5D III and EX 580 II flash problems

[Barrfly]

I purchased a 5D mkIII back in April as an upgrade to my 7D, I've been very happy with the new camera until the other evening when I was shooting in some low light situations with the flash.
For reasons that seem to be eluding me I can't find the setting in camera to activate the focus assist beam from the flash. It fires with the proper exposures though I have to switch to live view for my auto focus to lock on.
When the same flash is on the 7D this is not an issue, the auto focus assist beam kicks in as needed .

Has anyone else had this problem with a 5Dmk III ?

 

[Old Shooter]

Try this...

Menu, Camera Settings, External Speedlite control, Flash C.Fn settings, AF-assist beam firing = Enabled...

Note - Your Speedlite has to be mounted and switched on to access that part of the menu...

Hope this helps!

 

[Mathias]

Make sure that you are in "One Shot" mode and not in "AI Servo". That is the most common reason while AF assist lights do not work.

 

[Barrfly]

Thank you both for the advice.
It was the servo mode that did me in . One little flick of the select dial to one shot and all is good with the world again !

 

[kaihp]

I just tried to do the same with my 5D3 and 580EX (Mk I). The 5D3 keeps saying that the flash is either not turned on or not compatible, when I try to enter the Custom Functions menu on the camera (yes, I did set One Shot AF). My old 50D does the same, but at least it has a direct menu point where I can direct it to use the flash for AF assist light.

Bad flash?

 

[robertbanksoz]

hopefully you dont have a bad flash, as the 580's aren't cheap
good lucky with it