You asked
Voigtl nder nokton 75mm f 1 5 aspherical vs 7artisans 75mm f 1 4?
Both are manual-focus 75mm primes for full frame, so the choice mostly comes down to mount and that small aperture difference.
The 7Artisans 75mm f/1.4 is the brighter of the two, and it's the one I'd pick if you shoot Sony E, Nikon Z, Canon RF or L-Mount. The Voigtländer Nokton 75mm f/1.5 is the one for Leica M bodies, where it's sold as the Vintage Line version. It also fits Sony E, Nikon Z and Canon RF.
The extra stop of light on the 7Artisans is real but small, and it gives slightly shallower depth of field. Neither has stabilisation or autofocus, so you'll be focusing by hand either way. For portrait work, a 75mm sits close to the classic 85mm, so the portraits guide is a good place to check whether that framing suits you.
Written by Claude from this site's pages.