With the right Aperture setting, the bokeh effect can be very powerful in portraiture. Bokeh is the technical term for the skill in portrait photography that is usually used to separate the subject from the background. The bokeh effect is achieved by manually changing the aperture. Aperture is the size of the hole that allows light in. Aperture settings enable you to take little details out of the background, and sometimes even wash the entire background out, depending on all of your settings.
The dramatic impact of this photographic technique draws the eye toward the feature or features the photographer wants the viewer to focus on. The technique is also useful in documentary photography as it gives perspective to situations with many variables. Documentary photography usually specializes in capturing a ray of environments or it focuses on telling a story during an event.