Carl Zeiss Makro-Planar T* 50mm f/2 (ZE, ZF.2, ZK) - Sample Images
Info and Reviews:
Optical design: 8 elements in 6 groups
ZE (Canon EOS)
ZF and ZF.2 (Nikon F). ZF lens has no electronic coupling and ZF.2 do, this gives it better support for newer Nikon SLRs.
ZK (Pentax K)
Covers: Full-frame (24×36mm)
More info / Review: