[BMPCC + Speedbooster (nikon mt) + Isco 36] widest lens?

[KaBoom]

Hi folks! I have the above-mention equipment and i wonder whats the widest possible lens for this setup. From what i read 28mm should work but 24 will vignette. (prime lens). Is this correct?  Thx 4 help

[Tim McC]

Is your speedbooster the BMPCC version, or one of the others?  This will make a difference...

[Turboguard]

I used the BMPCC speedbooster with the Rokinon CineDS 10mm on this;

Believe it's about 17mm in 35 equal.

 

Then the wide shots here are the same set up;