Rotating Camera 

Cyclic animation of the camera.

The animated camera - we can animate camera location as well as the look_at point or angle of view!
 
Rotating Camera
Here is a sample:

// the rotating camera: ----------
camera {
  angle    35
  location <3.0 , 1.0 ,-20.0>
  right    x*image_width/image_height
  look_at  <-1.0 , 3.5, 5.0>
  rotate   <0,-360*(clock+0.10),0>
//---------------------- end of camera

scene description for POV-Ray:
"cam_rot1.ini" and
"cam_rot1.pov"

With some ups and downs:

#declare Jump_Start  = 0.5;
#declare Jump_Height = 7;
#if (clock < Jump_Start )
 #declare Camera_Y = 1.00;
#else
 #declare Camera_Y = 1.00
   + Jump_Height*
     0.5*(1-cos(4*pi*(clock-Jump_Start)));
#end

camera {
 angle 38
 location <3,Camera_Y,-20>
 right x*image_width/image_height
 look_at <-3,3,5>
 rotate<0,-360*(clock+0.1),0>
} //------------------- end of camera

For another interesting samples on the animation of camera take a look at the POV-Ray subdirectory "scenes\animation\camera2"