Tamron 100-300mm f/5-6.3 — budget autofocus telephoto zoom (86D), multi-mount film SLR fit
Tamron's 100-300mm f/5-6.3 is an autofocus telephoto zoom from the company's affordable D-series, introduced as model 86D in 1998 and followed by an updated 186D in 2001. It gave film-era SLR owners a budget-friendly step into longer telephoto reach.
The lens has a modest variable maximum aperture that narrows from f/5 to f/6.3 across its range, a common trade-off for compact, affordable telephoto zooms of the period. Tamron produced dedicated versions for Canon EF, Nikon F, Pentax K and Minolta A mounts rather than an interchangeable Adaptall system.
Its light weight and simple zoom action make it an easy lens to carry for casual telephoto use such as air shows or school sport, though the slow aperture limits its usefulness in dim conditions and the simple optical formula falls short of Tamron's SP telephotos.
Plentiful and inexpensive secondhand, often bundled with entry-level film SLR bodies. Check autofocus operation and aperture-contact function against the intended mount, examine the zoom barrel for play, and inspect the rear element for scratches common on lenses kept in general camera bags.