of 1990s kit-class zooms.
It performs as a competent everyday walk-around lens rather than a specialist tool, with softer rendering at 80mm wide open and noticeably better contrast by f/8. Its light weight and short length make it easy to carry alongside a heavier prime.
Very common secondhand and inexpensive, so condition varies widely. Test autofocus speed and accuracy on the specific mount, check for a wobbly zoom barrel from wear, and inspect the front element for the coating scratches common on cheap kit zooms.