So, researchers in Berkeley are applying cutting-edge technology to find out. They are driving to discover what happens when 3D goes bad.
"Headaches and discomfort that's caused by the aberrations in the image that your eyes and brain don't expect are now gone when the 3D is produced correctly," explains Howard Postley with 3Ality Digital.
Yes, but when it's not "produced correctly"?
"I know what to look for and, once you see the problems, they drive you nuts," says UC Berkeley Visual Science Professor Martin Banks.
Banks' lab at UC Berkeley is breaking new ground in the way we perceive depth. Surprisingly little is known about the physiology of stereoscopic vision. Enabling test subjects to see two screens at once using mirrors, his team has established some of the things that lead to bad 3D.
For example, much of what is marketed as "3D" today is really 2D with artificial depth added by computer. When done too quickly, as in Clash of the Titans, it can give you a headache.
Close-ups can unsettle the brain. Often, an object that is supposed to be 4 feet from the viewer, is projected onto a screen 40 feet away. An experiment by Emily Cooper's found that audiences do not take viewing distance into account.
There is also the "Shutter Effect." In a stereoscopic 3D broadcast, both cameras snap a picture at the same time, 60 times per second. However, on the screen, those two pictures are shown at different times , first for one eye, then for the other , making a fast-moving object appear to be in the foreground when it isn't.
The Banks lab has found a solution to this. This doesn't mean stereoscopic 3D is bad for you.
"I'm not very concerned about it. I do wish we did more research on it," Banks says.