John Suler's Photographic Psychology: Image and Psyche
When we think of a good image, the words clear, crisp, or sharp might immediately come to mind. After considering the issue just a bit more, and surely after viewing truly good photos as determined by people of reputable taste, we’ll conclude that blur plays an important aesthetic role too. In fact, it might be the blurry parts of an image, and how they interact with the crisp parts, that result in an outstanding picture.
We might even realize that blur is one of the things that is intrinsic to photography and therefore makes it unique. When painting or drawing, artists always have the power to render everything in sharp clarity. In photography that might only be possible under certain fortuitous conditions. Blur also distinguishes the camera from human vision. Although we tend to think of the camera as a mechanical version of the eye, they actually record the world quite differently. With its amazing versatility for almost instantaneous focusing as it darts across a scene, the normal eye can make everything in its field of view seem perfectly clear, whether nearby or far away. Not so with the camera.
A beginning lesson for anyone learning photography is “depth of field” – sometimes abbreviated dof. The term refers to the area of a photograph that appears acceptably sharp. Depth of field may be small or large depending on two basic factors. Larger lens apertures (smaller f stops) result in a more shallow depth of field, while smaller apertures (larger f stops) result in a dof that’s wider. Focusing distance also is a factor because the closer you get to the subject you want to focus on, the more shallow the depth of field around it. Some people will also add that focal length is inversely related to depth of field, which means a wide angle lens gives you more while a telephoto lens gives you less. You could consider this just another way of thinking about focusing distance because a telephoto lens seems to bring you up close to the subject while a wide angle lens makes it appear further away.
All of what I just said is a bit of a simplification, because the whole story about depth of field would require a very technical discussion of optics that goes far beyond the intent of this article. If you want to learn more about those technicalities, search online for articles about dof and “the circle of confusion.” But don’t be discouraged if you end up feeling like the term unintentionally suggests – confused. It’s heavy duty stuff.
Instead, here in this article, let’s turn to a more aesthetic topic known as “bokeh.” In the mid 1990s this Japanese term was first proposed to photographers as “boke” by John Kennerdell, who was then commissioned to write an article about it for Photo Techniques magazine. Mike Johnston, at that time editor of magazine, added the “h” to help people pronounce the word, which sounds like “boke-uh” or “bow-keh.” He also wanted to put an end to the jokes that were starting to surface about how it rhymed with bloke, toke, and joke. The original Japanese word can be translated to mean blurry, fuzzy, dizzy, or confused. It’s sometimes used to refer to people who are fuzzy or confused in the head. As we’ll see in a moment, these meanings can be helpful in designing images with compositions that are intended to convey a particular feeling or idea.
Most people who value the concept of bokeh will tell you that the term doesn’t sinply refer to the blurry areas of a photo, but rather specifically to the aesthetic qualities of the blur. What is the “feel” of the out-of-focus areas? Is it pleasing and beautiful, or distracting and ugly? We might compare it to the use of the word “bouquet” in describing wine - which, perhaps not coincidentally, is pronounced somewhat similarly to “bokeh.” What qualities of aroma are appealing and delightful in wine? Bokeh can present very amazing tones, colors, patterns, and layering. These aspects of the image create the feeling, the aroma, of a certain kind of light.
Transition Bokeh: There are at least four types of bokeh. The first is transition bokeh. It’s the blur that results as the dof gradually fades out, when sharp areas transition to being out of focus. But at what point is that out of focus area simply out of focus, and when in the continuous transition does it become bokeh? That’s hard to say. People usually think of bokeh as a blurry area that isn’t easily recognizable as anything in particular, or at least it doesn’t look much like the thing you think it is. So if you examine the above shot of the paint splattered bench, where does the bokeh begin?... You decide.
Background Bokeh: The second type is background bokeh. Think of an outdoor portrait of a person from the waist up, and an attractive blurry background that looks like it might be leaves and flowers. Portrait photographers often use background bokeh. When done well, it greatly enhances the portrait. In fact, many people tend to think of bokeh as being this background type.
Foreground Bokeh: However, foreground bokeh is possible too. Some people think it’s too distracting and don’t like it as much as background bokeh. It seems to block the eye’s path to the subject that is in focus. But that’s not necessarily true in all cases. In fact, an eye-catching foreground bokeh might enhance the composition.
Similar to the above shot of the paint-splattered bench, you’ll often see images involving an in-focus area that gradually transitions away from us into background bokeh, or one that gradually changes to foreground bokeh as it moves towards us, or one that does both. It’s an interesting effect. The in-focus area seems to resolve from or dissolve into the background or foreground blur, or it emerges from a sandwiched position between the background and foreground bokeh.
Glint Bokeh: The fourth type is glint bokeh. It’s the blurry circles or patches of light from lamps, light bulbs, or small shiny surfaces in the background (and maybe sometimes in the foreground). Distant points of light, especially in a dark scene, light shining though leaves, and specular reflections in daylight often create pleasing bokeh. In fact, when many people talk about bokeh, it’s often this backgrond glint type that they’re referring to.
