Some cameras have the ability to back button focus but what's the point in this and should I use it, when people keep saying I should???
This article will take you through " Back Button Focussing " , the WHAT the WHY and the HOW
LINK Why not give it a try? I use this method now and it is a little strange at first but its worth the effort
Hope this answers the question - Back Button Focussing - What is it and should you be using it?