Canon 550 EX - Manual (Page 22)

12. AF-Assist Beam
In low-light or low-contrast situations, the
Speedlite emits the AF-assist beam
automatically to assist autofocusing. The
AF-assist beam is compatible with the
AF of all EOS cameras. The AF-assist
beam is effective with 28mm and longer
lenses. Its effective range in darkness is
indicated in the table below. See page
123 for details on when the AF-assist
beam is emitted.
When Speedlite 550EX is attached to an
EOS camera equipped with a <
>
button, pressing the < > button
resets the Speedlite’s settings (except
the Custom Functions) to its default
settings
22
Position Effective Range
Center Approx. 0.6 - 10 m / 2 - 33 ft.
Periphery Approx. 0.6 - 5 m / 2 - 16.4 ft.
Automatic Reversion to Default Settings
As a Normal
Speedlite
As a
Wireless
Master
Unit
E-TTL autoflash*
(All related settings are canceled.)
Auto zoom
E-TTL autoflash*
(All related settings are canceled.)
Master flash ON
No flash ratio setting
* With the EOS-1N and EOS-1, TTL autoflash takes
effect.
02. F073-E (9~) 02.4.1 2:08 PM Page 22