Loud gear mesh noise using Bartech Follow Focus and Red Primes

[Allee Chance]

I'm using the Bartech FF for the first time with Red primes and I'm encountering two issues.


There is too much gear noise.Not so much a problem on a slow turn but on a rack focus it is too loud. It requires considerable effort to turn the focus barrel. Perhaps this causes extra pressure on the gears raising the noise level. Any suggestions? Can the lenses be changed to turn more easily?
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Second, and possibly related to the effort turning the barrel,and when the motor resets to mid-range after set up the gears are stripping because the motor is turning faster than the barrel can keep up. Eventually the motor gear moves away from the barrel and the motor spins and thereby losing calibration with the barrel. I have tried different gears and I have the optimal one on. Jim Bartell suggested stabilizing the rods with perhaps a cable tie so they don't bend away from the barrel. Any suggestions?

Thanks!

Allee




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[Louis Maddalena]

Making sure you don't have any rod flex is definitely a good idea. Also make sure that you don't have any movement of the motor on the rod.

Also, Is this the case with all your Red primes? I'm thinking maybe something is wrong with your lens causing it to be tight. I did not experience any issues like the one you describe with red lenses on a set I was on a few months ago where we were using wireless focus systems.

 

[Nick Gardner]

You have an issue with your lens. It should not be difficult to turn by hand. If the motor is driving it's self off of the lens, it is too stiff. What motor are you using? Be careful, the M-one is really powerful and can damage stuff. The m-one is a little on the loud side, but in literally hundreds and hundreds of shoot days, It has never been a problem on set. Heden motors are quieter, so I useually keep one on hand just in case, but I never had to use it because of sound.

Nick

 

[John Marchant]

Make sure you're mounting the motor the right way round - its possible with most to have a good and a bad orientation with respect to it pushing away from the lens and slipping. That said, your lens sounds like its overly stiff...

 

[Dave Weber]

Also could be that your Motor is pressing to tightly agains the lens gear.

 

[Christopher Lowden]

For what it is worth, I had a similar problem with a Heden motor slipping off the lens. I changed the redrock base torque settings but it did not sole the slipping. Then I realised that not rods are made equally. I was using some expensive 15mm rods that were sleek and shiny but the motor was slipping. I bought some cheap, rough pure alloy 15 mm rods that have much better grip and the motor jumping issue was solved.

 

[paulcurtis]

Also use two rods and stick a clamp at the front so that the rod with the motor has the additional stability of the other rod (if that makes sense), that can help with flex.

cheers
Paul