Preventing the spinning top effect...

Tonight I stitched the 5 rear angles of a potential plate rig configuration for the first time and susequently solved one of the nagging problems I've had with all of my driving plates to date.

The Problem

When a car turns a corner, its front wheels follow an arc path, the rear wheels follow a shallower arc as they follow through the curve.  Because a rear facing plate camera will always be mounted on the rear of the plate car, in some cases well behind the rear wheels, the camera is tracking the wrong arc as compared to the foreground camera that would have been mounted on the front of the car.  The effect of this in the composite is that it looks like the car is spinning like a top, the background appears to slip by as the car completes a turn.

The Solution

By having the flexibility of using panoramic plates, we can force the camera to follow the correct arc by animating a new path with keyframed back-panning.  I instinctively do this when operating the Libra head on the camera car, slightily delay the pan to hold the vanishing point of the old street for as long as possible before back panning to catch the line of the new street.  This same thing can be accomplished by keyframing the x-position of the stitched plate.  Three keyframes are needed, first and last correspond to the frames where the plate car is entering and exiting the turn.  The middle keyframe should be just slightly prior to the mid point of the first and last keyframe.  This keyframe value should be set to hold the vanishing point of the old street for as long as practical.