As I attempt to change muscle memory with FW 3.0, I have set up my Fn1 and 2 for different wide areas with focus on. Now I want to set up Fn3 for single point, no subject detection which I have done with f2, but it seems that unlike the other two buttons I can't set it to "focus on" and I have to push the shutter. Does anyone know of another way to do this? The "subject detection" is essential and my understanding is that the only way to turn it off immediately is recall shooting functions.