teh wrote:Check the bmcuser forum. I believe this topic has been discussed there. I am really not an expert on this but as far as I know it is important to understand that "Raw resolution" isn't the same as debayered resolution.
From the camera's 2.5k Raw image you can get a real 1920x1080 resolution 422 image. It's not possible to debayer 2.5k into 2.5k pro res 422. You actually need the extra resolution for the color information.
I believe this is the same reason why you can't get a 4444 image out of the camera.
I might be mistaken here but I believe the bottom line is: It's not possible.
On the other hand I would like to ask, what do you need 2k oder 2.5k for? I believe for most of our distribution we will downres to 1080, 720 or any way. If it's about a slight cropping then just crop the 1080 image a up res afterwards. I have seen a lot of people doing this with alexa 1080 footage e.g.
Chroma sub-sampling and bayer resolutions are completely different things and mixing up the two can lead to a long and detailed argument online (seen it happen sooo many times
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You can indeed get a full image without any chroma-subsampling with the bmcc in raw mode. Having enough photosites in order to have x1 R x1 G x1 B pixel when rescaled down to a set resolution is a different issue to sub-sampling the chroma channels. The two should not be interchanged or compared. They are in some ways related to the overall image at the end of the process - but its important to distinguish the two.
Chroma sub-sampling is taking information away for compression/data rate purposes. Oversampling a bayer sensor in order to have one of each colour per pixel is different. It is true that the BMCC does not have a high enough resolution sensor to have 1 RGB photosite per HD resolution pixel - but depending on how the bayer data is processed and debayered makes a big difference on the actual final quality of the colour channels.
In answer to the other questions regarding Cineform Raw:
I use a PC, ive not had any problems with meta data throughout the process....yet. If you do have problems, contact cineform, their support staff are great.