I am using ASI cameras that support a 12-bit ADC. When I use the default Ekos/INDI settings I notice that the INDI Control Panel shows that the 8-bit Raw Format is selected. This then results in my captured images being saved as only 8-bit FITS files i.e. stats show a maximum value of 255. Reading the docs, I picked up that 8 and 16 bit FITS are supported and to recover the extra 4 bits I will need to use the 16-bit format. When I then view the FITS stats, am I correct in saying that the 12-bit values are scaled up to fit a 16 bit values i.e. 0-4096 -> 0-65535? Also, when I exit and re-run the software the Format always defaults back to 8-bits. Is there a way to force the setting to stay at 16-bit?
As you can see Jasem has made sure that in future versions of INDI the default bit depth is set to 16 bits. Please read the rest of the comments in the thread as well.
I don't believe my statement was incorrect. For reference I found this explanation. engineering.stackexchange.com/questions/...ustified-adc-results
If I understand correctly, Left-justified would be read as 0x123456789ABC0000 (would be binary in reality). Example being representative of 12 bits of information in a 16 bit register. The extra bits being zeros, as I said.
Might be a semantic disagreement
Yes, the result from the ADC will be padded with zeros. Padded on the right side. So the max value from the ADC (4095 = '111111111111') will be placed in 16bit as '1111111111110000'. Expressed in 16-bit, this is a four-fold bit shift left of the value 4095, which corresponds to a multiplication with 16. I'd well call that 'scaling'.
Upshot is, the data you get from ASIs is 0->65520, not 0->4095.