Canon EOS 80D - Manual (Page 173)

171
D Using the Built-in Flash
Effective Range of Built-in Flash (Approx. in meters / feet)
* When a high ISO speed is set and focusing distance is long, appropriate
exposure may not be obtained depending on the subject conditions, etc.
ISO Speed
(p. 135 )
EF-S18-135mm f/3.5-5.6 IS USM
Wide Angle Telephoto
f/3.5 f/5.6
ISO 100 1 - 3.4 / 3.3 - 11.2 1 - 2.1 / 3.3 - 6.9
ISO 400 1 - 6.9 / 3.3 - 22.6 1 - 4.3 / 3.3 - 14.1
ISO 1600 1.7 - 13.7 / 5.6 - 44.9 1.1 - 8.6 / 3.6 - 28.2
ISO 6400 3.4 - 27.4 / 11.2 - 89.9 2.1 - 17.1 / 6.9 - 56.1
 Flash cannot be used with movie shooting. It will not fire.
 AEB cannot be used with flash.
 Detach any lens hood when shooting with the built-in flash.
 If a lens hood is attached or if the subject is too close, the built-in flash
will be obstructed and the bottom of the captured image may look dark.
 Do not perform flash photography when the built-in flash is held down
with your finger or not fully raised for some other reason.
If you use a super telephoto lens or large-aperture lens and the bottom of
the picture looks dark, using an external Speedlite (sold separately) is
recommended.