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Flicker from TV


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#1 Colin Rich

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Posted 10 November 2008 - 03:45 PM

Soon I'll be shooting a short drama with an HVX-200a at 24pn/720p in the US. Many necessary shots have standard def, NTSC tv's in them. I'm wondering if I'll get flicker shooting at 24p. Would any flicker be negated if I shot at 30p? I think a camera test will be helpful, but I don't yet have access to the HVX.
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#2 Saul Rodgar

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Posted 11 November 2008 - 02:33 AM

What you will get is the scan bar moving horizontally across the screen UNLESS you use the clear scan / shutter sync feature in the HVX200 menu. The good thing about video is that you can see the end result by just looking into the viewfinder, as opposed to film -where you don't notice anything until it comes back from the lab and SURPRISE!!
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#3 Colin Rich

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Posted 11 November 2008 - 02:12 PM

Ah, I see. Thanks!
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#4 Keith Walters

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Posted 13 November 2008 - 04:32 AM

Soon I'll be shooting a short drama with an HVX-200a at 24pn/720p in the US. Many necessary shots have standard def, NTSC tv's in them. I'm wondering if I'll get flicker shooting at 24p. Would any flicker be negated if I shot at 30p? I think a camera test will be helpful, but I don't yet have access to the HVX.

Is there any way you can use an LCD TV screen?
If you do that, you will have absolutely zero flicker or strobing problems. End of story.

Generally, if you shoot NTSC on an old CRT-type TV at 24fps and a 180 degree on film, or 24p video with a 1/48th shutter, you usually wind up with a thin horizontal flickery line slowly drifting up or down the screen
If you shoot at 30fps you'll get a faint horizontal but not flickery line slowly drifting up the screen. You actually need to shoot at 23.94 frames per second to match the NTSC frame rate. That way the line will be stationary, and you have to move it off the screen with the camera's "phasing" button (if it has one) before the action starts.

However if you shoot at 23.94fps with the equivalent of a 360 degree shutter there should be no strobing of any kind.

By the way, if you have to shoot a CRT monitor, it's only really practical to do locked-off shots. Any movement of the camera will produce weird effects on the image of the TV screen.

But again, not with an LCD. If the TV has to be in "period" you might consider getting an old junked TV and fitting an LCD screen inside it. Or if you're on a tight budget you could use a second-hand LCD computer monitor and run it off a laptop with a DVD drive. Just record your video with a DVD recorder and you can usually play that back through the laptop.
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