Canon Speedlite ST-E3-RT Mode D'emploi page 16

Turning on the Power
About Auto Power Off
To save battery power, the power will turn off automatically after 5 min.
of idle use. To turn on the transmitter again, press the camera's shutter
button halfway, or press the test flash button (charge lamp).
About the Lock Function
By setting the power switch to <a>, you can disable flash's button
and dial operations. Use this to prevent the transmitter function settings
from being accidentally changed after you set them.
If you operate a button or dial, <LOCKED> is displayed on the LCD
panel (the functions displayed above function buttons 1 to 4, such as
<=> and <@>, are not displayed).
About the LCD Panel Illumination
When a button or dial is operated, the LCD panel illuminates in green
for 12 sec. When setting a function, the illumination continues until the
setting is complete.
If the transmitter is the master unit in linked shooting, the LCD panel
illuminates in green. If the transmitter is a slave unit, it illuminates in
orange.
You cannot use the test flash while the camera's 3/1/2 timer is
operating.
The transmitter settings are stored even when the power is turned off. To
retain the settings when replacing the batteries, replace the batteries
within 1 min. of turning off the power switch and removing the batteries.
You can fire a test flash even when the power switch is set to the
<a> position. Also, when a button or dial is operated, the LCD panel
illuminates.
You can set a beep to sound when the slave unit is fully charged
(C.Fn-20/p.57).
Auto power off can be disabled (C.Fn-01/p.56).
You can change the duration of the LCD panel illumination (C.Fn-22/p.57).
You can change the color of the LCD panel illumination (P.Fn-03, 04/p.58).
14