You asked
Best portrait lens for l mount?
The site doesn't yet confirm which portrait lenses fit L-Mount, so I can't name a definite pick for it. The L-Mount page covers the alliance (Leica, Panasonic and Sigma) and notes that Sigma's MC-21 adapts Canon EF autofocus lenses.
For the lens itself, I'd start with a 85mm f/1.8 on full frame. It's the classic portrait focal length, with flattering perspective and soft backgrounds. The Meike 85mm f/1.8 SE Mark II is a budget autofocus option, and the Voigtländer Portrait Heliar 75mm f/1.8 is a close alternative. Check each lens's mount before you buy.
For the full reasoning on focal lengths and light, see the portraits guide.
Written by Claude from this site's pages.