The Multiplane Downshooter - Frame-by-Frame Stop Motion: The Guide to Non-Traditional Animation Techniques - page 107

Fig 7.15 a diagram of a rudimentary 2” × 4” downshooter stand.
It was inexpensive to build because I used 2” × 4” pine lumber, 5” long × 5 ⁄ 8 ”
diameter carriage bolts, two 30” × 24” plywood quarter sheets, and a piece
of glass. The bolts allow you to take this stand apart, so it can be moved or
adjusted. At the time, I was shooting with a 16 mm Bolex camera, but these
days the camera mount holds a Canon dslr with a zoom lens. There are better
designs for a downshooter stand, and there are adjustments that can be made
to this stand to improve it (like mounting a simple track on the back column
that would hold a camera and allow for tracking zooms), but this simple stand
will suit most of your needs in the downshooting realm. Good luck with your
downshooting. It can be a lot of fun!