Astrophotography Stacking FITS with 12-Bit Sensor

[barnold84]

Hi,

I am using Affinity Photo extensively for my Deep Sky Astrophotography workflow. I have a new camera that has a bit depth of 12. The FITS files created aren't scaling the 12 bit to 16 bits, i.e., the maximum brightness value is 4095 and never 65535.

How is the Astrophotography Stacking tool processing these files? 

For comparison: in Deep Sky Stacker, I need to define a scaling factor of 16 so that the very dark images are lighter and stars being correctly identified.

Thanks in advance!

Björn

[NotMyFault]

Hi Björn,

not an expert in astro photography, only interested.

Can you simply try out

1. unmodified images
2. modified images, using a levels adjustment or procedural text filter to scale up the values (may use a macro and batch processing to automate process)

and compare both results?

Regards,

Timo

[barnold84]

Hi Timo,

Thank you for the tip. It appears to me that Affinity returns an unscaled image after stacking. I usually can use the levels adjustment and reduce the white point to 6,25% (1/16) without clipping anything. Nevertheless, Affinity seems to be capable of aligning the images anyways, despite the fact that the stars are very dim due to the 12 Bit.

Best,

Björn