25-85mm Rokinon, 18.5mm Sigma 20mm with a little added jazz.
Oddly I was routing for them in this effort, but the mixed clarity of stating originally what they were doing via the Roks, then going back to rather strict lipped "these are original designs", then back to publicly stating they were using the Sigma on the wide was an adventure. Not to mention some of the more combative posts with a couple of lens professionals who literally service the optics they were using and could easily A/B and precisely measure (not just in physical dimensions) what they were doing.
The Rokinons are inexpensive enough to tinker with and explore methods of getting more funk out of them and I think there was some real marketing POV to explore there plus putting them into a more robust housing as well.
Either way if was an interesting effort and I did like the form factor.