You asked
Is the zeiss c sonnar t 50mm f 1 5 zm good for portraits?
Yes, with a caveat. The Zeiss C Sonnar T* 50mm f/1.5 ZM is a full-frame prime, so on a Leica M body it gives the natural, slightly tight view that my portraits guide describes for 50mm. The f/1.5 opening helps with soft backgrounds and dim light.
The catch is that it's manual focus only. That's a real handicap for moving subjects, so it suits posed or slower portraits best. If you want a lens built for portraits, I'd still reach for an 85mm first.
It fits many Leica M bodies, including the Leica M11 and Leica M10. The lens matters more than the body for portraits, so pick the body on other grounds. If you're building a kit from scratch, start with the lenses guide.
Written by Claude from this site's pages.