10D + 580EX AF assist problem

[heizenberg]

Hi,

 

I just got my 580EX yesterday... my first external flash unit and I've already

run into my first problem. I went over both the 10D and the 580EX manuals but

didn't find any 'cure'.

 

The problem is that the red AF assist grid pattern that the flash projects in

low light/low contrast to help in auto focus seems to work fine in all the auto

modes. However in the manual modes (Tv, Av, M, A-DEP), the AF assist just

doesn't seem to work and the lens continually hunts. I've tried as many

combinations of the Custom Functions both on the flash (C. Fn. 12 - AF assist

on/off) and on the 10D (C. Fn. 05 - AF-assist beam, Flash firing). The flash

fires fine in both modes, but the AF-assist consistently does NOT fire in the

manual modes.

 

The first obvious answer is that I'm doing something wrong. I'll take the camera

and flash to a nearby Wolf camera and try a different 580EX on the camera to

check if it works and if I can eliminate either the 10D or the 580EX from the

equation.

 

Thanks,

Ananda

[pete w]

Hi Ananda, Check the camera's Custom Function settings to make sure the AF assist is set

to emit. Take Care, Pete

[heizenberg]

Hi Pete/Marlene,

I already did. It's set to Emit/Fire.

Thanks,

Ananda

[PuppyDigs]

AF assist doesn't work in AI servo. Could that be your problem?

[heizenberg]

Aha! I knew there would be an answer in the forum! I kept searching the manual for AF-assist and didn't find any reference to the one-shot, AI and Servo. But you're right! That was it. I switched to AI and it now works like a charm. Thanks!