[Klaus]

https://www.nisi-lens.com/nisi-9mm-f28

APS-C in case you wonder

[toni-a]

Looks really tempting, at 9mm APS-C you can focus effortlessly except wide open f2.8, at f5.6 with focus set to hyperfocal (0.8 meters) everything from 40cm to infinity is in focus.
Only important thing is to have focus distance and especially infinity focus adequately written on the lens barrel this has been an issue with some samyang models

[giulio]

mtf looks strange to me... almost better and less astigmatic @ f2.8 rather than f8? anyway let's see. 10 blades also a bit strange... why not odd?

@toni-a i doubt it will be so easy to focus perfectly, i tried with a 10mm f4.5 zoom and it wasn't easy at all to archive perfect focus, especially at night when peaking was a noise-only thing...

[toni-a]

mtf looks strange to me... almost better and less astigmatic @ f2.8 rather than f8? anyway let's see. 10 blades also a bit strange... why not odd?

@toni-a i doubt it will be so easy to focus perfectly, i tried with a 10mm f4.5 zoom and it wasn't easy at all to archive perfect focus, especially at night when peaking was a noise-only thing...

Exactly, that's why I would recommend you forget about focusing using viewfinder  in such cases and rely for manual focus on the focus distance on the lens barrel, stepping down is your best ally, at 10mm f4.5 on full frame everything from 40 cm to infinity is in focus if you focus at 75cm distance (hyperfocal distance)