I picked up this lens for $75 and tested it on my Sony A200 lens has a F4-5.6 circa 1993 vintage and it stacks up supposedly to
the other lens in that category..here are some test picks at maximum 300mm focal length (aka 450mm) all hand held shots
The reports on the web are true it is quite fast and does not hunt like many other super-zooms it has pretty good sharpness at the wide end and really clear at the intermediate and just good at 250 and a little soft at the 300mm which can be fixed up in PP the colors are not the Minolta colors. I think I will use it for the winter and for those really good composures pull out my old classic Minolta Big Beercan 75-300mm F4.5-5.6 which is a sharpie thru-out and has more vibrant colors.
For those on a low budget this Sigma can be had in Canon, Nikon mounts and can get the job done.