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T.V. Scenes on 16mm


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#1 Pedro Millan

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Posted 22 April 2007 - 07:14 PM

Hey,

I will shoot a low budget shortfilm in 16mm with an Arri SR III. There are some scenes where the charachters are watching T.V.
My question is how to shoot these scenes? Of course i want to see the images on the T.V. really clean and without the lines.
It is the fist time i will shoot some T.V. scenes and i am doubting if a should change the angle shutter or change the fps at 29.97? and whats the difference between the 24fps scenes and the 29.97fps scenes?

Thanks guys,

E.P.
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#2 Kenny N Suleimanagich

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Posted 22 April 2007 - 07:28 PM

I worked on a film where we had a shot of the TV and we used an SRIII, the great thing about the SRIII is it has variable shutter, so you can (and should for NTSC TV) change the shutter angle to 172.8° to avoid rolling bars.
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#3 David Mullen ASC

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Posted 22 April 2007 - 07:52 PM

144, not 172.8. I believe the 172.8 shutter angle is for shooting at 24 fps under 50 Hz lights, or shooting a PAL TV set, since at 24 fps, it gives you a 1/50th shutter speed.

If you are shooting a 59.94 Hz NTSC CRT screen at 24 fps, then closing down the shutter from 180 to 144 degrees will make the thick roll bars into thin lines that roll.

If you shoot at 23.976 fps, then the thin lines now (from the 144 degree shutter angle) will stop rolling. But you will need to adjust the phase in order to move the lines to where you want them -- usually your choices are two lines, one at the top third and one at the bottom third of the screen, or only one line, but dead center. Usually you use a film-video sync box to adjust the speed to 23.976 fps and adjust the phase, but the Arri SR3 may have those controls built-in.

If you don't want any lines, you either need to use special 23.976 fps video monitor and playback equipment, or you need to shoot at 29.97 fps. I think you still need to adjust the phase to get the camera frame to line-up with the video frame.

Trouble with shooting at 29.97 fps is that when it is played back at 24 fps, it becomes slightly slo-mo, and you can't do sync-dialogue in the same shot as the TV screen.

The easiest thing is to use an LCD screen for the TV, which doesn't have any sync or roll bar issues, just shoot at 24 fps.
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#4 Clive Tobin

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Posted 22 April 2007 - 07:58 PM

...Of course i want to see the images on the T.V. really clean and without the lines....

Assuming you are in the USA and can change your shutter angle:

If you film at 29.97 FPS you would want a 180 degree shutter opening. This will give a stationary bar somewhere in the frame. If you have a Phase button you can move it to where you want. Actually if you film at half speed 14.985 FPS you will get all the scanning lines instead of every other one.

If you film at 23.976 or 24 FPS you would want a 144 degree shutter opening. Actually if you film at 12 or 11.988 FPS you will get all the scanning lines. There will be a "splice" occurring every second frame, half a frame above or below where the first one is in the video frame. This gives a flickering effect in two places on the video screen and might be more noticeable than the first method.

172.8 degrees is wrong for the USA. This is for filming from a 25 FPS monitor at 24 FPS, or for filming under 50 Hz HMI lights at 24 FPS.

Most people these days (with an adequate budget) are instead buying a flat-screen plasma or LCD TV set. You should be able to shoot from this at any speed you feel like, since it it not scanned like a picture tube. Test first to double check.
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#5 Kenny N Suleimanagich

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Posted 22 April 2007 - 08:09 PM

ALSO, teh SRIII I BELIEVE has a 23.97 setting you can use, in addition to 29.97

Edited by Kenny N Suleimanagich, 22 April 2007 - 08:10 PM.

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#6 Pedro Millan

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Posted 22 April 2007 - 08:24 PM

If you have a Phase button you can move it to where you want.


Thanks for the help.
Yes, its gonna be NTSC 59.94Hz.
I wish i can do some tests but i am afraid that wont be possible.
In that case, i guess the right thing to do is to shoot at 24fps with a 144 degree shutter angle and adjust the line where i want it.
But i still have a question, the phase button to adjust the line is actually on the camera SRIII, right?

Thanks a lot guys,

Ernesto Pitt
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#7 Kenny N Suleimanagich

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Posted 22 April 2007 - 08:28 PM

Thanks for the help.
Yes, its gonna be NTSC 59.94Hz.
I wish i can do some tests but i am afraid that wont be possible.
In that case, i guess the right thing to do is to shoot at 24fps with a 144 degree shutter angle and adjust the line where i want it.
But i still have a question, the phase button to adjust the line is actually on the camera SRIII, right?

Thanks a lot guys,

Ernesto Pitt


Yes it is on the camera, sorry for misleading you earlier by the way my mistake.


I suggest picking up a copy of the "Arriflex SR Book", very useful for stuff like this, as well as the ASC Manual.
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#8 Pedro Millan

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Posted 22 April 2007 - 08:35 PM

Yes it is on the camera, sorry for misleading you earlier by the way my mistake.
I suggest picking up a copy of the "Arriflex SR Book", very useful for stuff like this, as well as the ASC Manual.


Dont worry Kenny, your posts have been very helpful,
thanks,
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#9 Will Montgomery

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Posted 23 April 2007 - 06:45 PM

I believe shooting a new LCD type tv might also eliminate that problem.
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