When Pentax made a completely new system, and the diminutive Q family was born, they also made a fisheye, for it. They presented it onJune 2011 and marketed it as “toy lens”, ok, but they made it.
It has a fixed aperture and has manual focus, on a small imprecise near-far focus scale. The Pentax Q system evolved in only 4 iterations with 2 different sensors, with different sizes. So this microscopic and lightweight lens (29 g!!!) has two different FoVs: 173° (Q7/Q-S1); 160° (Q/Q10). It cannot be adapted to anything else, but being completely manual could maybe be modified. There are contacts in the back, but no mechanical couple to camera moving parts.
I’m the proud owner of 2 samples of this lens along with the incredibly precious Pentax Q10 Type 01 Evangelion Edition.
VR PANORAMA purpose
On a Pentax Q10 (sensor diagonal 8,14mm, crop factor 5.3) PTGui gives a real focal length of 3.41mm. with a fisheye factor of -0.5 (equisolid lens) and horizontal fov just a tad less 84°. Needs a 6+1+1 shooting pattern giving as output a 13162×6581 pixel equirectangular image. it’s a tad soft, has chromatic aberrations but it’s not a bad lens. Probably a re-cased cctv lens, but one with more than decent quality.
Unfortunately, Pentax Q system was put on halt, even if still available in eastern countries, and is considered out of production.