“Jello Effect” and 3D shooting don’t mix very well as it makes very difficult to synchronize left and right images, especially on 3D rigs where one camera is inverted vertically such as in 3D mirror rigs. The solution: using a neutral density (ND) filter will darken the scene and force longer exposure times which in turn mask most of the “Jello Effect”. Video proof here courtesy of Chad Johnson.
Source: Stereoscopynews.com