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Wobbly Video Footage

Discussion in 'Inspire 1 Help' started by Wing Commander Smyth, Oct 3, 2015.

  1. Wing Commander Smyth

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    Hi All

    I have searched on here for quite a while, and can see that people have had the same issue as me, but I have not seen a definite answer as yet....

    My issue is wobbly video footage, especially on breezy days, and I wonder if there is a solution for it or if that is simply the limits of the system, and therefore I should just live with it.

    It worries me as it means that I can't guarantee quality footage for clients every time...well whenever there is a breeze at the time of filming - which lets face it, will be pretty often here in the UK!

    Check out the video clip here to see what I mean - it happens when the hotel comes into view...



    Thoughts on the issue and how to fix it would be ace!!
     
  2. The Editor

    The Editor Moderator
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    Leaving aside the wobble, in that one shot alone how have you managed to stay within CAP722 articles 166/7?
    The people sitting on the cliff, the guy under, the windsock, the tennis court and all the properties where under your control?
    Just curious.
     
  3. Wing Commander Smyth

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    Hi there

    Yes, I thought someone might comment - but yes, they were all under our control.

    We were shooting for the hotel which is on a private island, so the chap under the windsock (Nick) is our observer - the guys on the court were staff members, the chaps not he cliff were also staff and crew from my team - the two on right are actually my goodself and my camera op, so in short - all was in accordance with what was outlined when doing the training and getting the CAA approval.

    So any thoughts on the wobble?
     
  4. The Editor

    The Editor Moderator
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    In that case - nice shot. :p

    OK, moving onto your wobble.

    • Have you checked/balanced your props
    • Do you have excessive play in your arms where the arm leaves the t-tube connector (there should be a little but not excessive)
     
  5. Wing Commander Smyth

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    Hi

    Thanks - yes it took a faaaiiirrr bit of organising to pull off but I think it worked out well.

    That's why I was uber gutted when I saw the "wobble" in the shot....

    I had balanced the props the day before, so I don't think that is it, but I could be wrong!

    However - on that very shoot, around midday - I did discover the nut on one of the forearms had become loose - not massively loose but moveable with my fingers. Do you think that could have been it? I assumed the cause would be a gimbal issue but maybe not....

    I have since tightened the nut and its remained tight, but i've not done any lengthy filming/flying since then - so I can't say if it's still doing it.

    The other thing that confused me a bit was the "wobble" is only on that particular shot, and not on any of the other 3/4 shots we did after it.....but they were much less dynamic so maybe that's why??
     
  6. InterMurph

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    I don't think I see a wobble. But I do see jello, on the hotel as you pass over it. Is this what you are talking about?
     
  7. Wing Commander Smyth

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    Yes - exactly!

    I think the vertical sides of the hotel show it up more - but I wasn't sure it was a rolling shutter issue (thats what you mean by jello right??).
     
  8. InterMurph

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    Yes, the jello is caused by a combination of vibration and rolling shutter.

    It can be ameliorated by the use of ND filters, to get the shutter speed lower. But ND filters can't really eliminate it.

    It's the job of the gimbal to eliminate the vibrations. I have experienced similar problems in high winds. The X3 gimbal is good, but it's not perfect.
     
  9. Wing Commander Smyth

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    ah I see - so yes, that is starting to make sense....

    I had the stock ND filter on it - but as it was super sunny I had the shutter speed up something crazy but I didn't think about that....I kind of had no choice.

    I had seen others mentioning the limitations of the gimbal in windier conditions, so that must be it.

    I was just wondering if there was anything I could have done differently to get a better result.......other than not fly in those winds of course!

    Thanks!
     
  10. InterMurph

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    I would try the SRP ND filters. I use the 3-stop filter on almost every flight, and I think it works very well.
     
  11. The Editor

    The Editor Moderator
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    Semantics - but the jello is being caused by vibrations being fed through to the gimbal/camera.
    I am going to assume you shot this at 25fps rather than 50 and did you keep the shutter at 1/50th sec or did it creep higher.
    I think your problem has been caused by a combination of things.
    1. Possible resonant vibration coming through the airframe from loose arm you discovered on the day
    2. A crosswind coming across the gimbal whilst it was doing a pan at the same time as a fairly high speed aircraft move.
    Bit of a perfect storm so to speak.
     
  12. Wing Commander Smyth

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    OH OK cool - thanks for the info - I will check them out!
     
  13. Wing Commander Smyth

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    Thanks Editor

    Yes it was 25p but....Ummm did it "creep" over 1/50th.........well yes, like.....a lot! I think it was something like 800?!?! I had to as it was so bright - but i'm thinking some stronger ND filters are called for here!!!

    Fingers crossed the arm tightening will help anyway!

    Personally, I am thinking the gimbal just couldn't cope with the aircraft speed with wind speed with camera move......with this in mind, do you think the X5 and X5R will suffer same or WORSE issues as they have much bigger surface areas for the wind to buffer!!!??

    What do you think???