Zeiss's compact Contax standard prime — the Planar T* 50mm f/1.7, manual-focus glass for the C/Y mount.
The Zeiss Planar T* 50mm f/1.7 was the standard prime for the Contax/Yashica mount, offered from the late 1970s as the more compact and affordable partner to the 50mm f/1.4. It became a common kit lens on many Contax bodies.
This is a manual-focus C/Y-mount lens with a 50mm focal length and a maximum aperture of f/1.7. The Planar double-Gauss design with T* coating was tuned for contrast and colour. Further construction details are omitted where they cannot be confirmed.
At 50mm it serves as a natural everyday lens for portraits, street and general photography, with good sharpness and rendering that many find close to the f/1.4 at working apertures. It is compact and easy to carry.
This is one of the most common and inexpensive Contax Zeiss lenses on the used market, a good starting point. Check for internal haze, fungus and coating wear, confirm smooth focus and clean aperture blades, and inspect the front element. It adapts to mirrorless with a C/Y adapter.