Canon Speedlite Transmitter ST-E3-RT Instruction Manual - Page 18

' Wireless Flash Shooting Using a transmitter and a Canon Speedlite compatible with radio transmission wireless shooting makes it easy to shoot with advanced wireless multiple flash lighting, in the same way as normal E-TTL II/ E-TTL autoflash shooting. The system is designed so that the settings of the transmitter attached to the camera (master) are automatically reflected on the Speedlite that is wirelessly controlled (slave). Therefore, you do not need to operate the slave unit while shooting. The basic relative positions and operating range are as shown in the figure. You can then perform wireless E-TTL II/E-TTL autoflash shooting just by setting the master unit to . Positioning and Operation Range (Example of wireless flash shooting) Autoflash Shooting Using One Slave Unit (p.24) M x Transmission distance Approx. 30 m (98.4 ft.) Position the slave unit using the mini stand supplied with the flash. Before shooting, perform a test flash (p.13) and test shooting. The transmission distance may be shorter depending on the conditions such as the positioning of slave units, the surrounding environment and weather conditions. 16