Is R3D 4:4:4 or 4:2:2?

[Evin Grant]

Debayering has also become much more sophisticated in the recent past so just because a sensor is mathematically 50% green, 25% Blue and 25% Red does not mean that this is all the usable resolution it has for each channel. We know that with a 5K Epic file we can extract 4K+ worth of measurable luma resolution so even if we use the old 4K luma numbers for the chroma we'd still have 3.6-3.8K worth of chroma resolution. Despite it's irrelevance my guess is that would equate to about 4:3.5:3.5, much closer to 4:4:4 than 4:2:2.

[Martin Stevens]

Debayering has also become much more sophisticated in the recent past so just because a sensor is mathematically 50% green, 25% Blue and 25% Red does not mean that this is all the usable resolution it has for each channel. We know that with a 5K Epic file we can extract 4K+ worth of measurable luma resolution so even if we use the old 4K luma numbers for the chroma we'd still have 3.6-3.8K worth of chroma resolution. Despite it's irrelevance my guess is that would equate to about 4:3.5:3.5, much closer to 4:4:4 than 4:2:2.

This math makes the most "real" sense to me.

Thanks Evin.

[Graeme Nattress]

I think you didn't pay attention to what Graeme said. Your statement doesn't compute.

Correct. That is an over-simplistic answer to a fundamentally complex (and more interesting) question. I prefer the more reasonable response I gave above.

Graeme

[Tom.Wong]

the questions shouldn't be whether it's 444 or 422. these numbers don't apply to rgb raw. the real question is, what is the full color gamut that comes off the Epic sensor. RED never released any charts on that on how wide the range of color Epic produces. RAW is RAW, but depending on the technology that goes behind it, every camera produces a different range in color gamut.

[Graeme Nattress]

Sensor colour gamuts are not precisely defined in the way that monitors are with their distinct primaries. Our cameras all have similarly wide gamuts, and all colour filter array cameras pretty much use the same dyes on the sensor anyway.

Where we continually try to work, improve and learn is raw development, with a strong sense of digital cinema aesthetic rather than a video aesthetic in mind. In the process of working on REDColor3 I've learned a significant number of new nuances which will influence future development.

Graeme

[Jonas Rejman]

Thanks for the lectures, Graeme. Always an informative read.


p.s.

And why does Graeme has time to post here, instead of finishing REDColor3?
Is it done yet? (nag nag nag nag nag)

[Graeme Nattress]

Gosh I hope I wasn't lecturing :-)

Graeme

[Martin Stevens]

How about.....Graeme is a Genius!

I can hardly wait to experience the cinema oriented RedGamma3 etc.?

[Christian Jadot]

I love these threads! The one I have to read a couple times to get it to sink in.

Thanks for the detailed explinations again Graeme.

[Uli Plank]

More food for thought, just to show how complex things are: RED is filtering luminance (with the OLPF) quite conservatively to avoid any aliasing, but decided not to filter out all chroma aliasing, since that would soften the image too much. That's why there has been an option for chroma filtering in all the post software RED gave us. So, what about the rare cases of chroma moiré, i.e. false detail? Would you be better off having 422 or 444? I believe that depends so much on the way downsampling is done, that it's quite difficult to give a general answer.

BTW, the RED cameras have far less chroma aliasing than a Sony F3…