What exactly is the difference in cameras regarding FOV and image transformations?
Make Perspective Camera (vuo.scene.make.camera.perspective) and Make Fisheye Camera
(vuo.scene.make.camera.fisheye) have a FOV setting. If you use Make Perspective Camera and set the FOV to 180 degrees, is that the same as fisheye?
In physical lenses, such as fisheye, ultra wide, wide, telephoto typically define a range of focal lengths & FOV.
So a fisheye might range from 4mm to 12mm focal length. Natural human vision lenses are in the 55mm range, wide & ultra wide fit in-between normal & fisheye (18mm-40mm).
There is also image transformation mapping based on the lens design: Stereographic (not to be confused with Stereo 3D), Equidistant, Equisolid, and Orthographic. For natural to the eye FOV, these mappings converge, but with true fisheye lenses, it makes a difference which to use depending on the application.
Also in real fisheyes, FOVs are now approaching 240-270 degrees. Inexpensive Laowa fisheyes I think are in the 220 degrees.
If you use Make Perspective Camera and set the FOV to 180 degrees, is that the same as fisheye?
No; the geometric projections are different — Vuo’s perspective camera uses a rectangular frustum, and Vuo’s fisheye camera uses a spherical sector. (A rectangular frustum can’t actually go quite all the way to 180° since it becomes degenerate.)
Is the fisheye camera Stereographic, Equidistant, Equisolid, and Orthographic?
Based on the descriptions on Classification of fisheye lenses and the attached composition, where the lines are the same distance apart on the periphery as they are in the center, we believe it’s equidistant.