Canon EOS 5Ds Instruction Manual page 445

Button Functions for the Quick Control and
Custom Quick Control Screens
When you press the <n>, <o>, <m>, or <S> button,
the setting screen appears and you can use <6>, <5>, <9>, or
<B> to set the functions.
Metering mode / White balance
ISO speed /
Flash exposure compensation
B Button Functions
AF operation / Drive mode
AF point selection
445