Marcos Montenegro
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Phil:
This is Canon's official reason why they went 8-bit instead of 10-bit:
The video components within the EOS C300 camera are processed at 13-bit for Green and 12-bit each for Red and Blue. This allows excellent nonlinear processing of the video that ensures a superb tonal reproduction over the nominally exposed range (that is, from reference white down to capped black level). A contrast ration in excess of 500:1 is achieved. In addition this bit depth has sufficient overhead to handle overexposed signals. When the camera is set to 850 ISO and the Gamma transfer function is switched to Canon-Log an 800% overexposure is achieved – which translates to the camera being able to capture an Exposure Latitude of 12 f-stops.
The Red, Green, and Blue video signals are subsequently matriced to formulate the Luma video component and the two color difference signals according to the 4:2:2 coding structure preparatory to being compressed according to the MPEG-2 422Profile@High Level international standard. This standard firmly stipulates 8-bit. Accordingly, the fully processed 4:2:2 video components are transformed to an 8-bit depth before being sent to the compression engine. This process loses very little of the careful management of the nonlinear transfer function performed (as described above) at the higher bit depths.
The serial representation of the uncompressed 4:2:2 component set is structured from the parallel 8-bit component set and is fed to the camera's HD SDI interface allowing parallel outboard recording to be implemented if desired.
This is Canon's official reason why they went 8-bit instead of 10-bit:
The video components within the EOS C300 camera are processed at 13-bit for Green and 12-bit each for Red and Blue. This allows excellent nonlinear processing of the video that ensures a superb tonal reproduction over the nominally exposed range (that is, from reference white down to capped black level). A contrast ration in excess of 500:1 is achieved. In addition this bit depth has sufficient overhead to handle overexposed signals. When the camera is set to 850 ISO and the Gamma transfer function is switched to Canon-Log an 800% overexposure is achieved – which translates to the camera being able to capture an Exposure Latitude of 12 f-stops.
The Red, Green, and Blue video signals are subsequently matriced to formulate the Luma video component and the two color difference signals according to the 4:2:2 coding structure preparatory to being compressed according to the MPEG-2 422Profile@High Level international standard. This standard firmly stipulates 8-bit. Accordingly, the fully processed 4:2:2 video components are transformed to an 8-bit depth before being sent to the compression engine. This process loses very little of the careful management of the nonlinear transfer function performed (as described above) at the higher bit depths.
The serial representation of the uncompressed 4:2:2 component set is structured from the parallel 8-bit component set and is fed to the camera's HD SDI interface allowing parallel outboard recording to be implemented if desired.
