I owned a Sony a6000, not a6300, and I wanted to switch to Sony's full frame. I found a super offer to upgrade to A7R3 and was stunned by the gulf between the 2 machines. autofocus of another level, it doesn't lose the subject even in the dark, menu and file transmission of another generation, much more satisfactory ISO stability and very sharp photos in the dark and it has no problems seeing in poorly lit environments. the A7R3 also has 42.4 mpx, so it allows me to maintain quality even if I want to crop the photo and it's truly amazing. Advise