### 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
     }