While balancing and using the movi with the cooke panchros (100m). I noticed that when I shift the focus of the lens. This causes the balance of the camera shift quite alot, and it forces the rig to tune the motors at lower numbers. Is there any tips to deal with this issue? Or it's recommended to use as light a lens as possible to avoid CG shifts. Aperture shifting does not seem to affect the balance for obvious reasons. I am using RT motion remotes Payload 6.2 KG
Interesting. While I've shot Cookes on the MoVI, I've never shot at that length with them. I have used the ultra primes through 100mm and never had a problem with those. Your best bet would be to balance for your average focal length if your pulls are minor. Experiment to find the limits of performance.
The way to test this , is to balance the rig. And then shift the focus while the rig is off. u will notice that the rig tilt balance will shift. If you have the Movi on, the gyros and motors will take over, however if this means the motors have to work very hard.
This is caused by the elementals in the lens moving, I guess . LOL do we need a counter balance motor for this?
Charles I would suggest tuning for the mid point of the movement or if you have time determine the actual focus range for the shot and then tune for the midpoint of that range.