Some people say it’s a subjective preference as to when glint bokeh is good or bad. Others have distinct opinions about the issue. They’ll probably say that bad glint bokeh are patches or circles that appear too harsh and bright, have sharp edges, or look like over-exposed blobs. If the bokeh circles have bright edges and a dim center, look like rolled up condoms or donuts, appear swimmy or like flat and perfectly circular disks, that’s not good, because they tend to distract the eye away from the subject. If they are regularly shaped polygons - like a hexagon, which actually reflects the shape of the lens diaphragm - that’s not too great either. The ideal circular bokeh, they’ll probably say, are spheres of light with the brightest part near the center. The glow from the center point of light smoothly expands outward, gradually becomes more dim and blurry, and ends in a soft outer edge – similar to what you would get if you created a white circle in Photoshop and then applied some Gaussian blur, as in the illustration above (although even "good" lens blur rarely occurs in such a smooth Gaussian fashion). That softening towards the perimeter allows the circular blurs of light to blend nicely into each other and the surrounding areas of the image, resulting in soothing bokeh. The same principle would apply to background bokeh that isn’t produced by glint: points and lines should gradually fade towards their perimeters in a silky smooth transition, rather than having sharp outer edges that interact with each other, creating wiry, harsh, or otherwise distracting patterns and textures. Chromatic shifts might also occur near the edges of the blur, resulting in the color of the blur patterns being different near the inside and outside areas.
So how do you get that “good” bokeh? If you do an online search of the topic, you’ll find lots of advice. Unfortunately, similar to information about the circle of confusion, the issue gets complex. Other than what I already mentioned about aperture size and focusing distance, it boils down to lens design, including such factors as the shape of the aperture and how a lens corrects for spherical aberration. However, cheap lens sometimes give you good bokeh while expensive ones sometimes don’t (they usually give you a soft evenly bright disk). When comparing lens it’s also possible that one will produce good bokeh in some situations, while another may perform better under different conditions.
For those photographers who work a lot with bokeh, some manufacturers sell lens with special controls for changing how out of focus areas are rendered. For the rest of us, we might simply experiment with the lenses we have to see what kind of bokeh they produce. We also might not concern ourselves too much with the distinction between “good” and “bad” bokeh, according to the criteria mentioned above, but instead think about how the bokeh serves the composition by producing the desired perceptual and psychological effects. We might consider the following issues:
Sensation and Feeling: What sensation or feeling does the bokeh tend to create? Does it feel like sunlight, being outdoors, fire, or lamps? Is it sparkly, dreamy, dizzy, confusing, exploding, gentle, scary, soothing, joyful, sticky, creamy, flowing? Does that feeling complement the intended emotional tone of the subject, or perhaps contradict it in an interesting way? Jagged, sharp, harsh, edgy, or blobby bokeh might be the right effect in some images. Consider the situations in which our human vision might produce bokeh - as when we squint our eyes while looking at light sources, or when our vision goes blurry as our state of mind changes. Are we staring into the sun, drunk, slipping off into reverie or unconsciousness? How might those sensations serve the composition?
Subtlety and Distractiveness: How subtle or distracting is the bokeh? If you want to keep the viewer’s eye on the subject that’s in focus, you might prefer the blur to be gentle and unobtrusive, as do many portrait photographers. If you want the eye to move around the image, or the blur to compete with and even overwhelm the subject, go for bokeh that’s loud. Keep in mind that the human mind usually tries to avoid the uncertainty and ambiguity of blur. Bold bokeh will pull at the eye, but the eye won’t want to stay there long. It will probably shift back and forth between the blur and the subject that’s in focus. Think about whether and how that movement works for the image. On the other hand, gentle bokeh might feel soothing and pleasing, even though the viewer may barely notice it. By creating contrast, soft bokeh allows the subject in focus to really pop in vividness and clarity.
Movement: In addition to the movement I mentioned above, how might bokeh generate a sense of motion? Does the changing dof create the feeling of something coming towards us, receding from us, or maybe both? Think about how dof and bokeh sensations address the concept of the image: does it feel like something is progressing, fading, approaching, emerging, sinking, surfacing, dissipating, compressing, escaping, releasing, or marching? If the image also contains motion or camera shake blur, how does that interact with the bokeh?
Shapes and Patterns: Bokeh containing lines and different tones or colors will create various shapes and textures. How do those tones, colors, shapes, and textures interact with the subject in focus? Do they echo, compliment, contradict, or compete with the tones, colors, shapes, and textures of the subject?
Layering and depth: Background and foreground bokeh can create a feeling of depth and layering. Bokeh can be layered or overlapped onto itself or other areas of bokeh. That also creates the sensation of depth.
Ambiguity: Some blurry elements challenge the viewer to figure out what the blur might be. How might that temptation affect the viewer’s attitude about the subject in focus? Does it create curiosity, mystery, confusion, frustration, humor?
It’s interesting how, when given a choice, people often prefer photos, especially portraits, that contain bokeh over those that do not. As I mentioned earlier in this article, that's not how our eyes see the world. Our eyes focus so quickly as they dart around a scene that everything seems to be in focus – unless you stare at something without letting your eyes move, as if you're slipping into a trance or dream-state. Then the background fades and smoothes out, as in bokeh, leaving only the subject emerging in sharp clarity. Perhaps that’s what people enjoy, almost on an unconscious level: the trance-like focus on the subject, as the rest of reality dissipates into a dreamy blur.
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