So I know in my mind how to ask this but putting it in words is tough.
I have seen professional photographers using a 5DM3 that when they take a photo and then review or look at it in Playback on the LCD screen of the camera that you can see the focus box right where it was on the subjects face on the screen in Playback after the picture was taken. Now I know it obviously will not print out like that but it is there in camera.
I can see the point, it gives good information and feedback to the photographer on where the focus point was during shooting.
Does anyone know how this is achieved? Is it a setting? Is it only specific to the 5D series? I have a brand new 6D and would love to know if I can change a setting to get this feature active on my camera.