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View Full Version : Will dropping colour-sampling help with possible slow-motion?



Simon Shasha
09-24-2012, 05:56 AM
I know talking about the BMC and slow-motion has been spoken about over and over. But I was just thinking, would dropping down to 8bit colour-sampling help the camera achieve more frames-per-second? Perhaps an 8bit form of ProRes? There is a sensor, the Alexima AM41 (http://www.alexima.com) - it's a 4/3" sensor that can do up to 500FPS in 10bit, and 800FPS in 7bit. Could dropping the colour-sampling down to 8bit push more frames out of the BMC? Would you guys take the trade-off of losing colour information in exchange for more frames (hypothetically speaking)? What do you guys think?

hendrik
09-24-2012, 01:17 PM
Whether it is theoretically possible depends on sensor specs. I don't think all sensors support ADC sampling step changes. Changing the region of interest would be better I think. For example sampling 1920x1080 area would give you 48fps at the same datarate as full sensor image at 30fps.

redgamma
09-24-2012, 01:35 PM
You don't have to change the ADC readout parameters, you just chop/ignore the lower 4 bits after reading the 12 bits, and store the remaining 8 bits.
What are the sensor specs for the sensor they use. I like the idea.

Simon Shasha
09-24-2012, 02:11 PM
What are the sensor specs for the sensor they use. I like the idea.

It was suggested and thought that this might be the sensor Blackmagic has employed in the Cinema Camera, but I don't think anyone knows for sure (supposedly it is capable of 100fps @ 2.5K, and 240FPS @ 720P):

http://www.eoshd.com/content/7969/blackmagic-cinema-cameras-sensor-has-global-shutter-made-by-bae-systems

Bxl
09-25-2012, 01:49 AM
Twixtor.

redgamma
09-26-2012, 06:51 PM
Twixtor.

Twixtor works on simpler shots, sure.
But not this:
Shot of a leafless bush in frame moving against the background moving in a different direction. Twixtor fails big time.
Just a quick example. Happens with chain link fence shots, or any shot with semi sparse or transparent things, including dirty window panes, I could go on and on, but you get the idea.

Bxl
09-28-2012, 08:30 AM
I do :)