    The 'direction' vector serves two purposes.  It tells POV-Ray the initial
 direction to point the camera before moving it with look_at or rotate vec-
 tors.  It also controls the field of view.

    NOTE: This is only the initial direction.  Normally, you will use the
 look_at keyword, not the direction vector to point the camera in its actual
 direction.

    The length of the direction vector tells POV-Ray to use a telephoto or
 wide-angle view.  It is the distance from the camera location to the imagi-
 nary 'view window' that you are looking through.  A short direction vector
 gives a wide angle view while a long direction gives a narrow, telephoto
 view.  This figure illustrates the effect:

                      |\                                      |\
                      | \                                     | \
                      |  \                                    |  \
                      |   \                                   |   \
       Location       |   |         Location                  |   |
         *------------> |             *-----------------------> |
             Direction|   |                                   |   |
                      |   |                                   |   |
                      |   |                                   |   |
                       \  |                                    \  |
                        \ |                                     \ |
                         \|                                      \|

    Short direction gives wide view; long direction narrows view.  The de-
 fault value is 'direction <0,0,1>'.

    Be careful with short direction vector lengths like 1.0 and less.  You
 may experience distortion on the edges of your images.  Objects will appear
 to be shaped strangely.  If this happens, move the location back and make
 the direction vector longer.
