200/4 Super Takumar.
Tele-Tessar - no cemented elements.
Performance - as in Canon 70-200/4L lens.
Virtually no resolution drop across the frame. :)
Build as a tank.
Auto/Manual switch.
I've sold it - sounds like quite stupid decision, but on APS-c sized sensor my Jupiter-21M was just all-right comparing to Tak, and it was shorter (more my bag compatible). Additionally, I've bought three new lenses to play with :)
I highly recommend this lens.