7D 19 point autofocus - what's the point?

[pmack]

I typically always use the single center point for autofocus, however there are times when multi point is usefull.

Yet from what i've experienced, the default Auto select 19 point AF is dreadfull.

It seems to always front focus.


An example:

Photo 1 - Auto select 19 point AF


50% crop




Photo 2 - Single Point


50% crop



Shots were taken on a tripod with cable release, 1/800s, shot wide open (f/4) to help show focus issues.


My only explanation is that because there are so many active focus points searching for a lock, if one point is only going to be correct only 90% of the time (for arguements sake), then you only have a 13.5% chance of all of the 19 points being correct with each shot.

But yeah i dunno.

Is this just how it is supposed to be? useless?

thanks