Downtown Toronto at night -- NEX-5 & Zeiss 50mm f1.4 Rollei QBM Mount. Click for larger.
I have had this Carl Zeiss HFT (German version) for a number of years. Originally used with the Canon adapter, but could not focus to infinity, even after I shaved the rear lens guard to the minimum, the butt still hits the mirror. Just got my Rollei-NEX mount and it works a charm on the NEX-5. This is such a beautifully made lens! All metal and the focusing is nicely damped and smooth. All markings on the lens are engraved. Optically, it's near perfection as a 50mm lens. All apertures are usable.
Unfortunately, there seems to be variations on infinity focus with some lenses. My Rollei QBM mount Distagon 35mm f2.8 is just slightly shy of attaining infinity focus. It's a shame, as the Distagon is also a very nice lens. Looks like it's optically similar to the Contax version.