Digital Media

Bokeh comes from the Japanese word boke (ボケ), which means "blur" or "haze", or boke-aji, the "blur quality." Bokeh is pronounced BOH-Kə or BOH-kay.

Bokeh is defined as “the effect of a soft out-of-focus background that you get when shooting a subject, using a fast lens, at the widest aperture, such as f/2.8 or wider.”

Simply put, bokeh is the pleasing or aesthetic quality of out-of-focus blur in a photograph.
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Although bokeh is actually a characteristic of a photograph, the lens used determines the shape and size of the visible bokeh. Usually seen more in highlights, bokeh is affected by the shape of the diaphragm blades (the aperture) of the lens. A lens with more circular shaped blades will have rounder, softer orbs of out-of-focus highlights, whereas a lens with an aperture that is more hexagonal in shape will reflect that shape in the highlights. = Nikon USA