Out of focus on my shots

[Canonboi]

My sister in law just got married last week and I took a few shots of the event. I was taking a picture of the entourage and I employed the focus and recompose (technique). Then after I took them I checked my shots and a lot of them are out of focus. Then I realized I'm on One Shot AF Mode which made me conclude that when I focused on their eyes while they are walking, and then recompose, my focus is left behind from where I half-pressed (focus) the shutter, so that when I pressed the shutter completely and took the photo, it will be out of focus indeed?

Is my assessment of my fault correct? Do you think I should have used AI Servo instead? Please confirm this.

[Mike]

That sounds about right. If they are moving towards you or away from you then the focus & recompose method won't work. You need to change the af point to the nearest one to their eyes and use ai servo to track them as they walk.

[Canonboi]

Thanks Mike. Very helpful.