I am still trying to understand why it is not guaranteed to get a sharp picture with AI server for stationary objects with shallow dof as long as light is enough. But there won't be any focus confirmation beep. Considering there is no AF lock with AI Servo, it is not possible to do focus and recompose with it right?. Do I need to always switch to one shot AF with focus and recompose.
If you want to focus and recompose using ai servo then you need to use back button focus. In order for it to work you need to go to the customize settings for the shutter button and deselect the "half press initiates autofocus" option.. That way you use your center point to focus using the back button then let go, recompose and push the shutter button.
I always set one of the custom modes this way along with the fast tracking AF settings you see posted here and on other websites. That way you don't have to fiddle around and make a lot of setting changes to switch back and forth.