The Zeiss ZM 85mm f/4 Tele-Tessar is a petite M-mount lens suitable for the Leica M Typ 240 or other M cameras. First class build quality, a nice little gem.
With an adapter, the 85/4 Tele-Tessar makes a very compact optic for mirrorless cameras also (e.g. Sony A7/A7R). Its digital-friendly ray angle of 15.5° makes it well suited for mirrorless cameras. See the ray angle discussion in Guide to Leica.
There is also the made-in-Germany high performance Zeiss ZM 85mm f/2 Sonnar, which was discontinued in 2011 and has even higher MTF than the Leica 90/2 APO. Perhaps Zeiss will resurrect it, as both are ideally suited for mirrorless cameras in resolving power and focusing ability.
Zeiss has sent me a ZM 85mm f/2 Sonnar for testing alongside the ZM 85mm f/4 Tele-Tessar, so I’ll be comparing the two.
A perfect fit: