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Footsteps shake / judder - a complete noob

footsteps judder shake

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#1 Emilian Dechev

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Posted 20 January 2014 - 06:04 AM

Hello, everyone!

I am a filmmaker student and I want to learn how to operate a steadicam system. I've got one of the cheapest models with a double arm, but still I think it can offer enough stability for a first time user.
It is the Flycam Vista II kit.
So I started to read manuals and watch tutorials, everything that I can find on the topic. After a while I learned how to balance properly the sled, how to position the vest and adjust the arm and how to hold the sled with both arms.
Now I am facing a major problem with all my shots - there is an awful judder / shake to left and right, in every step that I make. I try to walk carefully, but cannot make it stop shaking.

Is that because my footstep technique is bad?

Is it because the rig is cheap and lacks some function that I don't even know of?
Maybe I am missing some important adjustment?

I hope there is nothing wrong with the rig, and it is all bad footstep technique.

Please watch this video and help if you know how to remove these constant shakes:


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#2 Sanjay Sami

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Posted 20 January 2014 - 09:52 AM

Its strange ... It does not look like vibration from the rig. It looks like the camera panning left and right constantly. Is the camera tight on the plate ? I am not familiar with the rig, but if the camera is fastened with just one screw, make sure it isn't working itself loose.

Maybe get an operator to look it over once ?

I know Lorenzo Senatore lives in Sofia ...


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#3 NOT Simon Blouin

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Posted 20 January 2014 - 11:01 AM

Hi Emilian,

 

How is your hand placed on the gimabal? Looks like your holding the gimbal too firmly. Try to relax that hand and let the rig fly itself...

 

If someone could film you while you operate we could see better what's going on.


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#4 Chris Van Campen

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Posted 20 January 2014 - 11:44 AM

How is your hand placed on the gimabal? Looks like your holding the gimbal too firmly. Try to relax that hand and let the rig fly itself...

 

As a test you could try the same kind of move using only one hand - literally take your hand off the gimbal. Looks like your gimbal hand might be introducing the rotation. If it happens without touching the gimbal/post then something else is going on.

 

You're not wired to anything like headphones or something else I'm assuming...


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#5 Emilian Dechev

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Posted 20 January 2014 - 02:29 PM

Thanks for the points!
I will try to find this Lorenzo Senatore, but I doubt he will have time to help some random students with cheap rigs and no training...

- The camera is sitting firmly on the plate.

- I tried to handle the rig without the left hand (gimbal) and the shake is still there.  I even tried to hold the gimbal firmer in order to stop it from moving, but alas, the shake is still there.

I can note, that the camera is really light, like 2kg with added weight. The drop time was 2.5sec, but these have nothing to do with random pan-shakes...

I can also note, that the arm post is of a locked type (not rotating).

Tomorrow I will try to fly the sled without the arm and vest.

Should I try walking in a narrow line, like the models on a runway, landing one foot right in front of the other?


 


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#6 Brian Freesh

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Posted 20 January 2014 - 03:21 PM

What camera are you using?  Is the OIS (Optical Image Stabilization) on? If so, turn it off. This doesn't necessarily look exactly like that, but it seems similar and could be part of the problem.  Maybe there is some friction in the gimbal. Try spinning the rig on the balance spud, does it spin smoothly (regardless of dynamic balance) or get caught at times?


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#7 Emilian Dechev

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Posted 20 January 2014 - 05:02 PM

Camera is Canon 60D, works as any other standard DSLR. No OIS. Yes the gimbal spins smoothly.
I tested the sled without the arm and well, the problem is still there, but the shakes are less.

Now I think I found the problem! - The camera is too light. There is not enough weight in the upper as well as in the bottom part of the sled.

Naturally there is always some friction in the gimbal's rotating axis. There are no frictionless materials/gimbals right... If I make a slow rotation, the gimbal wont register it and the camera will rotate. If I make a fast rotation, the gimbal will turn and the camera wont turn. In the same manner, if I put a heavy camera, the gimbal may be working smooth, but with a light camera the friction will alwyas transfer.
When wearing the vest, my footsteps transfer fast jerks through the arm, no matter how carefully I walk. So with a lightweight setup, the gimbal just cannot register all of the rotation forces.

Also the gimbal fails the 360 rotating test with a light weight on it (I rotate the sled around itself and the camera must always look forwards. But it does not - it rotates.)

So now I have to put some weight on top of that thing and lubricate it a bit.

I am not sure how to lubricate a gimbal, should I go with a regular mechanical oil, or maybe "penetrating fluid"?

Can I disassemble the gimbal so it will be easier to oil it?

 


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#8 Brian Freesh

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Posted 20 January 2014 - 05:10 PM

It should not be possible for the gimbal to rotate while the camera does not (or vice versa), they should always be in sync.  Sounds like you have slip in your system, like the gimbal itself is slipping on your centerpost. Or maybe the top stage is slipping on the centerpost.  That would certainly account for what we are seeing in the video.

 

If you are balanced, the camera is not too light. If the camera is too light you will not be able to balance it with a a reasonable drop time and/or the arm will always be lifting too high.


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#9 Emilian Dechev

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Posted 20 January 2014 - 06:55 PM

"It should not be possible for the gimbal to rotate while the camera does not"

I am not sure about terminology, maybe I couldn't explain it well. Here is the rotating test, where my gimbal fails. Watch at 10:00 -

I guess I will add some TF2 and see if the shakes will be less...  http://weldtite.co.u...th-teflon-400ml

 


Edited by Emilian Dechev, 20 January 2014 - 06:56 PM.

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#10 Brian Freesh

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Posted 21 January 2014 - 02:41 AM

Fair enough, I didn't understand what you meant.  What I said is still accurate, depending what point of reference you have. Point is, when you pan the rig, the camera pans with it.  When you do not pan the rig, the camera does not pan with it.  In a perfect world

 

If your gimbal is failing that test, we're back to what I said before - friction in the gimbal.  It may just need to be oiled, it may also not be machined precisely enough to perform very well.


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#11 Emilian Dechev

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Posted 21 January 2014 - 04:38 AM

Yes I will try oiling the thing. And I will add some weights on that camera I think, the more weight, the less friction will happen during rotation.

In case of a faulty gimbal, is there only a gimbal part that I can get to replace this one? I suppose the diameter of the sled pole, matters.


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#12 Fabrizio Sciarra SOC ACO

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Posted 21 January 2014 - 04:50 AM

Emilian, it woud be interesting to see a video of yourself operating, that could help understanding what is the problem behind.

If you could upload a few seconds it would shorten the troubleshoot I think.


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#13 Emilian Dechev

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Posted 21 January 2014 - 05:41 AM

Ok I will try to find a second camera.


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#14 Fabrizio Sciarra SOC ACO

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Posted 21 January 2014 - 09:29 AM

Your phone would do


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#15 Victor Lazaro

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Posted 21 January 2014 - 12:43 PM

By looking at your footage, I really think that the gimbal has some issues moving freely and is therefore following the orientation of the arm an of your body. when the sled is docked are you able to move the gimbal freely around the center post, or do you feel some friction/gripping in it. It should take no effort to spin around in every direction.


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