First Test:
Zeiss ZF 25mm f2.8 v Nikon 24mm f2 AIS

Performance Comparison at f4 (Centre Frame)

Nikon 24mm f2 AIS at f4 (Centre)	Zeiss ZF 25mm f2.8 at f4 (Centre)

Considering the ZF is giving away a whole stop, it's impressive how it brings to the table all the traditional Zeiss attributes one stop down from wide open: microcontrast and, to a lesser extent, resolution, are clearly superior to the Nikon f2 at f4, rendering a much more 'believable' 3D image. Detailed tests of its wide open performance corner to corner will be the subject of another test, but there is reason to believe that the ZF's wide aperture performance will be exceptional. Here's a 100% crop from the extreme lower-right corner of an APS sized capture:

Zeiss ZF 25mm f2.8 (Wide Open)

Zeiss ZF 25mm f2.8 at f2.8 (wide open). 100% crop: lower-right corner from Nikon D2X

Spot-on wide aperture performance, this: almost Leica-like! How gracefully this resolution is maintained into the real corners remains to be seen . . .