How to trigger AF-assist light on Canon Speedlites without firing the flash?

Question

Most of Canon Speedlites flashes have quite nice built-in AF-assist LED lights, which would are useful in low-light situations, even when one doesn't want to use flash in photos.

Is there any way to set the flash (or camera) to fire only AF-assist, and not the flash itself? Only way I know is to prefocus and then turn off the flash, which is not very practical.

Asked by che

Answer

Disable the flash in the camera settings. It still uses the AF-assist beam, but it will not fire the flash.

The setting is in different places depending on the camera, for example:

EOS 5D:
Menu > Custom Functions > 07

EOS 5D mk II:
Menu > Tools 3 > External Speedlite control > Flash function settings > Flash firing

EOS 550D / Rebel T2i / Kiss X4: Menu > Camera 1 > Flash control > Flash firing (it also works for built-in flash)

Answered by Guffa

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