Bokeh

This is a Japanese word to describe the particular visual quality of out of focus areas in a picture. You might think it hardly matters what things look like when they’re out of focus, but there’s a bit more to it than that. ‘Bad’ bokeh produces unnatural-looking outlines and highlights, while ‘good’ bokeh looks ‘creamy’, smooth and natural. Good bokeh is associated with the shape of the diaphragm in the lens – more aperture blades and rounded aperture blades produce a more circular shape and better bokeh. Some photographers confuse bokeh with how out of focus a subject is, but that’s not the same thing. A lens with a wide maximum aperture can make background objects extremely defocused, but that doesn’t mean they have good ‘bokeh’.