Sorry to all if this has been posted earlier, but how do I set my camera up for this? I know about the option within the camera's menus where it allows you to say you want "51-pt 3D", but I have never seen this phenomena where the viewfinder lights up with all the relevant focusing areas. Am I on the right track, but need to set the camera to AF-A? I'm confused. Sorry again for sounding like an idiot.