Today’s Question: Much has been written since the term “bokeh” was first introduced 20 years ago. As I understand it, it is based on the design of modern lenses to create a certain effect of the background or shadow. Photography has been around far longer that 20 years. What is your take of the artistic element of bokeh? Is it a real compositional element or just another device by the techies in our art.
Tim’s Quick Answer: I think of the bokeh quality of a lens as an additional creative decision the photographer is able to make. Sometimes you might choose a specific lens because of the bokeh quality (or other behavior based on specific lens attributes). In other cases, that bokeh may simply be a “side effect” of other intentions you had as a photographer.
More Detail: In many respects “bokeh” is just a fancy way of describing the visual appearance of out-of-focus areas of a photo. In particular, when photographers refer to bokeh they are often referring to how relatively bright highlights in out-of-focus areas are rendered, which in turn is impacted by the shape of the lens aperture.
There are many reasons you might choose a particular lens for a given photographic situation. For example, you might choose a lens with a short focal length because it has a wide field of view. Coincidentally, that same lens might have a lens aperture with nine blades, but that might not have any effect on the photograph you are currently capturing.
In other cases, the fact that there are nine blades on the lens aperture for a given lens might be the specific reason you choose to use that lens for a given photo. For example, when including the sun in the frame I typically opt for a lens with an odd number of aperture blades so I get a sunburst effect with more rays than I would using a lens with an even number of aperture blades.
To me the bokeh quality of a lens is similar. Some lenses have very pleasing bokeh quality, and others render out-of-focus areas in a way you might be indifferent about. In other words, sometimes you might not be all that concerned about how blurred areas of the scene will look. In other cases you might want to choose a specific lens based on how the background will appear.
I think a good example here would be a mirror lens. Many photographers find they do not like the way out-of-focus areas are rendered with a mirror lens, so they might avoid such a lens altogether, or at least for certain situations. This is the type of creative decision you might make about which lenses to buy and which lens to use in a specific scenario, based on the bokeh quality of that lens.
So, while the term “bokeh” may get a little over-used, and might seem a bit cliché, I do think it is worth being familiar with how a lens will render out-of-focus areas. In other words, as always it is important to understand your equipment, so you can anticipate the results you’ll get, and so you can choose the best gear for achieving your photographic vision.