1) Tracking: The tracking knobs must be adjusted when working in the FRAME ADVANCE mode on the VCR to eliminate the noise and interference which causes much of the image to be obscured. A four-head VCR is highly recommended.
2) Timing: There will be an extra frame between the time the ball is dropped and the time it is observed to move. This is because the first frame constitutes a movement of half a centimeter. Other subsequent frames constitute more significant displacements within the realm of many centimeters which can be seen on the screen if you look carefully for the first few. A dropping device is currently under development to minimize the uncertainty in identifiying the first fram of motion.