How to film computer monitor without flicker?

starman · November 6, 2004

I am in the middle of filming my latest film and for some of the shots I need to have a computer monitor in the shots. I am using a digital camcorder to make the film and we all know how computer moniters flicker when video taped... Does anyone know how to film a monitor without the flicker?

I was just going to overlay screen-captured images over top of the monitor screen during the editing but I need to film a monitor with a screensaver on it so I will need to have movement.

Please help, thanks! :)

Paul

www.carrotkid.com

Edited November 6, 2004 by starman

Preston Herrick · November 6, 2004

You can either adjust the refresh rate of the computer monitor to 1/60 second (60hz) or adjust the shutter speed of your camcorder if it has a synchro scan feature. If neither of these are options, or don't know how to do it, you can shoot a computer LCD monitor (flat panel display) and you shouldn't have any issues at all.

Michael Nash · November 6, 2004

Preston's got it. "Synchro scan" is known as "clear scan" on Sony professional cameras, and may be a separate menu item from shutterspeed, depending on the camera.

Be aware that clearscan will make the monitor image "shear" when you pan, so you might want to limit the shots with the monitor in frame to either static shots or very slow pans.

Also be aware that most computer monitors are balanced much closer to daylight than tungsten -- even LCD's. A lot of computers will let you adjust the color temperature, but rarely as low as 3200.

starman · November 6, 2004

Thank you for the responses... Unfortunately though, my camera is not a professional one and it does not have Synchro scan or a shutter speed adjustment. But thanks for the info (I now know what to look for if I ever get a new camera). Also, I set my monitor refresh rate to 60 hertz and it does not flicker anymore, however, there is now a thick blackish bar that repeatedly pans down the screen instead and the shot is still unusable.

As for panning, the shots are all still shots for it is an animation I am making so I thought I could always overlay the computer monitor image into the shot later but I would still need footage of the screensaver to do that. I tried using a 'Screen Capture' program to do that but the screensaver becomes choppy with the Capture program running at the same time.

Any other thoughts on how I could Film a monitor without interferance, or of another way to turn a screensaver into a video file? Or does anyone know of a good 'Screen Capture' program that doesn't make the screen choppy when capturing?

Thanks people, your info is much appreciated.

Edited November 6, 2004 by starman

Bob Hayes · November 6, 2004

I really don?t understand what you mean by needing a screen saver shot to use in animation. Do you mean that you plan to use a still shot of the computer screen saver and composite into you video image. If this is the case, how about taking a digital still of your computer and importing it into your graphics program.

starman · November 6, 2004

Yes, taking a still image and importing it after is what I plan to do for the other computer shots, however for the first shot there must be an animated screensaver showing on the monitor.

I'm not really taking a shot of a computer, it's more like I'm taking a shot of a desk with a computer on it in the background. The computer will be on the top half of the screen... Then, on the bottom half I will be animating my character walking along the desk over to the monitor where he will stop and look up at the screensaver. Then I will combine the top and bottom half together using split screen. Hope that makes a little more sense. Sorry, I'm sometimes not good at explaining myself. Any ideas?

The film I am making is part 3 of an animation series I have going called 'Table Kid Kirby'. If you would like to get a better idea of what I am doing you can check out the first 2 episodes at my website. The Kirby download page is: http://www.carrotkid.com/kirbydownloads.htm

Thank you for your time everyone.

November 6, 2004

Doesn't interlacing have something to do with it? I thought that was what caused the flicker..

Alvin Pingol · November 7, 2004

Doesn't interlacing have something to do with it? I thought that was what caused the flicker..

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Interlacing causes interlace flicker, or "shimmering" as some call it. It is a result of an even line (or lines) being significantly different in brightness and/or color from the odd line(s) next to it. If you want to see this in action, make a PAL or NTSC-sized frame that has alternating black and white horizontal lines, each one pixel thick. Then export this to tape and watch it on an interlaced display.

Starman's problem has to do with the refresh rate of the monitor not properly in sync with the shutter of the camera.

starman · November 7, 2004

Yes, Alvin is correct.

I was thinking... Since a monitor refresh rate at 60 hertz equals 60 refreshes per second and video cameras operate at 30 frames per second, wouldn't using a monitor refresh rate at 30 hertz be the answer? And if so, is it possible to change the refresh rate to 30 hertz? Mine seems to only go as low as 60 hertz.

David Mullen ASC · November 7, 2004

No, because a regular interlaced-scan video camera shoots 60 (59.94) times per second, only each picture is a field, not a whole frame.

Michael Nash · November 7, 2004

Any other thoughts on how I could Film a monitor without interferance, or of another way to turn a screensaver into a video file?
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I think someone already answered that -- use an LCD screen. They don't refresh the same way as CRT's, and don't cause flicker. I've got a nice 15" LCD at home, plugged in to a regular laptop.

Jon Allen · November 8, 2004

One thing that might work is turning the monitor off, and then superimposing the image on it later- this would eliminate the flashing.

starman · November 10, 2004

Yes, this is what I plan to do (film the shot first and then add the screensaver in later). However, since the screensaver has motion to it I cannot simply impose an image into the shot - it must be video file of the screensaver. The trick is turning the screensaver into a video file. I tried using a Screen Capture program which works but made the screensaver too choppy to use.

Any ideas on how to transfer a screensaver into a video file smoothly?

Jon Allen · November 11, 2004

Get a different screen capture program?

Seriously, there are a lot of ways to convert your video out to a signal you can record it to a deck or camera. I have a VGA to RCA/SVideo adapter that I could plug into any TV, camera or deck. Then just recapture from that back into your NLE. Good luck!

rpster · November 28, 2004

Check your programs in your camera and see if you have anything with slow shutter (i.e. night mode, low light) . then control lighting by manually adjusting exposure.

Chris Keth · December 3, 2004

Preston's got it. "Synchro scan" is known as "clear scan" on Sony professional cameras, and may be a separate menu item from shutterspeed, depending on the camera.

Be aware that clearscan will make the monitor image "shear" when you pan, so you might want to limit the shots with the monitor in frame to either static shots or very slow pans.

Also be aware that most computer monitors are balanced much closer to daylight than tungsten -- even LCD's. A lot of computers will let you adjust the color temperature, but rarely as low as 3200.

<{POST_SNAPBACK}>

On at least some Sony cameras (the DSR-300 comes to mind) clear scan is found by changing the shutter speed to higher speeds until it will change to a "CLS" indication and will give shutter rates in hertz. That way you can match the frame rate with the refresh rate.