Minolta launched the AF Zoom 100-300mm f/4.5-5.6 in 1988 as a budget telephoto zoom for its Maxxum (Dynax) autofocus system. It sat below Minolta's faster glass and was later joined by sharper apochromatic APO and APO D versions plus a motorized xi variant.
It uses 11 elements in 9 groups, a 9-blade diaphragm stopping to f/32, and a 55mm front filter thread. Maximum aperture runs f/4.5 at 100mm to f/5.6 at 300mm, angle of view spans about 24.4 to 8.2 degrees, minimum focus is 1.5m, and it weighs roughly 410g on Minolta's 5-pin AF mount.
Lacking apochromatic glass, it shows more colour fringing at 300mm wide open than the later APO version, and contrast softens toward the long end in backlit scenes. The one-touch push-pull zoom is light and fast to use, and low weight suits a walk-around telephoto, though the mostly plastic barrel feels less solid than Minolta's G-series lenses.
It appears cheaply on the used market, often bundled with Maxxum/Dynax bodies, and still mounts on Sony Alpha DSLR/SLT cameras via the shared A-mount, though it needs a body with a focus motor since it has none built in. Check the push-pull zoom for looseness, the rear pins for corrosion, and the aperture blades for clean snap-back before buying.