Hi All,
I wanted to experiment with my 450D to complement ASI1600mm and I noticed that stars will saturate at about 14000 ADU when shooting in FITS, same count as shooting in cr2.
I couldn't quite find an answer searching the forum: does this mean that indi/ekos, when saving to fits, will place unscaled 14-bit adu values in a 16 bit fits with the counts from 16383 to 65535 kept unused?
This seems consistent with my observations in Siril, which reads saturation at ~0.25 in 0-1.0 range.

This would mean that adu counts need to be multiplied by 4 for purposes of RN swamping calculations and Flats ADU settings.

This would also mean that if I want a flat exposed to 20000 I have to aim for 5000 as read in ekos fits viewer.

Am I right or confused?

The short answer is that, yes, it is possible. I do not recall if the indi_gphoto_ccd driver returns its data un-scaled, but some of the indi drivers return data in this manner. You are correct about the flat target if this is the case.

There is no difference in noise or signal quality. Stacking and calibration performance are not affected by scaled vs un-scaled data.

Absolutely, I was asking in order to evaluate read noise swamping and flat exposure using Kstars' reported ADU. It definitely is that way, because if I expose 3 minutes on a bright star I see it blooming, but at ~16000 adu.
Thanks for confirming!