I had a Zeiss-Nettar (515/2) that I got cheap and repaired with help from a lot of people, Donald Qualls among those
The bellows is the hardest part to get in good shpae in those
Gave it away to my father in law.
The lens (novar) was very decent, nice image quality and had that non-coated look that is so cool for portraits. I could only shoot 10 or 12 rolls with it.