"Jello" effect in video
2034 16 2015-5-29
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Oliver
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So my P3P arrived today, was really excited to try it out. First flight went well, took it really slowly, took some photos and video which came out well, except the video appears to have that "jello" effect I've been seeing around. What do you guys think:



I have of course taken off the gimbal lock AND the foam protector.

Anything I can do to remedy this? It was taken at 4K default settings (and has been scaled down to 1080P, though the effect was still present in the raw footage)

Could it be: shutter speed, framerate, balancing, gimbal calibration, anything you think might help even if it might seem obvious to you!

Many thanks in advance

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sinbad_uk
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Have you taken off the protective film from the lens? it looks blurry in the middle.
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Oliver
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sinbad_uk@ntlwo Posted at 2015-5-30 05:12
Have you taken off the protective film from the lens? it looks blurry in the middle.

I left it on for its first flight as I was nervous about messing up the landing and scratching it or something. Would that cause a jello effect?

Cheers
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Fulgerite
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1.  Remove the protective film.  It also has a protective glass filter in front of the lens.

2.  Use a 3 stop ND filter.  This will show the shutter and eliminate the jello effect.  You can pre-order these... http://polarprofilters.com/shop/DJI-Phantom-3-Filter  or wait for DJI to come out with a set.  Props being unbalanced and windy conditions can also contribute to jello effect.  Looks like you were flying in windy conditions.
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rerossi
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I have now received my second P3 with the same shaky video problem.  The below link is a typical video sample filmed at 1080p @ 60 fps.  I do notice alot of shake in the gimbal when the phantom is hovering in place.



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Oliver
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Fulgerite Posted at 2015-5-30 05:25
1.  Remove the protective film.  It also has a protective glass filter in front of the lens.

2.  Us ...

Thanks for the suggestions, are replacement protective glass filters available? Just incase!
Also thanks for the recommendation of an ND filter. I'm a little confused at how the ND filter removes the jello effect - what do you mean by "show the shutter"?

Is there any way I can check for prop balance or do anything about it? And yes it was a bit windy at times, strong gusts from time to time so I suppose that makes sense. How does wind contribute, out of interest?

Thanks for your help
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Oliver
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rerossi Posted at 2015-5-30 05:52
I have now received my second P3 with the same shaky video problem.  The below link is a typical vid ...

That looks like something more serious - did you remember to take out the foam?
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Fulgerite
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Oliver Posted at 2015-5-30 07:24
Thanks for the suggestions, are replacement protective glass filters available? Just incase!
Also  ...

I mean SLOW DOWN the shutter speed.  Using an ND forces the camera to pick a slower shutter speeds.  This drastically reduces the rolling shutter effect.  (Jello)

There are hundreds of threads on the DJI forum that talk about the use of ND filters and how it helps reduce the jello effect.

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Oliver
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I see, thanks for the explanation and example. I feel a bit silly for missing that key component! Out of interest, isn't there a way to manually limit the shutter speed in the camera settings? If so, wouldn't that solve the problem?
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Fulgerite
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Oliver Posted at 2015-5-30 07:55
I see, thanks for the explanation and example. I feel a bit silly for missing that key component! Ou ...

The lens has a fixed aperture of f2.    No iris.  (GoPro suffers from the same issue.  No iris.)

At ISO 100 you still need to be at something like 1/3200th of a second due to the fast lens thats wide open.   Using an ND filter will push the shutter down to something like 1/200th.  This drastically reduces the rolling shutter effect.  I think shooting around 1/100th or 1/200th is ideal.

The slower shutter speed also adds a touch of motion blur that reduces the strobing effect as well.  And the slower shutter speeds help reduce prop strobe as well.

ND filters are a "must have" accessory for these cameras that have fixed aperture lenses.
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Oliver
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Fulgerite Posted at 2015-5-30 08:05
The lens has a fixed aperture of f2.    No iris.  (GoPro suffers from the same issue.  No iris.)

...

So the end goal is to slow down the shutter speed, and in order to do so without overexposing the image we effectively need to reduce the amount of light incident on the sensor by using a filter. Right, makes sense, thank you for the info!
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Fulgerite
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Hope the info was helpful.


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rerossi
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Oliver Posted at 2015-5-30 07:25
That looks like something more serious - did you remember to take out the foam?

Thanks a bunch.  I did not notice the foam in the back of the Gimbal until just now.  I will try a second flight tomorrow and see what happens, but based on what I can see now, I would say it was the foam causing the problem.  I am just amazed that technical support at DJI never suggested I check the foam packing.
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Fulgerite
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Yes.  REMOVE that foam.  Your problem will likely be more tolerable.  Also remove the plastic protector film from the lens.
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sinbad_uk
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Don't forget to calibrate the IMU/Gimbal. there is loads written about that already.
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Oliver
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sinbad_uk@ntlwo Posted at 2015-5-30 13:42
Don't forget to calibrate the IMU/Gimbal. there is loads written about that already.

Just flew for after calibrating the gimbal, seems to have helped though I was flying in lower lighting conditions so that may have reduced the shutter speed anyway

Thanks for the suggestion
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rerossi
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Oliver Posted at 2015-5-30 07:25
That looks like something more serious - did you remember to take out the foam?

Thanks a million.  The foam was in there and removal did improve the video dramatically!
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