// 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{ bumps 0.1
                scale 0.15  translate<-0.1, 0.15,0>}
      } // -----------------------------------------