This allows real world cameras to be modeled by specifying the coordinates of a 4th degree polynomial that relates a pixels distance (in mm) from the optical center on the sensor to the angle (in radians) of the world ray that is projected onto that pixel. This is available as part of the panoramic lens type, however it can also be used to model lens distortions in projective cameras for example. Differential Revision: https://developer.blender.org/D12691