Advanced Lens Centering and Distortion Tutorial

The optic axis of a lens determines the "point at infinity" towards which objects converge as they move further away, and about which radial lens distortion occurs. Knowing its location is crucial to being able to avoid systematic errors in inserting CGI effects and removing distortion accurately.

Imaging software such as SynthEyes, 3dsmax, Maya, Lightwave, Cinema 4D, etc all make a conventional assumption and approximation that the optic axis of the lens occurs exactly at the center of the image. However, this is rarely the case as camcorders are subject to sensor chip placement errors, and film cameras are subject to off-centered film scans.

This advanced tutorial shows a way to determine the center location and correct it.

Notes:

  1. Tutorial is 14:55 and 20 MB. You can download the mp4 by right-clicking this link: Centering.mp4
  2. You can download the 50x27 inch lens grid and print it at most copy shops such as FedEx Kinkos.
  3. All tutorials and images (c)2009 Andersson Technologies LLC, not for re-distribution or usage other than with SynthEyes.
  4. Everything is done and shown real-time on an 8-core (16-thread) 2009 Mac Pro running 64-bit Windows Vista. The process is the same in OSX.