What exactly does a debayer do?

[Timothy Carr]

Sorry if i put this in the wrong section, and its a stupid question, but nobody can answer me. What exactly is it, and how does it effect footage?

 

[Bob Gundu]

Fair question. Here is a great article on the subject:

http://www.stark-labs.com/craig/articles/assets/Debayering_API.pdf

 

[Timothy Carr]

so its pretty much just "undoing" what the camera does to get a color image?

 

[Yoav Yerushalmi]

I wouldn't call it 'undoing'. It's dealing with the physical limitations of the technology. The 'sensor technology' that the scarlet uses is only able to see brightness, but not color. So they have to put filters on there and have one sensor dedicated to each of three colors, and they arrange them in a 'bayer' array.

So the camera didn't do anything to the image. It's simply unable to get the full color full resolution information, so it has to extrapolate it from what it *can* get -- ergo debayering.

There *are* sensor technologies that can get full color information at every pixel. We have 3CMOS systems where there are three sensors and the light is split by color to each. There are also foveon sensors that can actually read the full three colors at every pixel... But Red is using a classic bayer CMOS...

 

[Yoav Yerushalmi]

Oh as to how it affects footage: Because you're not reading the full color information at every pixel, and instead using math to guess, you can sometimes get some very 'odd' things. It completely depends on how you extrapolate the full colors at every pixel. One common example:

if you have thin strips of white/black, you end up reading 'full brightness' at some pixels, and 'full dark' at others. If they happen to line up such that the red pixels are all reading full, and the blue and green are not, you end up seeing what looks like a 'red' image instead of what it really should be...

 

[James Fleming]

Interesting article. Thanks Bob.

 

[Cid J Salcido Uyarra]

I'll take a 4k Foveon Sensor over a 6K Dragon, Better blacks and less Moire helps create a sharper image. Black and White stills look amazing!

I guess if your shooting 6K and finishing in 4K you can get similar results?

of all camera companies it's property of Sigma LOL

 

[Les Dittert]

Foveon has trouble with saturation and clean colors due to the poor color discrimination of the depth based tech.

I strongly believe Red will be revamping their 'demosaic' this summer due to market factors.

 

[Jaakko Rinne]

I'll take a 4k Foveon Sensor over a 6K Dragon, Better blacks and less Moire helps create a sharper image. Black and White stills look amazing!

Seeing how Foveon sensors are noisy as hell and have really bad sensitivity, I'd pass. A 5K bayer sensor resolves to 4K, 6K would resolve to 4.8K.

 

[Cid J Salcido Uyarra]

I'm really curious to see how well Dragon is gonna hold up.

Never used a Sigma camera with Foveon technology so I couldn't give an opinion with user experience. I did read that the ISO range varies in quality some settings are better than others due to the algorithms.

Did not know 5K bayer sensor resolves to 4K that's good juice, too bad Scarlet only does 12fps.