1Ds3, using a speedlite to assist in autofocus

On my 5D2 you can set the speedlite to emit the IR beam in order to assist the autofocus (without firing the flash). It needs to be done in the cameras menu but I can't find it on my 1Ds3.

Does it exist or is that for newer cameras only?

Thanks!
Gel

The flash assist beam should be automatic, but here's a possible clue: it only works in One Shot AF or AI Focus AF, so if you're in AI Servo AF it won't work. So...

I know it use to work on mine with 580EX II, but now I can't figure out how to make it work again? Not sure if I changed something on the flash or in my camera body, but it definitely use to work. If you can get yours to work again please post here what you did.

Take Care,
Cheers, Patrick

Gel wrote in post #10857881
It needs to be done in the cameras menu but I can't find it on my 1Ds3.

All flash option are possible at flash interface/screen, i believe.

This function is not allowed at 430EX II. only 580EX II.

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