Chasing down vibrations, and learning to love the non-coplanar sled

[Tom Wills]

I've had a bit of time between Steadicam jobs lately, doing a lot of conventional operating and handheld, which has given me some time to do some experimenting with my rig. Namely, I've gone on another never-ending quest to nail down vibrations, after having some very small ones in a music video a while back. A lot of that, it turned out, came from a few loose screws, but some of the vibration came from the monitor mounting. As anyone who's seen my obsession with monitor mounting knows, mounting a monitor solidly, with a tilting yoke that never needs to be re-tightened, without any vibrations seems to be my life's quest. (I've done quite a few modifications to how the Cinetronic yoke pivots already, and as most of you know, I used to make monitor yokes for Marshall monitors) So, I began on a journey.

 

I've found one of the best ways of looking for vibration and lack of solidness in the monitor's mount is to look at the reflection of a light in the surface of the monitor. Then, tap the rig. Start on the batteries, tap the post, tap the monitor rods, tap the monitor housing, tap the camera, and go all around the rig. Try it while it's docked, try it while it's on the gimbal on the balancing stud. If you've got vibration in the monitor, the reflections in the monitor will tend to flutter and blur, and then come back to being clear. It's a real sure-fire way of seeing vibrations too small for you to visually detect them.

 

So, a few rounds of tapping on my rig, and I found that there were indeed some significant vibrations coming from the monitor's mounting. No surprise, considering the number of parts involved, and the rather silly clamping block that I had already had to modify after it bent to the point of being unusable. I started removing parts, replacing parts, and eventually machining some replacement parts to see if I could fix it. At the end of it all, I decided to go as simple as possible, however, and just remove all of the mounting hardware between the rods and the yoke. It turns out that Cinetronic/Film Stuff did a smart thing when machining the rods and the yoke. The rods are the exact same distance, center-to-center, as two of the holes on the yoke's crossbar. All I needed to do was press in a couple of bushings on the crossbar to make the 3/8" holes go down to 1/4", and run to M6 bolts through to the holes in the rods.

 

Suddenly, I have a solid mounting solution with no vibration. But, in the process, I lost my coplanar sled. With the yoke as it was originally set up, it was mounted in a clamp that had it sitting 45 degrees below where it sits now. In this setup, the monitor was low and coplanar. It was incredibly easy to DB. But, with the new mounting, I did end up finding some advantages. I had never tried flying the Cinetronic in a higher position, since the only position the clamping mechanism on the Gen1 provided was swept quite far up. But having the monitor almost flat to the rods, as it is in my current setup, feels like a nice medium point - I find my neck is no longer so bent over to see the screen, especially if I'm boomed far down (as a guy of my height often is). And, though it does take a few spins to balance, DB is still no problem, and with a marked sled, I can take it out of the case and get it into my usual flying setup in seconds. From there, I can make whatever changes to the inertial configuration of the sled, and they're just a few spins away from DB themselves.

 

Overall, it's a nice change. I'd implore anyone with the original Gen1 mounting to try this. Perhaps it's just my setup, and perhaps it's my fussiness about having an absolutely vibration free sled, but it made a difference to me. And the bonuses of better visibility and less neck strain are pretty great too!