back-button autofocusing

guys here is a very cool tip for DSLR users out there, irregardless of what brand or model, it's called BACK-BUTTON AUTO-FOCUSING, you might have heard of this before but for some who does not have an idea, here it is, it's simple really, all you have to do is;

1.set the autofocus point to the center spot, then point that where you want to focus, and finally press the back button to automatically focus on that point.Its that simple, so from here on,all the shots you take from that position, that focus will be maintained (the camera won’t randomly focus into the background anymore).nice

Back-button focusing is especially helpful for photographing moving subjects, like birds in flight or other wildlife: just switch on the continuous focusing mode, set the autofocus point to the center spot, and hold down that back button. Now you don’t have to worry about accidentally hitting the shutter button while you’re tracking the subject in your viewfinder.