Minolta released the AF 100-200mm f/4.5 in 1986, early in the Maxxum (Dynax) autofocus system launched in 1985. Its constant f/4.5 aperture set it apart from the variable-aperture zooms that dominated Minolta's affordable telephoto range, and it was discontinued as designs like the 100-300mm f/4.5-5.6 took over that niche.
It uses 8 elements in 7 groups with a 7-blade diaphragm closing to f/22, and takes 49mm front filters. Angle of view runs about 24.4 to 12.3 degrees, minimum focus is 1.9m with roughly 1:8.3 maximum magnification, and the lens weighs approximately 375g.
Holding f/4.5 throughout the zoom keeps exposure and viewfinder brightness consistent while framing, unlike variable-aperture rivals that dim toward the long end. The barrel does not extend during focusing, easing use with hoods, and it renders a smoother background than most consumer zooms of its era at 200mm.
It was pitched as a lighter, cheaper alternative to constant-aperture 80-200mm f/2.8 lenses and now sells for modest sums secondhand, often paired with Maxxum/Dynax bodies. It also fits Sony Alpha DSLR/SLT cameras via the shared A-mount. Check the zoom action and aperture blades for oil residue before buying.