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Optical Considerations

When setting up the green screen shoot, be sure to follow these simple rules to make your Ultimatte compositing in post an enjoyable experience. Failure to use these guidelines will result in extra weeks of hand masking, painting and compositing your footage. Which is cheaper then getting the stage, crew and cast together for another shoot. 

Dont's

  1. Use fog or diffusion filters 
    • They diffuse the light from the backing onto the foreground subject, making it harder for Ultimatte to seperate the two. 
    • Results in a serious amount of blue / green spill on the foreground subject. 
  2. Boost the gain on the camera 
    • Boosting the gain increases the noise in an image. 
    • The noise is amplified by the Ultimatte process, creating a less then perfect composite. 
  3. Use Automatic gain control or automatic iris 
    • They cause fluctuations in the backing brightness during recording. 
    • The backing needs to be consistent in color temperature and brightness. 
    • Real camerapersons don't use auto-anything, stop being a wimp and learn how to shoot. 
Do's
  1. Use polarizing filters 
    • They eliminate glare from glass in your foreground footage, allowing for clean "see through" glass composites. 
    • Be sure to compensate for the 2 - 2.5 stop drop in light levels entering the lens. 
  2. Keep the aperture around F4 or F5.6 
    • This eliminates the vignette effect most lens have when wide open. 
    • Be sure to compensate for the increase in depth of field, by moving the camera back. 
  3. Keep a tack sharp focus on your subject 
    • Ultimatte works best if the backing is out of focus. 
    • Reduce that depth of field 
  4. Use manual focus/iris/aperture. 
    • All factors in determining the shot should be set up and then locked in for the camera roll. 
    • In between shots, parameters can be changed. 
     
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