At least Sony is consistent. For years, astrophotographers – and others needing to preserve accurate, high-contrast detail points – have been frustrated by Sony’s image processing that nixes stars and other points, mistaking them for noise. With each firmware release and every camera release, some still hold out hope that the “star eating” software will be gone, or at least rendered customizable. The A7sIII is the latest in quite a long cameras that have ignored this desire.
Around the time that Sony introduced the star eater issue, the major camera manufacturers were getting more bold in “cooking” the RAW files their cameras produced. Noise reduction was one area where much of the cooking had the greatest effect on rendering. This “cooked RAW” matter had been going on for years, but previously purists shooting the 1DX and Nikon D series cameras could reasonably ignore the slowly-mounting evidence that the manufacturers weren’t giving them just photon counts.
The upshot, for now, is that if you want to take pictures of planets and nebulae, a Sony will do fine. If you’re mapping a small area of the sky, you’re going to be shooting a different brand of camera. As it is, people who own the A7sIII are not taking high-detail stills of the night sky. It is a 12 megapixel camera used primarily for video.