What Is Bokeh?
Understanding Background Blur in Fotography
Bokeh is the term used to describe the appearance of the out-of-focus areas in a foto, particularly the background.
You've probably seen portraits where the subject is beautifully sharp, but the background is soft and blurry. That's often the result of using a wide aperture, such as f/1.8 or f/2.8.
Bokeh isn't simply about how blurry the background is. It's also about the quality and appearance of that blur, which can vary depending on the lens you're using.