Can't work out how to turn on AF assist beam on 1D Mark II

Started Feb 18, 2010 | Discussions thread
Doug J Forum Pro • Posts: 10,235
AF assist is closed loop AF

Cesare Ferrari wrote:

You're a star - this was exactly the problem. I have always used the camera with continuous AF, set to the * button. Turning it back to single shot, and the assist beam works.

I've just had another look in the manual and found no mention of this....

Thanks again,


Patrick J. wrote:


I don't know how it works for your camera, but on my 5D II the AF assist beam does not work if AF is in continuous mode, it has to be in one shot AF.

Hope it helps...

A good point by Patrick.

Something worth noting is that when using AF assist, it's a closed-loop process, unlike other shooting without the AF assist. After the lens elements drive to the position they were commanded to, the camera will take another look at the focus and determine if focus is within acceptable limits. If the focus is not within limits, the process will be repeated.

The focus should be more accurate & predictable in low light, but the AF and shutter release might sometimes be slower.

Scroll down about 2/3rds of the page of this article by Chuck Westfall from Canon.

Best regards,

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