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How to get rid of TV strobing on a 180 degree shutter


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#1 Stephen Whitehead

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Posted 14 February 2007 - 06:56 PM

Hey, Is there a way to get rid of television strobing while using a 180 degree shutter at 24 fps?

Cheers,

Steve
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#2 Michael Nash

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Posted 14 February 2007 - 07:19 PM

Yes, shoot an LCD instead of a CRT, or create a special 24-frame playback.
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#3 David Mullen ASC

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Posted 14 February 2007 - 07:26 PM

By "strobing" I assume you mean roll bar.

At 24 fps with a 180 degree shutter, you'd need a special 24 fps CRT monitor and 24 fps playback system and tapes converted to 24 fps (and it would actually be 23.976 fps and you'd need to adjust your camera to that speed with a film-video sync box.) Basically you hire a 24-frame playback expert with their own gear.

Or shoot an LCD screen, as Michael says.
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#4 Bipin Varma

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Posted 05 April 2007 - 12:46 PM

By "strobing" I assume you mean roll bar.

At 24 fps with a 180 degree shutter, you'd need a special 24 fps CRT monitor and 24 fps playback system and tapes converted to 24 fps (and it would actually be 23.976 fps and you'd need to adjust your camera to that speed with a film-video sync box.) Basically you hire a 24-frame playback expert with their own gear.

Or shoot an LCD screen, as Michael says.



Is it possible to remove it in 172.8 shutter angle...!
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#5 David Mullen ASC

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Posted 05 April 2007 - 01:20 PM

Is it possible to remove it in 172.8 shutter angle...!


I think 172.8 is used when shooting at 24 fps under 50 hz lighting (maybe when shooting a PAL monitor too, although the safe thing would be to just shot at 25 fps), because it works out to be a 1/50th shutter speed at 24 fps.
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#6 James Steven Beverly

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Posted 05 April 2007 - 10:45 PM

Wouldn't using a PAL monitor greatly reduce the problem? After all it 25 FPS, shooting at 25 FPS should eliminate it completely. or simply shoot at 30 fps on a standard monitor. B)

Edited by James Steven Beverly, 05 April 2007 - 10:46 PM.

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#7 David Mullen ASC

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Posted 05 April 2007 - 10:59 PM

Wouldn't using a PAL monitor greatly reduce the problem? After all it 25 FPS, shooting at 25 FPS should eliminate it completely. or simply shoot at 30 fps on a standard monitor. B)


The trouble is when you have 24 fps sync-sound dialogue scenes happening with the TV in the frame, or the TV image itself has someone speaking on it. You could probably deal with shooting a PAL TV at 25 fps and just playing the footage back at 24 fps, but playing back 30 fps footage at 24 fps definitely doesn't work for sync-sound.
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#8 James Steven Beverly

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Posted 06 April 2007 - 12:54 AM

The trouble is when you have 24 fps sync-sound dialogue scenes happening with the TV in the frame, or the TV image itself has someone speaking on it. You could probably deal with shooting a PAL TV at 25 fps and just playing the footage back at 24 fps, but playing back 30 fps footage at 24 fps definitely doesn't work for sync-sound.


Sure you could, have the announcer breath in helium before the take, then when you slow it down to 24 FPS he'll sound normal or just get an announcer with a REALLY high voice :D What if you compressed the TV video footage to 35 FPS in an editing program like Premere so that it would look and sound like fast mo then retime that footage with a retiming program to 30 FPS then film it at 30 FPS project it at 24 FPS. The extra phantom 5 FPS would compensate for the 5 FPS loss during projections and sync should be mainatined at a normal vocal level, particularly for the short piriod that a shot of TV footage in the context of a motion picture would be on screen.
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