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Strobing issue in the 7D movie

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Nick 2746
Strobing issue in the 7D movie
on Dec 21, 2009 at 9:49:45 am

I am having problems with slight strobing when people walk past the camera, like in a street scene. I hadn't noticed this issue when shooting and editing with Sony Z1. I am shooting with Canon 7D 1920x1080 in PAL, 25 fps at 1/50th shutter speed. I transcode it with ProRes using MPG Streamclip at 1920x1080 (unscaled), no interlacing. I then import it in FCP with the Codec set to Apple ProRes and edit it, Field Dominance set to none. Sequence settings: 1920x1080/HDTV 1080i. After editing the Sequence is exported to Compressor for DVD burning. I get the same problem if I downconvert the fianl movie using MPG Streamclip to 1080x576 (16:9). I would be grateful for any advice to how to overcome this strobing issue.
Thanks in advance.


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Nick 2746
Re: Strobing issue in the 7D movie
on Dec 21, 2009 at 10:05:01 am

May be it's to do with shooting Progressive. In 50th of a second people closer to the camera have moved on a fair bit in their position in the frame. One might not get this issue if shooting interlaced video in the same way. Am I right?



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Mike Cohen
Re: Strobing issue in the 7D movie
on Dec 23, 2009 at 3:16:08 am

That's what I would say. Shooting progressive and then exporting to interlaced could cause problems. Stick with progressive. Let the DVD player deal with interlacing should the end user have an analog tv.

Mike Cohen


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Jonathan Ziegler
Re: Strobing issue in the 7D movie
on Dec 23, 2009 at 5:18:12 pm

Yes, it's basically that a DSLR is still scanning the sensor from top to bottom (or bottom to top, I don't remember which) - the result is a distortion of objects coming in from the side because one part moves there before the sensor is done scanning - making for a diagonal, distorted look OR you will see some strobing. I try fixing by using a faster shutter and/or a wider lens. Boris has a plug-in that will fix the distortion, too.

Jonathan Ziegler
http://www.electrictiger.com/
520-360-8293


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George Cozmenco
Re: Lighting problem in the film 7d
on Jan 11, 2010 at 4:43:38 pm

We tasted the 7D in low light conditions & a 24p behaves well :)

I put a video here,Tiratto Dublin:

http://www.Or video.Eu /

George


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George Cozmenco
Re: Lighting problem in the film 7d
on Jul 4, 2012 at 7:03:16 pm

this is a web translation of a message written in italian, please remove this thread completely, many thanks.


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