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Weird footage artifacts: footage seems "Wavy" or to be "dancing"

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Robert van Halteren
Weird footage artifacts: footage seems "Wavy" or to be "dancing"
on Oct 1, 2015 at 9:17:16 am

Hi there,

The company I work for uses a simple pocketcamera placed on a simple tripod to film some of their activities. They recently purchased a new camera (samsung galaxy 2 camera) and it has some weird artifacts.

It's a construction company that drives steel sheet piles into the ground. They do this using a high frequency (vibratory) hammer. This obviously has effects on the ground/soil: it will shake/vibrate a bit too.

Now, with the older camera this shake was noticeable (varying from none to a little to substantial depending on the distance) as a sort of regular shake. However, with this new camera the footage seems to "sway" or "dance" a bit. If it's placed really close to where they are working the footage is worthless. Further away is not as bad but still rather noticeable. I've tested this with the camera on my iPhone and Ipad as well and they do the same.

Does anybody have any ideas what may cause this. Obviously it's the vibrations, but i'm just wondering how they translate into this particular type of footage. At first I thought the image stabilizer might be causing it but turning it off made no difference. My next guess was that it could be a framerate/shutter speed issue. Being that the particular framerate and shutter speed combined with the very specific vibrations in the soil causes it (sort of like the rotors of a helicopter seeming to rotate in the opposite directions due to a specific framerate). However that seems a bit like a long shot.

Any Ideas??


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Steve Kownacki
Re: Weird footage artifacts: footage seems "Wavy" or to be "dancing"
on Oct 1, 2015 at 12:44:47 pm

My guess is the rolling shutter of the camera. Curios if you turn the camera 90 degrees, do you get the same effect? https://en.wikipedia.org/wiki/Rolling_shutter

Premier CS6 and above have a repair tool that may help.
http://tv.adobe.com/watch/learn-premiere-pro-cs6/rolling-shutter-repair-in-...

Steve





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Mark Suszko
Re: Weird footage artifacts: footage seems "Wavy" or to be "dancing"
on Oct 1, 2015 at 1:54:12 pm

Yep, sounds like "jellocam" effect to me. You could use a camera with a CCD image sensor, versus the CMOS sensors common today. Or, as mentioned, there are some tools to help correct it.

The "simple" tripod offers no vibration isolation. If you stick with this camera, you'll need to create some kind of suspended or floating shock mount.


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Todd Terry
Re: Weird footage artifacts: footage seems "Wavy" or to be "dancing"
on Oct 1, 2015 at 2:25:25 pm

The other guys beat me to the punch, but my guess as well is this is a rolling shutter issue.

If you can post or link to a clip a rolling shutter issue could probably be identified instantly (it has a very distinctive look).

If that's the case, this would be a job for a camera with a global shutter instead.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Robert van Halteren
Re: Weird footage artifacts: footage seems "Wavy" or to be "dancing"
on Nov 26, 2015 at 12:58:46 pm

Hi Todd,

I've made simple comparison between the Samsung Galaxy 2 Camera and my GoPro:







I figured it was a rolling shutter issue also... But the shake in the samsung is so extreme I
figured it could also be a stabilizer issue that due to the specific vibrations makes the
footage go crazy.

Btw, the first shot is the Samsung (sometimes the shake is less significant because i lifted
up the tripod) and the second is the GoPro


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