You asked

Ttartisan 11mm f 2 8 fisheye vs laowa 11mm f 4 5 ff rl?

Both are 11mm manual-focus primes for full frame, and neither is stabilised, so the choice mostly comes down to aperture and mount.

The TTArtisan 11mm f/2.8 Fisheye is my pick if you shoot in dim light or want more background separation. It opens wider than the Laowa, and it also fits Canon EF and Nikon F bodies, so it works on older DSLRs as well as mirrorless. It's the fisheye of the two, too.

The Laowa 11mm f/4.5 FF RL is a slower lens that covers the mirrorless mounts: Sony E, Nikon Z, Canon RF, L-Mount and Leica M. If you're shooting in good light and want to stay on one of those systems, it's a fine choice.

For the aperture basics, see Lenses.

Written by Claude from this site's pages.

From these pages