[Rover]

... but a popular focal length, it seems. After Laowa, the "7Artisans" brand apparently wanted to take the slice of the super-mega-hyper-ultra-wide lens pie. 

https://www.mirrorlessrumors.com/just-announced-new-7artisans-9mm-f-5-6-ff-lens/

It'd be interesting to see one of those (or the other SMHUW lenses from - say - Laowa) in this theatre, someday. Just to know what we might be getting ourselves into.  (but I know that if I ever get a chance to try one of these out, I will).

[toni-a]

Not tempted to get one.... it's just for those after numbers.... However in photography there are trends and the actual trend seems to be the ultrawides, i am more on the traditional side

[Rover]

It is here.
https://www.sonyalpharumors.com/just-announced-new-7artisans-9mm-f-5-6-non-fisheye-full-frame-e-mount-lens/
Isn't that the 4th 9mm f/5.6 lens on the market, and all from the Chinese manufacturers?

[wim]

There is a 10 mm F/3.5 Samyang XP Premium lens in my collection, and so far, from F/5.6 it is not only excellent, but did beat anything else in that UWA-bracket, including the Voightlander 10 mm F/5.6. It is big, and I use it with an adapter for my EOS-R, but I really dig it.

Wasn't cheap, and I do not know whether it still is in production, but I find it very useful for indoor shooting and landscapes. It has become one of my top 3 prime lenses since I got it about 4 or 5 years ago.

What is really awesome is that from F/5.6, the light fall-off is well under control, and corner sharpness is actually quite good, compared to anything else I have tried, and that includes the Canon 11-24L. 

It's auto-aperture, and manual focus, but with the focusing options on the R it is just fine, although not a lot of focusing is required, really.

[Rover]

Let's see who makes the first 8mm rectilinear lens. I guess the race is already on.