Canon 5dMK3 lens wobble on tilt action

Discussion in '3 Axis Gimbal' started by Chris J Ayres, Aug 11, 2013.

  1. Chris J Ayres

    Chris J Ayres Member

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    Hi,

    I have a cinestar 3 axis with radians. I have been having a terrible rapid vibration on my footage, almost like the camera goes in and out of focus. I have read the forum and done almost everything possible. Props are perfectly balanced,camera is perfect balanced (no belts), radians gains are tuned etc. But even with the 3axis off the heli and on the table on a stand, I can see when I tilt the camera up and down the lens wobbles (small vibrations), and this is ruining any footage. It seems to be the servo that may be the problem, although they are brand new.

    Near then end with this technology.....any help appreciated.

    Chris.
     
  2. Chris J Ayres

    Chris J Ayres Member

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    Update. I am wondering if the 24-105mm lens may be the problem as it is quite long and could be a or the source of the wobble. I have mounted a piece of stiff foam under the lens on the camera bracket and then firmly tied zip ties around the lens and under the camera mount to effectively anchor it down. No when tapping the lens the response is certainly deadened. When the wind drops later I will attempt another test to see if things have improved. Update coming later...fingers crossed.
     
  3. Steve Maller

    Steve Maller UAV Grief Counselor

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    That lens is not a great one to fly. Try a light prime lens.
     
  4. Gary Haynes

    Gary Haynes Administrator
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  5. Chris J Ayres

    Chris J Ayres Member

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  6. Chris J Ayres

    Chris J Ayres Member

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    Is there a lens you recommend? Presume something lower mm range but not too wide? and with IS? or not?
     
  7. Chris J Ayres

    Chris J Ayres Member

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    Perhaps a EF 35mm f/2 IS USM?
     
  8. Dave King

    Dave King Well-Known Member

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    EF 24MM f/2.8 IS is what I use. It's seems to be perfect for me using Canon 7D and the cropped sensor. So maybe you will like the 35mm lens. I know several others that run the full frame sensor and the 24MM lens and they really like it. It all depends on how what you are planning on shooting.
     
  9. Steve Maller

    Steve Maller UAV Grief Counselor

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    I fly with either the 24/2.8 IS or the 17-40L (at the wide end) on a 5D Mark III. I use the 24 for video and the 17 for stills.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Can you verify that the vibrations still occur with the Radian's in Mode OFF, Chris?
    If they do, then the vibrations are indeed something mechanical. If the vibrations stop, then it might be that you have the tilt gain set too high.

    Can you also confirm that you have the camera properly balanced on the gimbal?

    Andy.
     
  11. Gary Haynes

    Gary Haynes Administrator
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    Chris, if it is primarily on tilt check the tilt belt tension and also the small allen set screw that attaches the large pully to the tilt shaft. That does loosen up. There is no flat spot on the tilt shaft so it will creep if it is loose.
     
  12. Chris J Ayres

    Chris J Ayres Member

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    Andy, I intend to try with the CS3 off tomorrow. Tilt Gain set at 80%.
     
  13. Chris J Ayres

    Chris J Ayres Member

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    Gary, Belt is tight and srew is also very tight. Incidentally how tight should the belt be?
     
  14. Gary Haynes

    Gary Haynes Administrator
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    Only a small amount of deflection. I've seen 1-3mm as a guide.
     
  15. Chris J Ayres

    Chris J Ayres Member

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    Testing today revealed that the problem has all but gone away by placing some foam under the lens and zip tying it down. So my conclusion is that the 24-105 lens is too long and heavy. Ordered a 24mm prime. Thanks for all the input.
     

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