I just purchased the Canon Speedlite 430EX II and for the life of me I can't get the AF Assist light to come on! I shoot in manual on my 5D Mark II, and I have set the flash on ETTL. The guide says the AF assist light is supposed to come on when it senses that it's too dark, but it doesn't. I have checked the custom functions and I have made sure that the AF assist function was enabled.

Am I doing something wrong? Is there some check that I can do to be sure that the flash is properly working?


1 Answer 1


I found out why! It won't fire in AI SERVO mode, and that's the mode that I tend to keep on. Why wouldn't the guide tell us that?! Oh well. Issues fixed. =)

  • \$\begingroup\$ Make sure you select this answer \$\endgroup\$
    – camflan
    Sep 11, 2012 at 14:11
  • \$\begingroup\$ I confirm this behavior with Canon 70D and YN565EX II external flash. No AF-Assist light in AI Servo mode. It does come on in One-Shot or AI Focus modes. \$\endgroup\$
    – Jamie Cox
    Oct 29, 2017 at 17:01

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