Canon EOS M Basic Instruction Manual page 324

3 Setting Speedlite FunctionsN
Setting the Speedlite Custom Functions
The Custom Functions displayed under [Flash C.Fn settings] will vary
depending on the Speedlite model.
Clear the Settings
224
Display the Custom Function.
1
With the camera ready to shoot with
an external Speedlite, select [Flash
C.Fn settings], then press <Q/
0>.
Set the Custom Function.
2
Either tap [Y]/[Z] or press the
<YA>/<ZO> button to select the
number and set the function. The
procedure is the same as setting the
camera's Custom Functions (p.282).
Select [Clear settings].
1
Under the [A1: External Speedlite
control] tab, select [Clear settings],
then press <Q/0>.
Select the settings to be cleared.
2
Select [Clear flash settings] or
[Clear all Speedlite C.Fn's], then
press <Q/0>.
When you select [OK], the respective
flash settings will be cleared.