I'm trying to find the best set up to shoot 2K/4K fish eye but running into a plethora of information regarding sensor sizes, focal lengths.

Specifically, I'm trying to achieve a full spherical fish eye image on a micro 4/3 sensor. How do I know which lenses provide the full spherical image rather than cropped or fisheye distortion that fills the entire frame.

Any insight or resources would be greatly appreciated, thank you!