In this video I test my new Zenitar 16mm f2.8 lens. I also make a quick shootout against a Kern-Paillard and two $10 C-Mounts.
Its a “Fish Eye” but as you can see its not to “fishy” on s16.
Its an M42 Mount and does cover full frame and can be mounted on a 5D, A7, t3i, GH4, NX1 etc etc.