I've been conducting many lens tests on my ist-D....which is now easier with digital! One clear conclusion is that the Pentax 20-35/4 lens is perfect for the ist-D. I cannot find a lens in it's range (zoom or prime) which beats it.....period. I think getting the cheaper FAJ or the new ist-D only DA lens just does not make sense for many Pentax shooters. Pair the Pentax 20-35 with a really wide lens that also works in 35mm.....such as the Sigma 12-24 (which I have not yet tested).
Regarding the Pentax 100/2.8 FA Macro....it's a pretty good lens. But much to my surprise, my Tamron 90/2.8 Macro just beats it across the board....at all f-stops. All published lens tests suggested this outcome....and they are right this time. The Pentax 50/2.8 Macro is absolutely superb optically, and works great on the ist-D. So does the Pentax 80-200/2.8 FA...very sharp. I'm not quite as impressed with the FA 28-70/2.8. Robert James
