# Speedlight help



## awinphoto (Jan 11, 2015)

Okay guys I have a question for you. I have an assistant who has a 5D Mark II and a 6D. Both cameras when using a speedlight, either the 580 or 430, will not emit the AF focus assist beam. Both flashes work good on my cameras so the flashes are good. And to throw a wrench in everything, when put on the green mode, the AF light comes on, so it must be a setting. I crawled theough his settings and his speedlight custom settings allow for AF assist beam. I don't see anything stopping it. Any suggestions?


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## neuroanatomist (Jan 11, 2015)

The AF assist beam doesn't work in AI Servo mode. Maybe that's it?


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## awinphoto (Jan 11, 2015)

Thanks neuro! That was it! I was going crazy trying to figure it out


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## RLPhoto (Jan 11, 2015)

Off the top of my head, it's a C-fn for a assist beam. It doesn't work in Servo mode and i'm not sure if it works in Back button focus single shot. You can try resetting the camera defaults and the speedlite defaults to get the beam working to start off and reset up the camera.


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## neuroanatomist (Jan 11, 2015)

Glad it's sorted. 

@RLP, the assist beam works in One Shot whether AF is assigned to the shutter release, a back button, or both. 

Edit: I don't recall if the AF assist works in AI Focus mode, and I can't check since the 1-series don't have that option.


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## awinphoto (Jan 11, 2015)

neuroanatomist said:


> Glad it's sorted.
> 
> @RLP, the assist beam works in One Shot whether AF is assigned to the shutter release, a back button, or both.
> 
> Edit: I don't recall if the AF assist works in AI Focus mode, and I can't check since the 1-series don't have that option.



I use AI Focus and the beam works in that mode. So AI Servo is a no-go in that regard. Thanks for your help!


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