#declare maxz=30;
#declare maxy=1.8;

#declare cam_distancez = 4+clock;
#declare cam_distancey = cam_distancez* maxy/maxz;
#declare obj_width = 5;
#declare cam_angle=2*degrees(atan2(obj_width,2*cam_distancez));

camera {
  location  <0.0, cam_distancey, -cam_distancez>
  right     x*image_width/image_height
  angle cam_angle
  look_at   <0.0, 0,  0.0>    
  aperture .3
  blur_samples 500
  focal_point <0,0,0>
  confidence .95  
  variance 1/10000 
}