Dead Link Removed. Short of it: it's good but not as good as later telephoto lenses with apochromatic glass.
Possibly true. BUT!
Although I like and respect the well meaning folk who contribute a great service at Rokkor Files, one has to take with a large dollop of salt anyone whose conclusions which are based on tests run with a color negative film with the lightest plastic camera body available mounted on a tripod so light they admit that they had to add a weighted bag to even get useful results.
What happened to the addage,"The lighter the camera the heavier the tripod"? That lens could weigh twice what the 570 weighs. Minolta made the XK, XKmotor, XD-5, XD-11 for such serious persuits. The 570 is an intentional compromise intended to do most things for most people, whose needs are weekend occasional snapshots. Light tripods do little more than prevent small cameras from crashing to the ground, and delude the person who purchased them into accepting the hype they are sold by.
What does "good" mean? It is at best misleading to test on the least capable type of material available and then scan on a system which by default injects adjustments of its own. (Nearly all scanners do this with Color neg. film, they have to or they would drive the user nuts) I own a Minolta 5400II, which was the most obviously one used and at best any (color neg.) output from it (or most others) must be considered subjective and derivative. Objective is not possible as it comes equipped.
Lens quality is itself subjective and cannot be expressed in numbers and measurements. Lens quality must be determined using materials which do not inject qualities of their own. Color neg. does not fit this criteria. B&W and some chrome films do. You need to make photographs in real light of real subjects and even then "good' is relative to the image that was intended to be there.
Marketing hype does not a great lens (or camera, or tripod) make.
Fred
