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Does anyone know how to avoid this issue when filming screens?


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#1 Yash Lucid

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Posted 30 May 2017 - 05:10 AM

Shooting 4K 1/50 on GH4.

Need a tracking shot.

Tried CPL.

Tried defocusing but that only works when you're static.

 

Is this a fix in post only issue?


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#2 Brian Drysdale

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Posted 30 May 2017 - 06:36 AM

What is the issue that you're trying to fix?


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#3 Yash Lucid

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Posted 30 May 2017 - 07:28 AM

What is the issue that you're trying to fix?

Sorry, the attachment didn't show for some reason.

 

ez0WvZM.jpg


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#4 Macks Fiiod

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Posted 30 May 2017 - 08:37 AM

A lot of times the screens are added in post for a perfectly clean look. At times I find myself getting lazy and adjust the focus at just the right spot so it doesn't pick up the scan lines. Be thankful we still don't live in the age of CRTs:

fb6ab2a347b02ec3ba48ec3a87f9667a.png

 

That scan phasing represents an entire era of youtube before people figured out capture cards.


Edited by Macks Fiiod, 30 May 2017 - 08:38 AM.

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#5 Phil Rhodes

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Posted 30 May 2017 - 10:24 AM

You can put some very fine frost over the display, depending on your tolerance for blurring it.


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#6 David Mullen ASC

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Posted 30 May 2017 - 11:09 AM

Yes that was my thought too, maybe some 1/4 Hampshire Frost...
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#7 George Ebersole

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Posted 30 May 2017 - 11:26 AM

If it's an Apple there's actually some kind of "cinematic" setting for the display that allows the user to change the frequency specifically to film the monitor.

 

PC's allow you to change the frequency on the display, but for different reasons.  Advanced third party video cards will have a "force refresh" frequency setting that should clear up your screen effect (it'll also eliminate the scan line).


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#8 David Mullen ASC

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Posted 30 May 2017 - 11:31 AM

On a flatscreen there aren't scan lines, he's getting moire from the fixed pixel grid of the display interacting with the fixed pixel grid of his sensor. He could find a better camera that has less moire issues...
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#9 Satsuki Murashige

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Posted 30 May 2017 - 02:04 PM

Honestly, it's probably easier to just replace the screen in post. That's what most of the big smart phone and tablet ads do.

If you leave the screen plain white, it should be easy to track as long as you see the entire black screen bezel for the whole shot. That would simplify your key and help retain some realistic interactive lighting in the shot.

If you lose the bezel on your camera move, then you'll need to add tracking markers to the screen which will then need to be keyed out separately or rotoscoped. One thing you can do to avoid this is to shoot wider than the intended final image, so that you can use the extra image area for tracking. Then just crop to the desired frame after the shot is composited.
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#10 George Ebersole

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Posted 30 May 2017 - 02:26 PM

On a flatscreen there aren't scan lines, he's getting moire from the fixed pixel grid of the display interacting with the fixed pixel grid of his sensor. He could find a better camera that has less moire issues...

 

I was confusing Mack's Fiiod's pic of a CRT with the OP's issue.  Otherwise, yeah, LCD's work differently. 


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#11 Robin R Probyn

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Posted 30 May 2017 - 06:34 PM

I guess you have tried already.. but sometimes changing the focal length can help bit with morie .. that camera is probably pixel skipping or some such skullduggery in video mode.. this will be adding to your problems.. can you try a "better" camera.. 

End of the day the only way to get a really clear image is to put in it in post.. not so difficult these days I guess as we even do it alot on the small corp shoots that i do.. 


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#12 Adrian Sierkowski

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Posted 30 May 2017 - 06:44 PM

We almost always add the screen in post as well. Typically knowing the resolution of the screen before hand we'll makeup some proper green-screen images with track marks on them. For cell phones I recall once seeing an iphone app the art dept had loaded up.


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#13 Keith Walters

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Posted 30 May 2017 - 10:33 PM

You could always shoot it on film! :rolleyes:  
But generally, the problem with stills cameras used as video cameras is that the Optical Low-Pass Filter is designed for the highest-resolution stills it can take, and that's not usually appropriate for the inevitably lower resolution video modes.

A purpose-designed video camera on the other will normally hand have an OLPF "tuned" to the maximum video resolution possible.

So, as others have said, there is no real solution other than painting the screen green and Chroma Keying.


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