Is the leica summilux m 21mm f 1 4 asph good in low light?

Yes, on paper it's built for low light. Its f/1.4 maximum aperture lets in far more light than a kit zoom, and the primes or zooms guide makes the same point about fast primes. It's a full frame lens, and the sensor sizes page says full frame is the right call for low light.

Keep in mind that it's manual focus and has no stabilisation, so in dim rooms you'll be relying on the wide aperture and a steady hand. It also frames wider than the rangefinder's lines, so you'll need live view or an EVF to compose accurately.

Any of the newer M bodies on its lens page will take it, including the Leica M11 and the Leica M10. I don't have low-light test results for each body, so check their specs against what you shoot.

Written by Claude from this site's pages.