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Rainbow Effect When Shooting Projected Image
I have an HPX170P and I use it to live stream a speaker series to the Internet (I am with a university). These speaker series events usually include a speaker and a PowerPoint presentation that is projected onto a screen. Before each shoot I adjust AWB, Iris, focus, etc., but it never fails that once I begin the shoot I see a rainbow effect that seems to be cycling as a result of the projected image. I know this is some function of the resolution of the projector vs. the resolution I am shooting in, but I have tried many different settings and I just can’t seem to get rid of it. I am shooting (believe it or not) in 4801/40p because that is what I can push through my Wirecast software but I am seeing this image on the LCD screen on the camera, so I know it is coming from the camera with this effect. I have the Green book that came with the camera and am working through it but was wondering if anyone could help. Thanks!
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6 Replies
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[Deborah Wise] “4801/40p”????????? do you mean 480i/30p
Is the effect through the entire image or is it just the projected image in the background. If it is just the projected image you need to work on matching the scan rate of the project and camera. You can try a 1/30 shutter speed, vs the normal 1/60th. Look to see if you have too much blur at that setting, also you can adjust the syncro scan rate under the scene file settings.
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yes, I meant 480i :). Since the presentation is in the middle of the frame, the cycling occurs over the entire frame, not just the presentation. I played with the Syncro Scan and the shutter speed but I will give it another try.
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If it is the entire frame you may have an electrical hum going on, you running on AC or battery power. Are you feeding sound via XLR from a mixer?
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Wow…I never had these problems with my old DVC AG30 cameras. I am running on AC and the mic is an XLR into the camera, then from the camera via firewire to my laptop.
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without seeing the video and being at the venue all I can do is guess.
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actually, I do have a snippet of video showing the effect. It is like a laser light show :). If there is a place to send it, I would be happy to.
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