t3i won't AF in low light NIGHTCLUBS anymore (using 550 ex)

[vicdamonne]

I do nightclub photography and I've had my t3i for about 2 years now and I use the 550 ex.  Recently the red light doesn't blink when I try to get a focus in low light using the kit lens.

I know the red light does work because I used it with a trigger and I've put the flash on a 7D and it works fine.  In order to get a focus now in low light, I have to use a secondary video light for the camera to focus.  The camera's AF works fine in regular light and in dim light- just not in a dark nightclub (but it used to).

[hsbn]

Check to see if Focus Assist with External Flash has been turned off or not.

[MikeSowsun · Accepted solution]

Make sure your camera is set to "One Shot" AF as the assist light on the flash does not work if the camera is in "AI Servo" AF. 

[vicdamonne]

WOW.. Thanx Mike.  I don't know HOW the camera got switch to AI SERVO (I don't even know what that means...lol)

Camera is working PERFECTLY now- no more blinding people in the club with my extra bright video light to get a focus.

Thanx