Jim proves that perpetually changing camera gear is futile & counterproductive.
here's a comparison
Since all my Pentax lenses would shoot wide open, here's a tripod shot using the Vivitar 28-105 at 105mm f/5.6 to compare with the 45-200. That shot was taken an hour earlier and at 97mm (gosh what precision!), so apples are compared but like Granny Smith to Gravenstein. As noted in other posts, the Vivitar/Kobori 28-105 continues to show itself as a very nice lens!