Debayer Pattern Canon 450D

[Scooot]

Hi, could someone please tell me what is the correct debayer pattern to use to debayer a Cr2 image taken with a canon 450D.

[Alejandro Tombolini]

Hi Richard, it is RGGB.

Saludos, Alejandro

[Scooot]

Thank you Alejandro, I have always used RGGB to date but I was never that happy with the colours, especially with my moon images, so I've been experimenting with a day light image and it seems as if that might be wrong which is why I wanted to check.

Here's three below. The first is a fully processed image showing more or less the correct colours. The second is debayered using RGGB and auto stretched. The third is debayered with GBGR with the same auto stretch. They obviously need further processing but the third using GBGR seems to be the closest match, at least the leaves are green.

So it seems as if GBGR is better but I wanted the feedback from others because its likely I'm not doing something correctly.

When loading them into pixinsight I used pure raw camera white balance

[Alejandro Tombolini]

Hi Richard, I checked and definitely it seem incorrect GBGR with my 450D

Saludos, Alejandro.

 

[Scooot]

Thanks Alejandro,
It’s a bit of a mystery. If I change the DSLR settings in format explorer to de-bayer RGB it will open with correct colours. But if I open in pure raw and debayer nothing is very good, but RGGB is very poor. Oh well.

[Scooot]

Alejandro, within the 450D camera settings there’s a choice between sRGB and Adobe RGB. Mine is set to sRGB, is yours? I’m wondering if this would make a difference?

[Scooot]

I've attached a linear greyscale of it. I wonder if anyone else wants to try to debayer it to see if they get the same results.

[dld]

Hello,

According to http://lclevy.free.fr/cr2/, Section 4,

The 450d, like all Canon EOS cameras, and the G9, have a RGGB CFA.

Do you crop before you manually debayer? If you do, then it is not easy to assign each pixel to the correct channel. The Debayer Process with the auto pattern setting enabled, does not work in such cases.

Can you upload (Google Drive, Dropbox or elsewhere) an unprocessed daylight raw file?

[Scooot]

Thanks Dld,

No I didn't crop before the debayer process, I did rotate it though with geometry.

Heres a link
https://www.dropbox.com/s/jixomrjoo26g21z/IMG_1793%20RAW.xisf?dl=0

[Scooot]

Ah, solved thanks Dld.

If I don’t rotate it and leave it totally untouched before debayer it does It correctly.

I knew someone would know 😀😀

[sharkmelley]

Heres a link
https://www.dropbox.com/s/jixomrjoo26g21z/IMG_1793%20RAW.xisf?dl=0

RGGB works fine for this image.
Definitely don't rotate it before debayering. 

Mark

[dld]

Haha yes, that's it! Now your beehive looks normal again If for some odd reason you wish to debayer the rotated image, the correct pattern is GBRG 8)

[Scooot]

Thanks everyone for the help, really pleased I’ve learnt this, it was a good excercise to find out and got there in the end.