Canon RAW .CR2 file loads show up EXTREMELY dark

[astrospotter]

PixInsight rocks and I love it for fit files and astrophotography BUT Canon RAW images have always been far too painful to load properly.

For years now since I think PI 1.6 and now I'm on 1.8 but always I have seen Canon RAW files from earlier D40 and then last few years 7D load up and be very very dark to a frankly totally unacceptable level.  There MUST be some setting that needs a tweek but I have no idea where PixInsight does that.

These same pictures load into PhotoLine and show sky areas are perhaps around 75 to 80 percent and the picture loaded from CR2 looks fine on camera preview and in PhotoLine and Gimp and the jpeg looks wonderful in normal viewers like IrfanView and so on.

As an example the picture showing sky at about 80% full scale in PhotoLine shows in PixInsight about 0.3 full scale so whole picture is VERY dark.

SO ...   is PixInsight somehow thinking the bits are all 16 bit or something so a fairly full scale value looks really dark and of course a 0.2 range pixel is for all practical purposes black in the PixInsight view.

Does anybody load Canon RAW images and have them look like they do on the camera preview or other program out there?  If so HOW do I do that?

Thanks for any comments,
Mark Johnston

[pfile]

it's normal - all the programs you are describing stretch the data, because they are for terrestrial imaging. PI does not do that because certain steps in the processing must be done on linear images. and linear images are usually almost black without some kind of stretch.

here's how to see something in your CR2s:

1) load the CR2 in "raw" mode - either CFA or RGB bayer with black point compensation turned off. you can check these settings by opening the format explorer and double clicking on "DSLR_RAW".

2) open the Debayer process. apply it to the open CR2 image

3) open the ScreenTransferFunction process. click the chain link to "unlink" the channels. make sure the debayered image is selected, and click the "nuclear" icon on the STF window. you'll see something.

rob

[astrospotter]

Thanks for the reply and I'm a bit late on the thanks due to being on a vacation till now ...  8)

I have a way to stretch it nicely and see it, I was just curious if there was a setting to do still linear stretch (not histo stretch) so that the .CR2 files when loaded would auto-linear-multiply out to be the normal brightness that the Canon jpeg file shows (like you say, like other tools for daytime tend to do).

It's all ok, I'll just keep around a default linear stretch that I make with a PI tool as an icon and it will work.  Just is a bit of something that would be nice to associate a specific user defined stretch to a particular extenstion (.CR2 in this case).

Thanks for the reply, I'll be fine as I mostly use PI for astro-photos and am very versed in all that sort of workflow.

[pfile]

oh - if you want to see your image without actually stretching it, just use the ScreenTransferFunction process. there's a keyboard shortcut as well...

also yes, PI brings the 14-bit sensor data in to a 16-bit space so everything is a little darker than 'normal' even without the stretch.

rob