Basic stereoscopic 3D filming guide for post production consideration
Filming errors that CANNOT be fixed in post
SYNC
Sub-frame Temporal Discrepancies due to lack of gen lock (electronic time) synchronisation between cameras which causes a difference in movement positions on each eye’s frame.
PITCH
Incorrect 3D camera rig pitch angle alignment and zoom lens mismatch causes a foreground to background vertical discrepancy between the eyes.
DEPTH
Incorrect inter-axial distance between the cameras, giving too much or too little depth parallax.
EDGE
Large, out of screen negative parallax edge violations of the arch, the sides and top of the frame.
CLOSE UPS
Close-ups where convergence causes excessive positive parallax may not be viable 3D.
Issues that are difficult to fix, if at all, so should be avoided
LENSES
Mismatched, non prime lenses can have image distortions that do not match in each of the stereo images.
RETINAL RIVALRY
Artefacts in one eye but not the other, i.e. lens flare, dirt, smears & drops on the lens or rig mirror.
PEOPLE SHOT FOR NEGATIVE PARALLAX (NP)
When shot for NP, people’s heads should not break top of frame.
Filming errors that CAN be fixed in post
POSITION
Reasonable vertical, horizontal, size and rotation of camera position differences.
CONVERGENCE
What should be on, in front of, or behind screen plane can be adjusted within parallax limits.
EDGE
Narrow, left/right frame NP edge violations can be fixed with floating windows.
COLOUR
Reasonable colour differences between the eyes.
Written by Ross Copeland
Stereoscopic 3D Online Editor/Colourist
ross.copeland@sky.com
