During a prep on Friday, I had a Red Scarlet, 24mm Ultra Prime, Red Rock receiver w/ motor, Parallinx transmitter and Red Brick (yes, about 2.5lbs!) on my MoVI M10. The total weight was above 12lbs. I was able to balance it without any problems but once I started setting the motor strength, I couldn't get the pan value higher than 75 without oscillation. I tried turning the MoVI off and on again, resetting the android (Nexus 7) tablet and still found the pan would vibrate any value higher than 75. The roll and tilt were relatively low also. The MoVI battery was fully charged. About a week prior to this prep, I had a Red Epic with a total weight in the neighborhood of 10.5lbs. I had the stiffness values as follows: Pan: 175 Roll: 100 Tilt: 70 With the relatively low stiffness values with the Scarlet on it, I played around with the MoVI by walking around with it, doing some whip pans and extremely high and low tilts. It seemed to handle the weight fine. However, I walked away to speak with someone at the rental house and returned to find the director playing the MoVI and it had gone limp. I don't know how he made it go limp. I checked the battery to find all the cells were still around 4.0 volts per cell. Should I attribute the low stiffness settings for such a heavy set-up to the higher weight or is there something else happening? My thinking so far has been the higher the weight on a MoVI, the higher I'd be able to get the stiffness values before experiencing oscillation. -Kurt
It has to be because of the balance (unless he touched the head during operation). There are many situations where a rig is balanced at 'neutral' and horrendously out of balance at different rotations. I always check that the rig will hold at various roll settings - the more 'dutch' the better the balance - Tabb mentions this is indicative of a good balance at the end of his balance tutorial. I tend to prioritise the pan balance over other things like perfect stasis at all tilt angles. It sounds patronizing, I know, but I find that a good balance is elusive and requires a lot of testing. Same thing with the stiffness settings. You may be aware that the stiffness settings affect each other dynamically. If you can't get the same settings it's because you have a different distribution of mass on the rig and/or the balance is off/different. Sorry I couldn't be more helpful but I would point out that I haven't had any trouble with rigs at the target weight in all tilt/pan ranges in all sorts of orientations, because I am obsessive about balance.
Hey Brett, Thanks for your response. I don't know if I fully understand what you mean when you say "There are many situations where a rig is balanced at 'neutral' and horrendously out of balance at different rotations." At 'neutral is the only way I know how to balance the rig. all the axis were balanced. I checked the charts and the motors stress' (at neutral) were all very low (pan was like at 4%). I did roll the MoVI about 45 degrees after it was balanced and set-up and didn't feel any oscillation. I'm not really concerned about why the MoVI went limp, I'm more concerned why I couldn't get the pan stiffness numbers higher than 75.
I mean when the pan tilt and roll are all at 0. Did you do the roll test? Do the roll test at various roll test at various tilt settings to know you've got a good balance. Stiffness is related to the distribution of mass around the COG as well as how well you've balanced it. Did you put the accessories in different places, or use a very different lens (in terms of weight and COG (length))? The stiffness settings should be judged by the image, not by the numbers, IMO. If it looks good it is good.
Kurt based on your description and weight it is likely the battery did not have the juice at 12v. Change battery to a fresh charge since you indicate it worked ok with initial setup. For the setting you should get higher than 75 but the lower setting may be due to weight. Shoot an email to support.
Lower stiffness settings could be attributed to a loose connection somewhere. Check that all clamps are tight and secure, the aluminum roll beam is tight to the roll motor, the roll beam adjustment is tight, etc. If anything is loose the oscillation will occur at a lower stiffness. I would expect your settings to be closer to your earlier setup. As for the limp action, low battery and/or out of balance is usually the issue. Also could've been mishandled, like manually trying to move pan or roll or another force acting on the stabilized portion of the rig which is basically causing an artificial out of balance situation.
Thanks Brett, Gary and Brad! Brad, I think you found the solution to my low stiffness settings for the pan motor. The MoVI was really torqued on its last job. To use the Easy Rig, we removed the top handle and relocated it so it look like we rotated it 180 degrees (the top handle faced the operator after the relocation) While the operator really liked the set up, it torqued the MoVI where the handles attach and where the pan motor attaches. I probably over-torqued the screws trying to get it to stop rotating. The limpness was most likely a combination of weight and mis-handling. It never went limp while I was handling the MoVI. I'll double check the connections and tighten up the rig. Thanks again everyone, I really appreciate your input!