You asked
Is the voigtl nder septon 40mm f 2 aspherical good for street photography?
I think the Voigtländer Septon 40mm f/2 is a good street lens. On full frame it gives you a 40mm view, a focal length that shows the scene around your subject without much distortion. On APS-C it frames like 60mm, which is more of a reach, so pick the body that suits how you shoot.
Street shooting rewards small and quiet gear, and this lens fits that. The f/2 aperture helps in dim streets, and manual focus suits people who like to pre-set focus and shoot without thinking. The trade-off is that you focus by hand, so you'll need practice.
For a small pairing, the Sony a6400 or Nikon Z fc are both APS-C bodies that fit the Septon. Read the Street guide for how to approach people, and Sensor sizes if you're deciding between full frame and APS-C.
Written by Claude from this site's pages.