You asked
Laowa 15mm f 5 cookie ff vs voigtl nder super wide heliar 15mm f 4 5 aspherical iii?
Both are manual-focus 15mm lenses for full frame, so the choice comes down to size, light and mount.
The Laowa 15mm f/5 Cookie FF is a pancake, so it's the one to pick if you want a small ultra-wide to carry everywhere. It also covers the most mounts, including Canon RF and L-Mount, and it works on a Canon EOS R6 Mark II.
The Voigtländer Super Wide-Heliar 15mm f/4.5 opens a little wider, which helps in dim interiors and gives a touch more separation. It's the one for a Leica M11 or a Sony a7 III.
If you shoot Canon or L-Mount, the Laowa is your only option here. Otherwise, I'd take the Laowa for portability and the Voigtländer for the extra light.
Written by Claude from this site's pages.