SLR Photography

In SLR photography one of the biggest quality issues photographers find is poor focusing. Many assume an SLR will automatically focus exactly on what you want. This is not necessarily true. Automatic Mode (often called "idiot mode" by experienced photographers) can't read your mind. You need to make the camera do what you want.

Credits to : http://www.wikihow.com/Use-the-Manual-Focus-on-an-SLR-Camera