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Ryan Thomas
Recording TV screen results in banding lines...
on Jun 14, 2015 at 7:35:55 am

Hey guys, so I have a Canon 70D camera and no matter what shutter speed I use, it always results in banding lines showing on the television screen. It is an LED/LCD Samsung TV.

Is there anyway to get rid of the banding that is showing up on my video? Are there any filters that I can put on my lens to correct the issue?

Thanks for your time!

Ryan


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Ryan Holmes
Re: Recording TV screen results in banding lines...
on Jun 15, 2015 at 9:18:25 pm

Yep...the glories of a rolling shutter. So basically you're struggling with a few things here:
(1) How the 70D records video with a rolling shutter, and
(2) The refresh rate of the monitor itself,
(3) The power grid that you're plugged into to power the monitor (depending on where you are in the world power runs at different frequencies - 50Hz in Europe, 60Hz in North America)

On your 70D what shutter speed are you shooting at? What frame rate are you recording to? What is the refresh rate of your monitor? I'll be honest, that it's very, very difficult to completely eliminate this from your recordings in camera. This is why TV shows and movies will typically do screen replacements for everything. So the image appears clear and without any refresh lines appearing. Many times this is a post vfx problem. Here's a good down and dirty trick from Philip Bloom that may work in your case:


Ryan Holmes
http://www.ryanholmes.me
@CutColorPost


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Jonathan Ziegler
Re: Recording TV screen results in banding lines...
on Jun 17, 2015 at 1:20:24 am

Has to do with the shutter speed of the camera (set to 1/60) and the refresh on the TV (also set to 60Hz). May need a line conditioner to smooth out the rough edges so you always output the right amount of voltage and to be sure you are right at 60Hz (most household electrical lines vary a lot more than you'd think). Couple that with rolling shutters on DSLRs. Consider also, there are little LEDs that glow bright white behind the other color pixels on your TV which will also contribute to the banding or funky glow from TVs, neon signs, and fluorescent lighting.

I wouldn't recommend shooting it on a DSLR, but you could put some dots on the screen and use that for tracking the footage in post - one on each corner so you can track the footage and insert the TV stuff in post.

Save early. Save often.

Jonathan Ziegler

http://www.electrictiger.com
520-360-8293


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