Canon EOS Rebel T6i EF-S 18-55mm IS STM Lens Kit Instruction Manual - Page 173

3 Setting the FlashK With the built-in flash or an EX-series, external Speedlite compatible with flash function settings, you can use the camera's menu to set flash functions and the external Speedlite's Custom Functions. If you use an external Speedlite, attach the Speedlite to the camera and turn on the Speedlite before setting the flash functions. For details on the external Speedlite's flash functions, refer to the Speedlite's instruction manual. Select [Flash control].  Under the [z1] tab, select [Flash control], then press .  The Flash control screen will appear. [Flash firing] [E-TTL II meter.]  Normally, set this to [Enable].  If [Disable] is set, neither the built- in flash nor the external Speedlite will fire. This is useful when you want to use only the flash's AF-assist beam.  For normal flash exposures, set this to [Evaluative].  [Average] is for advanced users. As with an external Speedlite, the metering area is averaged. Flash exposure compensation may be necessary. Even if [Flash firing] is set to [Disable], if focus is difficult to achieve in low light, the flash may still fire a series of flashes (AF-assist beam, p.103). 173