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Exploding Television Screens

Published : 22nd April 2004


Any advice to compensate exposure when shooting a television screen? I seem to remember that the norm was to under expose a couple of stops but can't remember. Shooting 7222 so especially concerned about overexposure.

Thanks
Nick Anthony
Aspiring DP
SF



Well Nick the most common practice is to shoot at 30 frames per second, the same frame-rate as television. I know there's more complicated options, but they're more complicated.

Dave
NYC



The American Cinematographer Manual has a section on "Filming Television Screens". Frame rate, shutter angle, and the use of a synchronizing box are discussed.

You can also use a video or computer monitor that does not flicker or have a refresh (e.g., LCD monitor). Quick way to tell is to rapidly sweep your fingers between the monitor screen and your eyes -- you need to worry about sync if your fingers "strobe" as they sweep past the screen.

John Pytlak
EI Customer Technical Services
Research Labs, Building 69
Eastman Kodak Company
Rochester, New York 14650-1922 USA
http://www.kodak.com/go/motion



A basic measurement tool that I find works pretty well is to use my Canon SLR still camera as a light meter for the screen. I set the ASA on the camera to the same that I'm shooting, set shutter at 1/60th and then fill the viewfinder with the TV screen and see what exposure the still camera would use. The other way of exposure evaluation I use is with a spot meter. If you know where to point it and how to read it, it also gives reliable results. The one thing you'll have to develop an eye for though is the picture contrast of the image on the TV. You may get the right exposure for the TV, but the contrast may be wrong.

I suggest you get a still camera, a roll of slide film and shoot tests. Make copious notes as you're shooting, how you're metering, etc. and find a system/technique that works for you. Slide film (daylight) will give you an accurate representation and feedback of your exposure evaluation process. Also, read the ASC manual as John suggested.

Randy Miller, DP in LA



A good starting point would be to use a spot meter to measure the white level (or brightest white) on the television display set up to give you a visually pleasing picture. Likely to be somewhere near 40 footlamberts. Then adjust your set lighting so the reflectance from a white card in the main subject area is nearly the same. Finally, your camera exposure should be based on that level of light. Be careful not to "wash out" the video display with your lighting.

You are shooting B&W. But for color, remember that most television displays are set up for a fairly high color temperature, typically 6000K to about 9000K. Some monitors let you adjust the display white color temperature, with others, you may need to gel it down.

You need to decide if you want the color display to match the color temperature of your set lighting, or want it to stay fairly blue.

Here are some links to additional information:

http://www.inforeading.com/archive/text_files/computer_related/

photoscn.txt


http://www.cyberroach.com/analog/an30/NdUsAn30.htm

http://www.halfhill.com/video.html

John Pytlak
Eastman Kodak Company
Rochester, NY 14650-1922 USA



Read this page -  /tvscreens.htm

Something that will affect your TV exposure, or at least mine, is what you're trying to accomplish with the TV. Is it the sole light source in a dark apartment in a wide shot? Or are you shooting just the screen or pieces of it for some stylised video to film transfer? Or a family on a couch watching a sitcom? Each will probably mean a different exposure decision.

As far as contrast of the set goes, I would err on the side of less rather than more, but again, what are you trying to do? What is your source tape content?

Good luck,


Randy Miller, DP in LA



Thanks for the help.

I guess my question wasn't very clear. I am aware of the shutter angle and frame rate solutions for the flicker problem and have taken care of this, but I am more concerned about the screen itself being over exposed. I did shoot still tests but it looks like I won't get them back in time.

The film is intended to look naturalistic, like a documentary.

The scene has two shots with the TV One is a master with a guy watching it the other is a close-up of the TV. It is a day interior, the only motivated light source, other than the TV, being a large window that faces the camera, about 8' across and 6' high. No dialogue in the scene and the audio on the TV is narration. I plan to shoot this scene at 29.97 on an SR1. The footage will be telecined and never go back to film

Thanks very much for the responses.

Nick Anthony
Aspiring DP
SF