6.4.5  Camera Identifiers

Camera identifiers may be declared to make scene files more readable and to parameterize scenes so that changing a single declaration changes many values. You may declare several camera identifiers if you wish. This makes it easy to quickly change cameras. An identifier is declared as follows.

CAMERA_DECLARATION:
    #declare IDENTIFIER = CAMERA |
    #local IDENTIFIER = CAMERA

Where IDENTIFIER is the name of the identifier up to 40 characters long and CAMERA is any valid camera statement. See "#declare vs. #local" for information on identifier scope. Here is an example...

 #declare Long_Lens =
  camera {
   location -z*100
   angle 3
  }
 #declare Short_Lens =
  camera {
   location -z*50
   angle 15
  }
 camera {
  Long_Lens  // edit this line to change lenses
  look_at Here
 }