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Red Epic on old T.V. Screens


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#1 zachary holloran

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Posted 18 April 2012 - 11:25 PM

I'm shooting another short narrative film on the RED EPIC and wanted to know if there is any vignetting or scan lines when shooting live/practical television screens. Rather than compositing the video in post, I would like to shoot practically and may not have time for a test shoot. The T.V isn't a flat screen - it's an old box T.V. Anyway - any suggestions or ideas would be greatly appreciated as far as settings on the camera to avoid any distortion or settings on the t.v. that would provide for a clearer image. Thanks a lot guys I appreciate it.

-zach
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#2 David Mullen ASC

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Posted 19 April 2012 - 11:25 AM

This is a basic cinematography problem that used to be commonplace (and annoying.)

CRT screens showing NTSC video run at 59.94 Hz / 29.97 fps.

So at 24 fps with a 180 degree shutter on your camera, you get a roll bar (you actually get two I think but mainly see one).

If you set the shutter to 144 degrees (1/60th of a second shutter speed) at 24 fps, the roll bar becomes a thin rolling line, which is fine for most wide shots.

If you run the camera at 23.976 fps with the 144 degree shutter, and have a way of phasing the shutter to the TV set (used to do this with a film-video sync box, I guess on the Red it would involve playing with the electronic shutter phase), then you can get the thin line to stop rolling. With phasing, you either can get a single thin line sitting in the center of the screen, or two lines near the top & bottom of the screen.

That's it.

Beyond that, either you need to actually shoot at 29.97 fps (180 degree shutter would be fine) but then may have sound sync issues if there is dialogue during the scene if the project is 24P... or you need to contact a company that does 24fps monitor playback, in which case they bring a special TV set that runs at 23.976 fps and you have your material converted to 23.976 fps video and they bring a special playback deck for that video. Then you'd just shoot at 23.976 fps with a normal 180 degree shutter and phase to the TV set.
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#3 zachary holloran

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Posted 20 April 2012 - 02:16 PM

Awesome. Exactly what I needed to know. Makes sense with the shutter - I figured it'd be something along those lines thanks so much David! Always love your help.
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The Slider

Media Blackout - Custom Cables and AKS