// normal perturbed camera
camera{ location < 1.70,  2.50, -4.50>
        angle    75
        right    x*image_width/image_height
        look_at  < -1.00, 2.50,  0.00> 
               normal{ crackle 0.25 turbulence 0 
                       scale 0.25 translate<0.3,0,0>}
     } // -------------------------------------------