3Custom Function SettingsN

C.Fn III: Autofocus/DriveC.Fn-4 AF-assist beam firing

The settings to specify whether or not the AF-assist beam is emitted by the camera’s built-in flash or by an external, EOS-dedicated Speedlite can be set.

0:Enable

If necessary, the AF-assist beam will be emitted by the built-in flash or external Speedlite.

1:Disable

The AF-assist beam is not emitted.

2:Enable external flash only

If an external Speedlite is attached, it will emit the AF-assist beam when necessary. The camera’s built-in flash will not fire the AF-assist beam.

3:IR AF assist beam only

Among external Speedlites, only those which have an infrared AF-assist beam will be able to emit the beam. This prevents any Speedlite which uses a series of intermittent flashes (like the built-in flash) from firing the AF-assist beam.

With an EX-series Speedlite equipped with an LED light, the LED light will not automatically turn on for AF-assist.

If the external Speedlite’s [AF-assist beam firing] Custom Function is set to [Disabled], the Speedlite will not emit the AF-assist beam even if the camera’s C.Fn-4 is set to 0, 2, or 3.

C.Fn-5 Mirror lockup

0:Disable

1:Enable

Prevents mechanical vibrations in the camera caused by the reflex mirror action (mirror shock), which can disturb shooting with super telephoto lenses or close-up (macro) shooting. See page 140 for the mirror lockup procedure.

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