as those with an FS7 will probably know, Sony announced the FX9 at IBC 2019. Certainly in Europe, they are doing tours showing off the new kit and it looks great. Even with pre-production firmware. The auto-focus was as good as they announced and the color looked good. although it wasn't in the best light.
I was kind of dreading it because the switch to full-frame lenses seemed to imply that you need to replace your existing lenses. However as the A7S series are full frame you may already have some. What you all probably know but I didn't until yesterday was that the SELP28135G kit lens is Full Frame! It felt like I had a big discount, at least to start with!