Focal length 3D
The focal length of the view, i.e. the displayed viewing angle in the 3D view, can be changed in the context menu. From 10° (telephoto or quasi parallel projection) to 90° (wide angle or almost fisheye):
(Image 1: 3D view with 20°)
The upper image with 20° focal length is almost without perspective distortion and corresponds approximately to a parallel projection. The following image with 90° is strongly spherically distorted:
(Image 2: 3D view with 90°)
The default angle is 50° and gives a pretty realistic 3D representation.
(Image 3: Dialog for focal length)
In the 3D view, you can now also set the background color in addition to the focal length with a mouse click M2 in the context menu.