Reader BK comments on the B+W XS-Pro filters:
Unfortunately I wasn't thinking about your posting last month when I ordered my Sony/Zeiss 24/1.8 Sonnar for NEX-7 (which is still back-ordered) w/ the XS-Pro filter. The filter indeed does not work with the lens hood. Since Zeiss does not make a 49mm UV filter, I guess I'll return the XS-Pro and get the tried and true B+W 010 MRC.
FYI in case you want to let your other readers know that this is not just a ZE/ZF.2 issue. Any idea whether the 010 MRC actually works w/ this lens/hood?
DIGLLOYD: The B+W 010 MRC or Zeiss filters will both work, because they match the diameter of the lens threads (I verified that a B+W 49mm does indeed work on the Sony 24/1.8 just now). The B+W XS-Pro is a crazy design that extends outwards slightly, resulting in incompatibility with various lenses— a poor investment should your lens collection grow or change.