XSi/450D - no focus assist beam from speedlight in manual modes

Sorry if this has been covered before, I spent over 10 minutes hunting and didn't find anything (10 minutes is about as far as I get before my patience wears out).

I've found that the autofocus assist beam on my Sigma EF-500 DG ST works in the full auto and program modes, but not in any of the manual modes (which is what I use exclusively). I think I've tried all possible menu settings even remotely related to flash function, as well as all the various shooting modes (one-shot, servo, etc.) and have come up empty. My camera firmware version is 1.0.4 if that matters.

edit to add - I just upgraded firmware to 1.1.0 and that makes no difference.

groundloop wrote in post #15655542
Sorry if this has been covered before, I spent over 10 minutes hunting and didn't find anything (10 minutes is about as far as I get before my patience wears out).

I've found that the autofocus assist beam on my Sigma EF-500 DG ST works in the full auto and program modes, but not in any of the manual modes (which is what I use exclusively). I think I've tried all possible menu settings even remotely related to flash function, as well as all the various shooting modes (one-shot, servo, etc.) and have come up empty. My camera firmware version is 1.0.4 if that matters.

I don't know about Sigma but the focus assist beam on the Yongnuo and Canon ETTL flashes work fine on the XSi /450D in both the camera's manual mode and the flash's manual mode.

Well, that was strange. I cleared all camera settings and now it works. Even after I put all the menu and custom functions back to where they were. And what makes this real strange is that I've got 2 cameras and it was the same story for both of them. Oh well, it's working now.

Your autofocus mode has to be One Shot, not AI servo.

Curtis N wrote in post #15656229
Your autofocus mode has to be One Shot, not AI servo.

Actually I tried both ways and it didn't matter. I'm now thinking that the firmware upgrade fixed it, but that I initially overlooked the last step of the upgrade (removing the battery and then replacing it after a few seconds).

Anyway, as always I appreciate the input from everyone.