Story
Selective focus is simply using Shallow Depth of Field/Low Aperture to isolate a subject. Two aspects of the story are being shown at the same time.  
  • It allows you to focus on one part/subject of the story 
  • While blurring out another part of the story/subject  
Below:  We see that the Step Mother is smiling but there seems to be something out of focus in the background that is part of the story.  We don’t know why until we also see
examine Snow White on the ground out of focus.  The Selective focus gives the photo context/story.  
The shot below is from Defiance and is an example of selective focus. While there are subjects walking behind and in front of Daniel Craig’s character, our focus is on him.  
 
You can direct the focus of the viewer toward whatever you desire to showcase. You are telling the viewer “this is important.”

Using Selective Focus you can create a very intimate scene. By putting other people and elements out of focus you can really focus and connect with what is happening in the story.
        
Baby Announcement
  • The football with shoes tell us that a baby is coming.  This is where the “selective” focus of the story is.  The blurred parents in the background are apart of the story but are not the focus.  The two parts together create the story.
Engagement
  • Focus is on the ring and wedding date
Family
  • The “selective” focus is on the couple.  We can tell that they are in love.  The blurred children in the back of the photo tells the viewer that not only is this couple in love but they have children. The in focus and out of focus parts come together to tell the whole story.
Wedding
  • The “selective” focus  on a pile of dress shoes.  The background out of focus area of the girls getting ready gives the story context.
My Boys
  • The “selective” focus  is on the little Jedi.  The background out of focus area shows another little Jedi.  We now know that he is not alone but we are not sure if he is a friend or foe.