XYZ Computing has a new article out on the Fanotec Nodal Ninja 3 Spherical Tripod Head

Spherical tripod heads, like the Nodal Ninja, do not resemble spheres. In fact, they usually have more than one straight pieces and look almost like a modern version of the navigation equipment one would find on a 17th century galleon. The "spherical" element is the concept that the tripod head holds the camera in a particular position in space that allows it to rotate about its exact entrance pupil. When this entrance pupil becomes the axis of rotation in every direction, the camera's lens becomes a segment of a sphere. When the photographer uses the spherical tripod head to rotate the camera about its entrance pupil in between exposures, each exposure can become a curved "tile" within a digital spherical representation of the entire environment. The smaller the focal length, the larger this tile will be, so wide-angle lenses require fewer exposures to complete an entire scene.

Fanotec Nodal Ninja 3 Spherical Tripod Head Review