I would like to say first off I love the 5D3 AF and think it is very good. It is very accurate and has allowed me do do things I couldn't have dreamed about with my 5D2. However, there is one tiny issue that kind of bugs me and I was curious if anyone else has experienced this. I have two 5D3s and they both do this. With one shot AF in dim-dark situations it seems like it will focus quickly at first and then hunt a little before it finally gives me the red light to shoot. During a reception last night I finally just switched over to AI servo and it was fast as lightning in pretty dim light. Accuracy was really good as well. I went into the menu and adjusted the setting that allows the camera to take the picture before "focus" is achieved in one shot mode and I liked it better. It is like the camera achieves focus almost instantly but the red light has a small delay. In a brief test I took several shots after focus but before the red light and found that almost all of the time the camera focuses just fine initially and doesn't benefit from the additional hunting before it shows red. I hope that makes since. Anyone else have a similar experience.