Camcorders forum


how to prevent rolling shutter?

by zornzero / May 17, 2014 7:11 PM PDT

Hello, I'm not a professional photographer.

I'm trying to record my laser beam shows with a Canon 600D camera. I can't get rid of the rolling shutter effect caused by rapidly moving laser beams!
Here's what a laser beam show looks like:

I've tried setting the shutter speed as low as possible, tried changing the fps, nothing helps...

I don't think there's even an affordable CCD camera these days I can purchase from what I've been told.
I've got this old big video camera which I think has a CCD sensor but it's a VHS camera!

What can I do? This has become extremely frustrating.

if you think knowing how these laser devices work will help you find the answer, then here's a simple summary:

There's a single RGB laser beam
The beam is hitting two tiny mirrors which can move very fast
The mirrors can move as fast as 24000 - 60000 times per second
So the multiple beams or moving beams is caused by the fact that those mirrors are moving that single beam so fast our eyes can't catch up.
The beam is very bright, if not moving it can light up a candle in a second, so it is set up to never reach the eyes and camera lens.

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All Answers

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Sounds like you want to talk about persistand of vision.
by R. Proffitt Forum moderator / May 17, 2014 10:04 PM PDT

The camera's sensor is unlike the human eye and as such you will capture something different than the human eye. I see you tried lower FPS but most devices don't have something as slow as the human vision system. I must defer to the textbooks how that works but CCD works differently from CMOS and there are other types of sensors too.

Frankly I think your video is fine for a product demo. But to do better I fear custom software which is beyond what I can discuss here. That is, image processing. My thought is to extend the shutter time by taking 2 frames and blending those for a single frame. It won't be perfect but could help. Figure it may take a programmer to make it happen.

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(NT) Bad typo in title. Sorry.
by R. Proffitt Forum moderator / May 17, 2014 10:07 PM PDT
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