Editing CR2 Astrophotography Files with DPP4 - Stars Lose Color

[MiGW]

Hello,

Shooting from very dark sky locations, using a star tracking mount, I get great results with extended duration exposures (60s, 90s, 120s, 150s), f/2.8 to f/5.6, ISO ranges from 3200-12800. 

My Rebel T5i pictures contained stars that were naturally colorful, orange, yellow, blue, white.

My 6D MkII pictures show colorful stars until DPP finishes drawing the image, then all star color becomes uniformly white. 

Is there some kind of in-camera pre-set that can be disabled? Canon Tech Support had no answers, had never encountered the issue, were unable to help troubleshooting.

Hopefully someone has a clue. 

Thx.

[John_Q]

Hello MiGW,

There are not any in-body settings that I can think of that should cause this after-effect you're describing. The only other thing I would suggest is to reset the camera to factory default settings and trying again first to verify that. You can find the reset in the yellow wrench menu tab #5 listed as Clear all camera settings. Make sure that DPP is not applying some sort of recipe to the converted images as well. 

[MiGW]

Ok, Thx.

How can I know if DPP is applying a recipe to converted images? DPP processes raw files for viewing prior to editing. During this brief span of time I can see evidence that star color was captured. When the wheel stops spinning the results appear and all stars suddenly turn white. I have taken screen shots to compare before and after differences. This is prior to any editing when camera presets like NR are applied.

I can send a set of before/after screenshots for review if that might help. Are there image file size limits?

Regards.

[jrhoffman75]

Instead of posting can you upload RAW files to a file sharing service like Dropbox or One Drive?

[MiGW]

Hello John,

I'll look into it but I can't send before and after RAW files b/c DPP does its thing when I open a file and as the image gets 'drawn' the magic happens and the final result is all I have left. 

Question: If I set NR to none in DPP will I get the same results as if I had disabled NR before shooting?

Regards,

Michael

[jrhoffman75]

You could send the RAW from a folder instead of using DPP. 

[MiGW]

Thx John_Q,

Working on it.

Regards,

Michael

[wq9nsc]

What level of noise reduction is DPP applying to your files, you can choose different default levels within the camera that will be transferred to DPP or DPP can be set to specific levels.  If extreme levels of chrominance NR are being applied, then small objects in a high ISO file can have their color info removed.

Rodger

[MiGW]

Hello Roger,

Shooting Astrophotography at ISO 12800 with exposures of 150 seconds, I pre-set in camera NR to very high levels, or adjust manually, 16-18, out of 20 possible, for Lum and 14-16 for Chrom.

I'll turn NR off and see if the problem goes away, of course there will be a circus of artifacts, but I will check for star color losses before and after DPP does its magic when I open the file.

Regards,

Michael 

[Waddizzle]

“ Is there some kind of in-camera pre-set that can be disabled? Canon Tech Support had no answers, had never encountered the issue, were unable to help troubleshooting. “

Picture Styles might do it.  I would assume that Canon Support walked you through checking those settings, though.  Are you saving images as RAW or JPG?