Carl Zeiss Distagon T* 28mm f/2 (ZE, ZF.2, ZK) - Sample Images
Info, Review and images of the lens:
Optical design: 10 elements in 8 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)