DSLR Video - how does it work? (techincal)

Started Oct 20, 2009 | Discussions thread
tko Forum Pro • Posts: 13,383
uhmm

Let me step in with my guess.

First of, 10 FPS is a mirror and bandwidth limitation, not a sensor limitation. I believe the sensors are read out at the full video rate, and don't skip anything.

Secondly, no one can do true pixel binning at a video rate right now. They are working on it, and Canon has a short note on it, but it is ready yet. Even for SRAW I don't think they do true binning.

I believe the video processor simply skips rows and column as required. That would mean for noise purposes you are not dealing with a full size, sensor, the effective sensor size probably isn't that much larger than a true video camera.

Maybe my math is too simple but 1080p is 1080 lines, a 7D does 3456, so only 33% of the sensor is used. That would make a 1" sensor into a 1/3" sensor for noise purposes. A good video recorder can have 3 1/3" RGB sensors so at first glance that video recorder should have better noise characteristics.

http://gizmodo.com/5051331/giz-explains-why-dslrs-are-finally-shooting-video

So, it seems to me that all pixels at read, and the video conversion just throws away what it can't use.

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