You asked
Is the voigtl nder color skopar 28mm f 2 8 aspherical worth it?
Yes, if you want a small, manual-focus 28mm for full-frame Leica M bodies, this is a sensible buy. It's a prime, so you learn to see the frame before you raise the camera, which is a big part of why fixed focal lengths work so well for street. 28mm is wide and immersive, though, so expect to get close to people.
It's manual focus only and not stabilised, so it suits photographers who are happy to focus by hand. It fits a long list of Leica M bodies, from the Leica M10 to the Leica M11. If you're not sure full frame is worth the cost and size, the sensor guide makes the case for APS-C, and the street page explains why 28mm is a real choice for street work.
This site doesn't list prices, so compare the cost against what you'd spend on the alternatives before you decide.
Written by Claude from this site's pages.