What is Bokeh?

Bokeh is the term that refers to out-of-focus areas behind, or in front of, the plane of focus. This term is a simplification of the Japanese term “boke aji”, which originally translated as “confused light” but is more recently interpreted as “lens blur”. There seems to be some variation in the pronunciation of bokeh, but I prefer to pronounce it “BOH-kay”, which seems to be a common pronunciation. (For some reason, my wife thought I was writing about flowers). The term appears to have caught on in the U.S. around 1997 when a photo magazine began using the term to describe out-of-focus areas in photos. Since then, there has been a growing interest in bokeh as an aesthetic element in photographs and lens manufacturers have responded by including design features that will help produce pleasing bokeh in addition to other lens attributes.

While bokeh is easy to see when it is present in an image, it is more complex than it appears. What do the blurry areas look like? Is it good or bad? Most agree that bokeh which provides a soft, smooth, dreamy looking blur with no distracting highlights is “good” bokeh, while “bad” bokeh may have odd looking circles, hard edges, and other distractions in the out-of-focus areas. Two different lenses that provide equal sharpness may produce different looking bokeh in the out-of-focus areas. This difference is related to the design and quality of the glass, the shape and size of the aperture, and the number of blades in the iris diaphragm. Specular highlights in the out-of-focus areas may produce odd ovals from the aperture which can be distracting. Slight differences in aperture settings, focus distance, or distance from the focus plane to the background or foreground can have a dramatic effect on bokeh. In some cases, the background bokeh may look different than the foreground bokeh.

When evaluating your photos, in addition to checking for sharpness, it is useful to study the bokeh and look for subtle differences that might help or hurt the overall appeal of an image. What could you have done differently to produce a more pleasing bokeh? Ultimately, whether bokeh is good or bad in your photos is largely a matter of your judgment and photographic intent.

Using an appropriate combination of the following techniques will help maximize the quantity and quality of bokeh:  

·         Use the largest format camera you have. (Cell phones just won’t do!)

·         Use a long lens, the longer the better. (Prime lenses generally produce better bokeh than typical zoom lenses.)

·         Use a wide aperture, usually the wider the better.

·         Keep camera-to-subject distance small.

·         Keep the subject distance to background and foreground as large as possible. (Keeping the camera position as close to the ground as possible will often achieve this nicely, especially when photographing on a beach or other flat open areas. Accompanying photo of the Semipalmated Plover illustrates this.)

·         Avoid backgrounds and foregrounds with specular highlights, high contrast, irregular patterns, and distracting colors. (See accompanying photo of the flower.)

·         Use a quality lens, well corrected for spherical aberration.