EOS 7D Mark II: full-power flash

When using an external flashgun, you may find the flash fires at full power, possibly over-exposing the subject regardless of the flash power required. This can happen for two reasons: firstly, check the Speedlite’s Custom Function setting for “Flash metering mode” – if this is set to TTL, the flash will always fire at full power. Simply change it to ETTL to get accurate flash exposures again. The second reason is the flash model – if the Speedlite is not an EX series, but perhaps an older EZ series model, the flash will always fire at full power – switch to an EX series Speedlite to gain accurate flash metering.
EX Speedlites
Camera settings
EOS 7D Mark II