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3
Custom Function Settings
N
C.Fn II -5
AF-assist beam firing
Enables or disables the AF-assist beam emitted by the built-in flash or EOS-
dedicated external Speedlite.
0: Enable
The AF-assist beam will be emitted when necessary.
1: Disable
The AF-assist beam is not emitted. This prevents the AF-assist beam from
disturbing others.
2: Enable external flash only
The AF-assist beam will be emitted when necessary only if an external
Speedlite is used. The camera’s built-in flash will not fire the AF-assist
beam.
3: IR AF assist beam only
When an external Speedlite is attached, only with infrared AFassist beam
will be emitted. This prevents the AF-assist light from firing as a burst of
small flashes.
With an EX-series Speedlite equipped with an LED light, the LED light will
not automatically turn on for AF-assist.
C.Fn II -6
Lens drive when AF impossible
If focus cannot be achieved with autofocus, you can have the camera keep
searching for the correct focus or have it stop searching.
0: Continue focus search
1: Stop focus search
If autofocus starts and the focus is far off or if focus cannot be achieved, the
lens drive stops. This prevents the lens from becoming grossly out of focus
due to focus searching.
If the external Speedlite’s [
AF-assist beam firing
] Custom Function is set
to [
Disable
], this function’s setting will be overridden and the AF-assist
beam will not be emitted by the Speedlite.
Super telephoto lenses can become grossly out of focus during continuous
focus search, taking more time to achieve focus the next time. Therefore,
setting [
1: Stop focus search
] is recommended for super telephoto lenses.