Pixel binning/burst rate/ Quality

[jaomul]

Hi all,

I have read this term pixel binning and I am wondering if anyone could tell me if I am interpreting it correctly. I understand this as combining pixels when you decrease the sensors native resolution. (or does it just dump a percentage completely?)
Does this in turn mean that if you select say a medium size raw file that the quality of the final image should be of similar quality to a full size raw albeit with a decreased resolution? (or is it a lesser quality image due less light catchers?)

It seems that my cameras burst rate increases with lower size files and in situations where a half sized resolution image is more than enough, am in losing just resolution or sacrificing the image in other areas also?,
Thanks

 

[Patrice]

A preliminary search had these pages as a starting point to find the answer. I don't have a lot of time right now to do this reading to see if the answer is there, why don't you have a go and then inform the rest of us. You asked the question and I'm sorry but I don't have the time today to read this stuff for you.

CCD University
PixelBinning
Hamamatsu Learning Center: Pixel Binning
Binning
Binning
http://www.cmosis.com/assets/pdf/publications/slides-cmosis-eos-june2009.pdf
http://www.cmosis.com/assets/pdf/publications/slides-cmosis-eos-june2009.pdf

 

[jaomul]

Those links are all very scientific and maths orientated.They don't go into the quality of the image afterwards. I tried to find info on this before I asked but couldn't which is why I asked here. Thanks

 

[480sparky]

The sensors in your DSLR are color blind. They would normally see all colors equally and end up recording the scene in shades of gray. To make each sensor photosite "see" in color, each one has a colored filter on top of it so it records only a certain color (red, green or blue) of light.

In order to create an RGB pixel in the image, the processor combines the information from 4 adjacent sensor pixels to create a single image pixel. In this image, the data from photosites #s 1,2,5 and 6 are combined, or "pixel binned". The process is repeated for photosites # 2, 3, 6 and 7, then again for 3, 4, 7 and 8.....

 

[nmoody]

Nice! Thanks for sharing that Sparky

 

[KmH]

... the processor combines the information from 4 adjacent sensor pixels to create a single image pixel.

The luminosity recorded by image sensor pixels 1, 2, 5, and 6 is combined by the demosacing algorithm to make 4 image pixels, not just 1 image pixel, and all 4 image of those image pixels can have much different tones if they are on a high contrast edge as opposed to all 4 being part of nice smooth gradient in the sky.

The algorithm decides what color image pixel 1 needs to be based on the luminosity all 4 pixels in the Bayer Array of 2 green, 1 blue, and 1 red filters. The algorithm does the same for pixels 2, 5, and 6.

Here are some image pixels, and the part of the image they represent:

 

[jaomul]

Ok. So is a 10mp raw file from an 18mp sensor as good in quality but just a lower resolution or not? Is an accurate yes or no answer possible, or is it a not black or white type answer?

 

[o hey tyler]

This would actually make for a pretty cool abstract piece. I like the subtle variations in shade.

 

[KmH]

Ok. So is a 10mp raw file from an 18mp sensor as good in quality but just a lower resolution or not? Is an accurate yes or no answer possible, or is it a not black or white type answer?

It is indeed a 'it depends' situation.

Define 'image quality'. Which Raw processor is doing the conversion. Each uses it's own slightly different algorithms, so a Raw file converted in ACR looks a bit different from the same Raw file converted using DPP.