I have an XT, and a 550EX flash. The focus assist light, however, will not come on in "P" mode or any other creative zone mode. In Green mode, however, the flash assist light works.

I have checked the custom functions and made sure the "external flash emits" option is selected. Still didn't work. I cleared all the custom functions. Still doesn't work. I reset all camera defaults. Still doesn't work.

Any ideas what may be the issue? If I am trying to take a flash picture in dim light, I obviously want the flash assist beam to activate. Thanks!

Follow up: never mind. I just cleared all the camera settings again and the focus assist light now works in P mode. Any insight on what the issue was? (Now I have the annoying little beep to get rid of. :))

The AF Assist doesn't work in servo focus modes, only in single-shot. Any chance that in the P mode it was switched to servo?

The AF Assist doesn't work in servo focus modes, only in single-shot. Any chance that in the P mode it was switched to servo?

That's the first thing I thought of too, and I could have sworn that it was in one shot mode. I must have been mistaken though, since it now works fine now that I have reset the camera's settings. Oh well, no matter.... I wish all my problems were as easy to solve as this one was. :)