The optional normal may be used to assign a normal pattern to the camera. For example:
camera{
location Here
look_at There
normal{bumps 0.5}
}
All camera rays will be perturbed using this pattern. The image will be distorted as though you were looking through bumpy glass or seeing a reflection off of a bumpy surface. This lets you create special effects. See the animated scene camera2.pov for an example. See "Normal" for information on normal patterns.