Sigma 28-135mm f/3.8-5.6 — manual-focus travel zoom spanning wide-angle to telephoto.
The Sigma 28-135mm f/3.8-5.6 was a manual-focus travel zoom from the mid-1980s, extending Sigma's wide-to-telephoto range further than the contemporary 28-105mm for photographers wanting one lens to cover most everyday shooting.
Spanning 28-135mm with a one-touch push-pull zoom and manual focus ring, it used a variable f/3.8-5.6 maximum aperture and an all-metal manual-era barrel. Sigma offered it across fittings including Pentax K, Canon FD, Nikon F, Minolta MD, Olympus OM, Konica AR and Contax/Yashica mounts.
The extended range comes at the cost of maximum aperture and edge sharpness at the long end, with the lens performing best in the middle of its zoom range and softening noticeably wide open at 135mm.
Secondhand prices are low, often sold alongside older film bodies. Check the extending zoom barrel for play, confirm smooth manual focus travel, and inspect the glass for haze or fungus common in decades-old Sigma zooms.