Following comments on the thread
Military wedding with the K5 -- the good and the bad post#10 linked image.
I never change from the single point as I assume what is important is in the middle of my frame so why would I want the camera to look and try to get every thing right via 5 or 11 points?
If I am concerned about the camera making a mistake I will often focus on something larger say a persons chest and lock that then recompose rather than try to focus on their face especially if I am far enough away to suspect the single spot might get confused with a the face and say a tree behind as in the example image from FrancisK7.
But what I am now wondering is in that circumstance where there is an other object behind the subject that the single point can also recognise would using the 5 point help to stop the tree rather than the face being the focus point?
Now of course we don't know how far away the camera was from the bride, how far the tree is behind her and what aperture /dof is being used but lets assume for arguments sake that it was f2.8 to deliberately give a shallow dof.
in that case do you think that using the 5 point have stopped the camera focusing on the tree rather than the couple? no probably not but;
Since I would guesstimate that in the viewfinder the 5 points would have covered the couple and the three large trees at least the red indicator might have warned the photographer that he would have a problem.
I have been trying in my garden to replicate the problem with that image but of course I don't have a couple to hand so I used a garbage bin with a large plate standing in the top as a face
but no matter what I do every time it is the centre single point that lights up. I put some dark cloth over the plate to cut the contrast and only once did one of the other indicators light up, which at f2.8, would have definitely make the "face" out of focus and the tree behind in focus.
so back to my original question before I rambled on,
What I don't understand is why the auto with a multi point system is even there ?
under what circumstances would it give you a better, or if you like more correct , focus point than the centre focus only option?
Has anyone had spent the time and effort try to work out a plan/ program [call it what you will] as to when to use the 5 point versus the single point focus system ?