Canon EOS 7D Mark II Instruction Manual page 277

Fully Automatic Shooting with One External Speedlite and
the Built-in Flash
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2
If the built-in flash does not fire sufficient light, set a higher ISO speed
(p.154).
The 8:1 to 1:1 flash ratio is equivalent to 3:1 to 1:1 stops (1/2-stop
increments).
Using Wireless FlashN
This is fully automatic wireless flash
shooting with one external Speedlite and
the built-in flash.
You can change the flash ratio between
the external Speedlite and built-in flash
to adjust how the shadows look on the
subject.
Set [Wireless func.] to [0:3].
Set the desired flash ratio and
take the picture.
Select [1:2] and set the flash ratio
within 8:1 to 1:1. Setting a flash ratio
to the right of 1:1 is not possible.
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