NINA TIFF and CR2 appear to be totally different images...?

[Peter Reader]

Hi all,

Recently installed the new version of NINA that permits advanced sequencing. When setting up I chose to run my Canon 1000D through the Canon driver (which saves images as CR2 format) rather than ASCOM DSLR driver (which saves images as TIFF format). Both appear to show the same preview (histogram stretched) in NINA but when viewed the saved files appear drastically different. Raw concverter is DCRAW.

Can anyone help me understand this? Are the images actually different?

 

Pinwheel Galaxy_LIGHT_240.00_0000_HFR 2.37_guide RMS 0.57 arc s.fits Pinwheel Galaxy_LIGHT_240.00_0004_HFR 2.46_guide RMS 0.66 arc s.cr2

[vlaiv]

They are the same, it is just preview that messes things up with .cr2.

Use software like FitsWork to save .cr2 file as fits file and you will get the same thing.

There are still some differences like - ASCOM fits being scaled to 12bit range while .cr2 decoded with fits works - is 16 bit. There might be color decoding going on as well.

I would personally prefer true raw data over anything else, so check what you get (you might get calibrated sRGB data or true RAW color information depending on driver used).

[Peter Reader]

2 hours ago, vlaiv said:

I would personally prefer true raw data over anything else, so check what you get (you might get calibrated sRGB data or true RAW color information depending on driver used).

Thanks, how do I test this?

My CR2 preview is very green and looks completely different to the FITS, but it's still ok to stack?

[vlaiv]

1 hour ago, Peter Reader said:

My CR2 preview is very green and looks completely different to the FITS, but it's still ok to stack?

Yes, for some reason, preview looks very strange, I get the same when I look at .cr2 with Irfanview.

It is oriented in portrait, has green cast and is only 1288 x 1936 px.

When I import it into Fitswork - it looks ok.

Maybe it would be good idea to download Fitswork (it is free software) and convert your cr2 files to fits prior to stacking if you run into any sort of issues with stacking .cr2 directly

 

[Peter Reader]

Thanks vlaiv, I'm going to stick with the ACOM DSLR driver and accept the weird scaling of the FITS files.