I now consider the Zeiss 100mm f/2 Makro-Planar [datasheet] one of the finest lenses I’ve ever used (perhaps the finest, see my July 30 blog entry). I use the 100mm Makro-Planar on my Canon EOS 1D Mark III with a CameraQuest Nikon-to-Canon adapter.
Zeiss states that 100mm Makro-Planar uses the “ARRI/ZEISS Master Prime optics from Hollywood’s movie industry”, though exactly what that means is unclear, since the Master Prime optics are truly exotic and f/1.2, with price tags to match.
The ARRI “Master Prime” lenses are used by cinematographers, where $20K for a lens is pocket change relative to the overall movie budget—but adequate to build world-class, no-holds-barred optics. Interesting reading. To be clear, the 100mm Makro-Planar is not a “master prime” at f/2, but in any case the images it produces are stunning.
You can purchase the Zeiss 100mm f/2 Makro-Planar through amazon.com - Adorama . (Adorama is a reputable and reliable dealer, at least with several orders I’ve placed). The Canon 1D Mark III is my favorite digital SLR yet, and is in stock at amazon.com as well; the combination is wonderful. (I suspect that the Nikon D3 will give the EOS 1D Mark III a very serious run for its money, but that remains to be demonstrated).