<P> In 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". Differences in lens aberrations and aperture shape cause some lens designs to blur the image in a way that is pleasing to the eye, while others produce blurring that is unpleasant or distracting--"good" and "bad" bokeh, respectively . Bokeh occurs for parts of the scene that lie outside the depth of field . Photographers sometimes deliberately use a shallow focus technique to create images with prominent out - of - focus regions . </P> <P> Bokeh is often most visible around small background highlights, such as specular reflections and light sources, which is why it is often associated with such areas . However, bokeh is not limited to highlights; blur occurs in all out - of - focus regions of the image . </P>

What is it called when you blur the background in a photo