Gianfranco, the DA 16-45 is a fine lens. I have tested it formally against the excellent FA 20-35. It is definitely in that class, and perhaps just a bit sharper than the 20-35. I have used the FA 24-90 but have not formally tested it. My impression is that the DA 16-45 is in the same class as the sharpest zooms I own -- the FA 20-35, the Tokina AT-X Pro 28-80 f2.8, and the Sigma EX 70-200 f2.8.
One amazing thing about the lens is that it is quite good wide open. Pentax's own MTF evaluation is that the lens is actually best at f4.0 from 16 to 28 mm., and at f4.5 from 28 to 45 mm. That's extraordinary performance. It's also, of course, quite fine stopped down. I have shot it at f16 with very nice results. It goes well on the *ist D. There are occastional CA problems, but you will probably see these on many lenses. I have noticed it on only two shots out of several hundred. There is software to correct CA problems, and I would guess that more software (perhaps PS plug-ins) to correct this problem will be forthcoming. For *ist D zoom users, I cannot recommend this lens highly enough. It is one of the best zooms Pentax has made. The images it gives me are stunning. One is in this month's PUG (keep in mind that it is a reduced jpeg). For some reason Pentax is producing few of them, so if you want one grab the one you saw. They are hard to find. The price looked good, comparable to discount price here. Joe
