Modeling Flash - Canon Speedlite 470EX-AI Instruction Manual

Modeling Flash

When the camera's depth-of-field preview button is pressed, the flash
fires continuously for approx. 1 sec. This feature is called "modeling
flash". This is useful for checking shadows cast on the subject by the
flash light.
Modeling Flash in AI.B Full-Auto Mode
When an EOS DIGITAL camera released in or after the second half of
2017 (excluding some cameras, p.46) is used and the <X> switch is
set to <Z> full auto, the camera's depth-of-field preview button
functions as an AI.B full-auto distance measurement start button.
With this setting, you can fire a modeling flash using the test flash
button on the flash in AI.B full-auto shooting if the Custom function
C.Fn-02 is set to 1 or 2 (p.85).
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Press the depth-of-field preview
button on the camera.
The flash fires continuously for
approx. 1 sec.