Tamron 75-250mm f/3.8-4.5 — Adaptall-2 telephoto zoom (04A/104A), multi-mount fit
Tamron's 75-250mm f/3.8-4.5 telephoto zoom launched with the Adaptall-2 system in 1979 as model 04A, and was revised in 1981 as model 104A with an updated barrel, remaining available until 1984. It extended Tamron's telephoto zoom range beyond the shorter 80-210mm options of the same period.
Both versions share the same focal range and variable aperture, built around a push-pull zoom action typical of Tamron's late-1970s and early-1980s telephotos. As with other Adaptall-2 lenses, the same barrel accepts adapters for Canon FD, Nikon F, Minolta MD, Olympus OM, Pentax K, Konica AR, Contax/Yashica and M42 mounts.
The longer reach compared with Tamron's 80-210mm zooms suited wildlife and sport shooters working with modest budgets, though the moderate maximum aperture and simpler optical formula of this era mean it gives up contrast and speed against Tamron's later SP telephotos.
Buyers will find both the 04A and 104A on the used market, and it is worth noting which revision a listing describes since barrel details and included adapters can differ. Check the push-pull zoom action for looseness, confirm any tripod mount is intact, and examine glass for haze typical of this period.