With an A7Riii it is saving "native" captures as a jpeg. Camera is 100% set as uncompressed RAW.Works ok with saving as a fits file
And it also works fine from the command line with gphoto2

My A7SII works fine either way so im prettry confident about how i have ekos set..
I have also set up and got working my canon camera but id really like to get RAW files to work on my A7RIII