Bokeh - Depth of Field

All about Bokeh 

 n photography, bokeh (originally /ˈboʊkɛ/, /ˈboʊkeɪ/ BOH-kay — also sometimes pronounced as /ˈboʊkə/ BOH-kə, Japanese: [boke]) is the aesthetic quality of the blur produced in the out-of-focus parts of an image produced by a lens. Bokeh has been defined as "the way the lens renders out-of-focus points of light".

In order to create an image that contains what is known as “good” bokeh, the photographer must first find a subject which is easily captured in a close up or short focal distance. For this discussion we’ll select a daffodil blooming in the bright spring sunshine. We will want to be sure that the sun shining down on the bloom is also apparent in the background behind it. This is the way to allow the points of light behind the flower to be forced out of focus and create the round blooms which are so common to images relying on bokeh for their overall effect.