C.fn Iii: Autofocus/Drive - Canon EOS 650D Instruction Manual

3 Custom Function SettingsN

C.Fn III: Autofocus/Drive

C.Fn-4
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 If an external Speedlite is attached, it will emit the AF-assist beam when 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. necessary. The camera's built-in flash will not fire the AF-assist beam. 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 Among external Speedlites, only those which have an infrared AF-assist Among external Speedlites, only those which have an infrared AF-assist
beam will be able to emit the beam. This prevents any Speedlite which beam will be able to emit the beam. This prevents any Speedlite which 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 uses a series of intermittent flashes (like the built-in flash) from firing the 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 With an EX-series Speedlite equipped with an LED light, the LED light With an EX-series Speedlite equipped with an LED light, the LED light
will not automatically turn on for AF-assist. will not automatically turn on for AF-assist. will not automatically turn on for AF-assist.
If the external Speedlite's [ If the external Speedlite's 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 ], the Speedlite will not emit the AF-assist beam even if the ], the Speedlite will not emit the AF-assist beam even if the
camera's C.Fn-4 is set to 0, 2, or 3. camera's C.Fn-4 is set to 0, 2, or 3. camera's C.Fn-4 is set to 0, 2, or 3.
C.Fn-5
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.
296
AF-assist beam firing
[AF-assist beam firing AF-assist beam firing
Mirror lockup