Leica M lenses for portraits
For portraits it is less about the spec sheet and more about how a lens draws a face: smooth backgrounds, a gentle falloff, and rendering with a bit of character.
What makes a portraits lens
Short teles are the traditional portrait focal on an M. A 75mm or 90mm gives flattering compression and lifts your subject off the background. But portraits work wide too: a characterful 35 or 50 up close keeps the environment in the frame and tells more of the story. What matters most is the rendering, smooth bokeh, a soft transition from sharp to out of focus, and a look you cannot fake in editing.
Fast glass helps here, both for low light and for the shallow depth that separates a face from its surroundings. f/2 is plenty; f/1.4 and faster gives that creamy, three dimensional look wide open. The tool below is set to portraits, weighting bokeh and rendering over raw sharpness, and it will happily surface a soulful vintage lens next to a modern ASPH.
Questions
What focal length is best for Leica M portraits?
75mm and 90mm give the most flattering compression and subject separation. 50mm is a versatile middle ground, and a characterful 35mm works well for environmental portraits.
Does aperture matter for portrait lenses?
Yes. A wide aperture of f/2 or faster gives the shallow depth of field that separates your subject from the background and produces the smooth bokeh portraits are known for.