You asked
Best wide angle lens for canon rf?
The only Canon RF lens I can confirm from this site is the Laowa 15mm f/4.5 0.5X Wide Angle Macro. It's a full-frame 15mm, so it's properly wide, and it's a macro too, so it'll get close to small subjects. It's manual focus only and has no stabilisation, so it suits deliberate, slower shooting, like landscapes, architecture or close detail.
I can't confirm the mount for the other Laowa 15mm f/4 Wide Angle Macro, so check its listing before you buy. For a full list of lenses that fit Canon RF, see the Canon RF catalogue. If you're comparing apertures, the Lenses guide explains why a wider f-number helps in dim light.
Written by Claude from this site's pages.