The roles played by each of the function buttons can be selected by pressing and holding the button. The default options are shown below:
Fn1 button (Photometry)

Fn2 button (Control ring options)

Fn3 button (Film simulation)

Fn4 button (White balance)

Fn5 button (AF mode)

AEL/AFL button (Exposure/Focus lock)

Center of rear command dial (Focus check)
