If eventually you are thinking of the 900, well then that is different.
I'm sure my next camera will be full frame, just have to wait and see whether that'll be the A900 or, what I'm actually hoping for, an Alpha 800 (lower resolution, better high ISO performance, perhaps a higher framerate). So on such a camera, the Zeiss would be a perfect general use lens.
I'm not really worried about the equivalent range of the lens. I'll keep the Zeiss 16-80mm for wide-angle shots, at least, as long as I'm still shooting with an APS-C camera (with a FF, I'll sell it). Since I find myself using the 16mm end quite often, I'd be stupid to sell the lens. However, it does make sense to me to replace the CZ16-80mm for the longer end, because of the superior quality of the CZ24-70mm.
The Minolta 50mm f/1.7 was also suggested to me on a Dutch forum, but I don't really like buying second-hand lenses. You never know whether anything's wrong with it, there might just be a tiny little scratch on the surface of the lens...
So far I am getting away with one set of 77mm filters (well only a polarizer for now really). The up coming 16-35 CZ and the existing 135mmf1.8 are also 77mm, hmmmm!
. I'm very interested in both the Zeiss 85mm f/1.4 and 135mm f/1.8, the first most of all. I hope Sony will announce a more extreme wide-angle zoom some time in the near future, I'd prefer something like a 14-24mm instead of the 16-35mm...
- Bjorn -