Canon EOS 30D Instruction Manual

Page of 200
169
3
 Custom Function SettingsN
C.Fn-04
Shutter/AE lock button
0: AF/AE lock
1: AE lock/AF
Convenient when you want to focus and meter separately. Press the <A> 
button to autofocus and press the shutter button halfway to attain AE lock.
2: AF/AF lock, no AE lock
In the AI Servo AF mode, you can press the <A> button to stop 
the AF operation momentarily. This prevents the AF from being 
thrown off by any obstacle passing between the camera and 
subject. The exposure is set at the moment the picture is taken.
3: AE/AF, no AE lock
This is useful for subjects which keep moving and stopping 
repeatedly. In the AI Servo AF mode, you can press the <A> button 
to start or stop the AI Servo AF operation. The exposure is set at the 
moment the picture is taken. Thus, the focusing and exposure will 
always be at the optimum point as you wait for the decisive moment.
C.Fn-05
AF-assist beam
The AF-assist beam can be emitted by the camera’s built-in flash or by 
the external, EOS-dedicated Speedlite.
0: Emits
1: Does not emit
AF-assist beam not emitted.
2: Only external flash emits
If an external, EOS-dedicated Speedlite is attached, it will emit the 
AF-assist beam when necessary. The camera’s built-in flash will 
not emit the AF-assist beam.
C.Fn-04 and C.Fn-18-0, 1, 2 (p.174) both have AF start/stop and AE lock 
functions. If you have set both these Custom Functions and you execute 
both Custom Function operations, the latter operation will not work. The only 
exception will be when AF stop is executed after AF start.
If the external, EOS-dedicated Speedlite’s [AF-assist beam] Custom 
Function is set to [Disabled], the Speedlite will not emit the AF-assist beam 
even if the camera’s C.Fn-05-0/2 is set.