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shooting off an LCD tv


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#1 Frank Barrera

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Posted 13 February 2007 - 10:35 AM

Wasn't sure where to post this:

Will be shooting with S16 Aaton LTR 54, 24fps. The idea is to see the actor watching some home video on his tv. We will be shooting the video material with a Canon GL2 and then playing it back on an LCD TV that's already on location.

How do I mitigate the roll bars of the interlaced frames? We would like to see zero rolling. If I shoot the GL2 in FRAME MODE does that even help? Are there "safe" shutter speeds on the GL2 for this? Are LCD TV's better than Plasma? I know nothing about how the LCD refreshes I still have a nice 20" CRT at home.

Of course we have no time or money to shoot a test.

thanks
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#2 David Mullen ASC

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Posted 13 February 2007 - 10:50 AM

The decay time on LCD's is slow enough that flickering and roll bars should not be an issue, whether or not the material on the display was shot in 60i or 30P, etc. Just make sure it's really an LCD screen and not a plasma screen.
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#3 Frank Barrera

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Posted 13 February 2007 - 10:57 AM

Thanks Dave.

They are telling me it's LCD but what happenes if it's Plasma?
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#4 David Mullen ASC

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Posted 13 February 2007 - 11:01 AM

Thanks Dave.

They are telling me it's LCD but what happenes if it's Plasma?


Plasmas can have something like a faint 60Hz cycle pulse running through them, not a roll bar. I haven't shot them but one solution may be to just set the camera's shutter to 144 degrees so that you are at 1/60th of a second.

I was talking to our video playback tech the other day and he mentioned that with plasmas, he corrects the frame rate to 24 fps somehow (or maybe it is 48i) but doesn't have to sync it to the cameras.
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#5 Joe Sexton

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Posted 13 February 2007 - 11:46 AM

I shot a plasma before and it looked fine, but I had a 144 degree shutter.
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#6 Jonathan Benny

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Posted 13 February 2007 - 02:00 PM

Will be shooting with S16 Aaton LTR 54, 24fps. The idea is to see the actor watching some home video on his tv. We will be shooting the video material with a Canon GL2 and then playing it back on an LCD TV that's already on location.


Sounds fine. If prod design can make it work, LCD is always requested. If the playback material is video-originated, it was always shot interlaced but I've never heard of a problem with shooting progressive-shot material played back on LCD. Plasma is not as friendly in this situation.

AJB
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#7 Phil Rhodes

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Posted 13 February 2007 - 02:38 PM

Hi,

If a plasma screen flickers at some multiple of 60Hz, that's blind luck - they're driven at whatever frequency the manufacturer found most convenient.

Neither LCD nor plasma will ever produce a roll bar, though. They sometimes flicker or pulsate. It's usually not too bad.

Phil
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#8 Frank Barrera

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Posted 13 February 2007 - 04:19 PM

LCD it is. thanks all.
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