Canon Speedlite Transmitter ST-E3-RT Instruction Manual - Page 29

Using Fully Automatic Wireless Flash Flash exposure compensation and other settings set on the transmitter (master unit) will also be automatically set in the flash (slave unit). You do not need to operate the slave unit. f Flash Exposure Compensation In the same way as normal exposure compensation, you can set exposure compensation for flash. The flash exposure compensation amount can be set up to ±3 stops in 1/3-stop increments. 1 Display . Press function button 4 to display . 2 Press the button. Press function button 2 . X is displayed and the flash exposure compensation amount is highlighted. 3 Set the flash exposure compensation amount. Turn to set the flash exposure compensation amount, and press . X The flash exposure compensation amount is set. "0.3" indicates 1/3 stops and "0.7" indicates 2/3 stops. To cancel flash exposure compensation, return the compensation amount to "±0". Generally, set an increased exposure compensation for bright subjects and set a decreased exposure compensation for dark subjects. If the camera's exposure compensation is set to 1/2-stop increments, flash exposure compensation will be up to ±3 stops in 1/2-stop increments. When the flash exposure compensation is set on both the transmitter and the camera, the transmitter setting is given priority. The flash exposure compensation amount can be set directly with without pressing the button (C.Fn-13/p.57). 27