shooting television on film

bobby singh · February 15, 2004

i am shooting a film on anamorphic where in quite a few scenes there is television on in the frame. i was wondering if i shoot at 25 frames at172.8 shutter would i be able to avoid horizontal lines. Also will it affect the image in terms of horizontal lines again if i trolly or say zoom in to the TV. I am in india we have PAL format here.

Alvin Pingol · February 15, 2004

If you are shooting at 25fps, set the shutter angle to 180 degrees. In PAL, the refresh rate for a television is 50Hz, thus a 1/50th shutter (180 degrees at 25FPS) will sync with the TV, and the horizontal bar should disappear (or become very small).

Max Jacoby · February 16, 2004

If you are shooting with Arri cameras, get an ESU from the rental house. This unit will allow you to dial out the horizontal bar from the TV screen. You'll have to shoot at 25fps and 180° shutter as perviously mentioned.

Max

Manu Anand · February 16, 2004

Dear Bobby,

Whenever we have had to shoot a TV in India or had the Tv as part of the frame we have kept the frame rate at 25fps and the shutter at 180 degrees.

you keep the shutter at 172.8 when your shooting at 24fps becuase then your shutter speed is 1/50th which is the same frequency as the Pal signal 50 hz(i hope my calculations are correct) :unsure:

the easier method has alwasy been to just shoot 25fps at 180 degrees

Now it does work on a hit and run method because you will get a static bar(which is the blanking pulse)but that static bar may still be seen on the TV.

The idea is to not see the bar at all, this is done by hit and run.

Once the bar becomes static you have to switch your camera on and off(in case the bar is in frame) until the horizontal bar is not in your frame. check this on your video assist, but remember each time your taking a shot you will have to ensure that the bar is not in the centre of the tv.

Just by setting 25fps and a 180 degree shutter doesnt ensure that the bar is not there.

We had no access to an ESU in Delhi so we did things the hard way but it worked fine , although we lost some footage ensuring the bar was not there by having a few false starts at the beginning of each shot in which the Tv was in the frame.

Manu

New Delhi

:unsure:

Luke Prendergast · February 16, 2004

I don't know the technical aspects of viewfinder/video assist/prism splitting/reflex systems in motion picture cameras, but I think switching the power on and off will only reset the phase relationship of the video assist and the television. It won't affect the film side of things. If the camera is not running, and you're not seeing what's on the film side of the shutter, you won't know whether the blanking bar is present in your image.

Switching the camera on and off is the poor mans' version of 'Clearscan' or 'Syncroscan' in the video world. If you're using a video camera of the same video standard, ie., PAL/NTSC, as the monitor/TV in the shot, this method works well, though it's not as convenient as the 'phase' button of course.

LCD monitors are fine at whatever frame rate and shutter speed/angle (at least normal rates). Computer CRTs will come out if the refresh rate is set to a multiple of the frame rate/video field frequency, but you will need to experiment a little. I have found 100Hz refresh rate to be the least problematic for PAL video.

H

Manu Anand · February 16, 2004

Dear John,

The logic that i was given by the DP as to why the bar when not seen on the video assist wont be seen on the film as well was that when the blanking pulse is out of the frame(top or bottom) it stays out on the film side as well; regardless of whether it was a beam splitter or a reflex system (this he said was his experience), and it did work.

But i do understand what your saying, and am in fact intrigued.

Off to do some research

Manu"sometime forgets that WYSIWYG doesnt always hold"

Michael Nash · February 17, 2004

Silly question, but I've never put it to the test.

Can you photograph an NTSC image displayed on an LCD multi-synch monitor without flicker (24fps/180 shutter)? I'm thinking of a standard video image fed live to a multi-synch desktop computer monitor.

Common sense tells me it should work, but I'm unclear on exactly how the monitor converts and displays the NTSC signal. I was surprised to read in AC that the background plates for process shots on the show "24" are shot with a 60i PD-150 and projected with an LCD projector to get around flicker issues.

bobby singh · February 18, 2004

thanks guys.

in fact did i some reasearch on my own also and found out that if you shoot on arri435ES it simple , you start rolling the camera and hit the phase button till the bar rolls out release the button the horizontal bar stays out, but this only happens till you cut , for the next shot you have to repeat the process, this is better than hit and run cause i have tried the hit and run it is time consuming and also expensive, also it is not WYSIWYG. Some times you may not see the the line on the moniter but it may appear on film. For hit and run you have to or rather should set it from the view finder.Also the footage being played on tv should be in DV or beta easier to sync it VHS is a problem

Luke Prendergast · February 18, 2004

From my experience an LCD monitor won't suffer phase/blank line/sync issues. Every pixel is on all the time, unlike a CRT which is being scanned by an electron gun (or three) one pixel at a time, relying on the remanence (?) of the screen phosphors and the eye to smooth things out. Other LCDs though, such as in clocks, do use a sequential scanning of each segment so you get the same kind of pulsing as in LED displays. Someone has touched on this in another post.

A side note: LCDs run on AC, so if that AC is coming clocked off the mains you may run into some problems shooting at high frame rates; same issue using HMIs. Again this isn't a problem with LCD computer monitors.

H