If you want some light reading, I've written a couple of web pages documenting the Nikon Concentric Rings problems:
http://www.markshelley.co.uk/Astronomy/NikonConcentricRings/nikon_lossy_compression.html
http://www.markshelley.co.uk/Astronomy/NikonConcentricRings/nikon_hardcoded_correction.html
With the help of the astro-community sending me raw files I've been able to prove that Nikon has been doing this for at least the last 10 years! However, I don't expect this to go viral in the same way that my discovery and analysis of the Sony "star eater" went viral.
I don't recommend Nikon cameras for astrophotography. In fact, I don't recommend Sony either and some Fujifilm models also have dodgy rings. My advice for DSLR/Mirrorless astrophotography is to stick with Canon.
Mark
Wow Mark, that is some paper. Well done.
Have you communicated with Nikon about it?
Carole
Quote from: CaroleWow Mark, that is some paper. Well done.
Have you communicated with Nikon about it?
Yes we'll contact Nikon but I'm not optimistic. Sony has been applying a far worse colour shading correction for years and they don't care. One Sony example I saw was a daylight wedding image from wedding photographer who was definitely not amused by concentric coloured polygons in his image!
Mark
Yet Canon does not apply any of this. Long time since l used a DSLR DS images. But l only ever used Canon as you advised me in the first place.
Carole