Demosaic/debayer Sony NEX OSC?

[Amaranthus]

I asked this over at IIS but I might get some more expert advice here

I've been using Nebulosity (Stark Labs) with success for pre-processing my monochrome CCD images captured in LRGB, but I'd like to also use it with my Sony NEX-3 DSLR (OSC). However, when I go to demosaic the RAWs (.ARW files), Nebulosity does not recognise the NEX-3/NEX-5 cameras and so switches automatically to 'manual' demosaic mode. (Bah - it's not a Canon or Nikon! )

So I'm not sure what the best settings might be for the matrix offset and color control. The standard of X=0, Y=0 and a matrix with 1s in the diagonals and 0s in other elements gives me rather unsatisfactory results - a very greenish image. Any clues? (or perhaps you know where I can look this up -- I didn't have much success in my web search). I think the Bayer pattern is RGGB for this camera.

I do wonder what dcraw might use for debayering a Sony NEX-3 (it is one of the included cameras). It's what I've been using previously when stacking with DeepSkyStacker (I pre-prepare the files using dcraw before loading them into DSS). Is there any way to back this information out of dcraw?

[Amaranthus]

So, with trial-and-error experimenting, I answered my question. The correct offset for the Sony NEX-3 was X=1, Y=1. So there you go!

I'm still not sure what Bayer pattern that corresponds too (RGGB?), given that I don't know what the default Nebulosity expects, but that's all rather immaterial to me now.

As for colour balance, I think I'll leave the diagonal as 1:1:1 and do the colour tweaking in post-processing in StarTools.

Ivo, should I be debayering with colour binning or bilinear? Somewhat unexpectedly, when I enable colour binning in Nebulosity, the resulting file is still the same dimensions/size

[admin]

As for colour balance, I think I'll leave the diagonal as 1:1:1 and do the colour tweaking in post-processing in StarTools.

Ivo, should I be debayering with colour binning or bilinear? Somewhat unexpectedly, when I enable colour binning in Nebulosity, the resulting file is still the same dimensions/size

Excellent! Yes do the color balancing in SarTools. Colour binning should give best results (since no interpolation is performed), but I agree that I'm surprised to learn that resolution hasn't changed...

[Amaranthus]

Thanks, I'll investigate further on the file size issue and report back when (if) I have an answer!