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 (recording movies)
[Fn2] button (bright frame simulation)
[Fn3] button (metering)
[Fn4] button (film simulation)
[Fn5] button (white balance)
[Fn6] button (AF mode)
Center of rear command dial (Focus check)