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

Performance Comparison at f8-f9.5 (Centre Frame)

Nikon 24mm f2 AIS at f8 (Centre)	Zeiss ZF 25mm f2.8 at f9.5 (Centre)

One or two point to note here: the ZF was tested at f9.5 against the Nikon's f8. Either the f2 rates its apertures rather too optimistically, or perhaps the f2.8 is a little faster than it pretends to be . . . the lens certainly looks big enough to be an f2. Also note the typically cool colour rendition of the Zeiss: though the natural lighting in this series of shots varies somewhat, the Nikon f2 is consistently warmer.

Performance Comparison at f8-f9.5 (APS-sensor 'corner')

Nikon 24mm f2 AIS at f8 (Corner)	Zeiss ZF 25mm f2.8 at f9.5 (Corner)

Typically, both Nikon and Zeiss wide angles like to be stopped down to at least f8 to deliver their best; once again, though, the new ZF outstrips the ancient AIS lens by a significant margin.