Just moving from Nikon to Sony. Would like advice on what you set on your custom buttons and what you put into the fn menu. Shooting wildlife with A9ii and landscape with A7riii. Any suggestions will be appreciated so much!
Welcome to Sony. I also moved from Nikon.
On my Fn key I have
Compensation (as you only add +3 on the dial)
With that said I very rarely use the Fn to change stuff, just Compensation actually, as I have other keys (A7R4 btw) set for quick access to important settings I like to change, such as focus area on C4, a custom recall of settings for Birds in Flight on the AEL button and others accessed through the selection wheel.
I am also new to Sony but I have set C3 to In-Camera Guide, which I use a lot. The only other button that I have customised so far is C2, which I use to activate the focus magnifier in Manual focus. I have turned the magnifier off because I don't want it to come on automatically.
With recall custom settings #1 (assigned to lens button - the "slow" button in my head) I guarantee to be in A-Priority, Single shot, iso-100, AF-C, Focus Area: wide
With recall custom settings #2 (assigned to C3 button - the "turbo" button in my head) I guarantee to be in S-Priority, 1/2500s, 20-fps, iso-auto, AF-C
C4 is very usefull as a punch-in/out APSC ON/OFF to turn a 35mm into a 50mm, or a 85mm into an 135mm with a button press.
(only use that in my A1, not in my A7M3 due to lack of resolution for use in APSC)