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-   -   How to deal with stroboscope effect caused by room lights (https://www.dvinfo.net/forum/open-dv-discussion/94779-how-deal-stroboscope-effect-caused-room-lights.html)

David Niemeijer May 23rd, 2007 04:14 AM

How to deal with stroboscope effect caused by room lights
 
I recently shot some HD footage in a school using a PAL 1080i camera from Sony. Later, when editing the footage I noticed there was a slight stroboscopic effect on the material (a bit like what you see when shooting a CRT monitor or TV with a DV camera, but less pronounced). My guess is that it was caused by a difference between my capture frequency and some native frequency of the lights in the room. Is there any way in Final Cut Pro to correct for this. Is there a way to prvent the issue from ahppening while shooting, for example by adjusting shutter speeds or so?

Thanks,

david.

Dean Sensui May 24th, 2007 02:01 AM

If your camera has a "clear screen" feature, which is actually intended to allow the camera to sync with the flicker of computer CRT's, then that would solve the problem.

I ran into the same issue in New Zealand, using NTSC cameras under 50 Hz fluorescents.

The gelled tungsten lights we used helped mask the problem -- which went unnoticed until it was too late. That's one of the follies of rushing a setup.

By the way, there's a difference between working quickly and rushing. Rushing often leads to carelessness and mistakes.

Marcus Marchesseault May 24th, 2007 06:24 AM

Changing shutter speed can help, but it is not very likely to work. I have a method that works, but it won't work with most cameras. I can set the V1 to 1/30 shutter and shoot 30P so I still get the full framerate, but the motion blur is excessive for most purposes. No fluorescent light flickers as slow as 30 times a second, so 1/30 shutter will always work, but that's a really slow shutter and I would only use it in extreme circumstances.


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