Center of Gravity (CG) Test Rig
This rig is for finding and adjusting
the camera and counterweights about the center of gravity of pipe or tubing
which should be the center of the tubing/pipe (1). This makes adjusting the
whole assembled system easier. Once the camera or counterweights are balanced
they should remain in any position.
Note: This Arri 16S has slots (2)
and screws for CG adjustments.
Note: The CG (1) is the center of
the pipe and through the center of the camera. Dovetails (3) allow vertical
and horizontal balance adjustment.
These lead weights (4) are cast in 100" film cans with stubs of Speed Rail ©
1-1/4" couplers (5). The CG is in the middle of the horizontal pipe.
This rig can be made with any 4 bearings
or wheels (6). Cheap fixed casters would do. Attach the rig to a secure bench
or base. Don't use a tripod unless it has a center post and can't tip over.
When adjusting a camera consider a safety strap from above to catch the camera
if something goes wrong. Provide stops so the camera can't slide out of the
adjustable slots or dovetails. Make sure the lens can't slide out of the mount
when the camera is looking down. It is easier to adjust the up and down axis
with the camera looking up or down. There is no gravity to fight.
Make sure all adjustments are locked
off after balancing.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.