Bokeh: Adding Blur Quality to Backgrounds

In my last post, I defined bokeh as a “nice blur effect.” That’s true in a general sense, but bokeh is so much more. In common usage, bokeh refers to patterns of blurred lights or shapes within an image. Another way to look at it (no pun intended) is how out-of-focus points of light are rendered – not in a technical sense, but in an artistic one. According to Ken Rockwell (see below), “Bokeh is not how far something is out-of-focus, bokeh is the character of whatever blur is there.” In other words, it is the aesthetic quality of the out of focus (outside the depth of field) areas of the image.

The term “bokeh” in digital photography has been in use since the mid to late 1990s. It derives from the Japanese words “boke”, which means blur or haze, or “boke-aji”, the blur quality. For more about how “boke” became the Anglicized “bokeh”, see Mike Johnston’s on-line column Bokeh in Pictures.

Bokeh results from a wide-open aperture (f/1.4 up to f/5.6) and a shallow depth of field. The subject is close to the lens and the background and light source are farther away. As you might expect, this will yield a background that is very softly focused or blurred. Recall photos where Christmas tree lights or city street lamps appear as soft circles of brilliant light against a softly focused or blurred background. This is a classic example of bokeh.

Amy Renfry clarifies the difference between soft focus and bokeh in her article, What is Bokeh Effect in Photography: “In soft focus photography there is an intentional blurriness added to the subject while the actual edges are retained in sharp focus, but in bokeh it is only an element of the image that is intentionally blurred. Additionally, bokeh tends to emphasize certain points of light in the image as well.”

Consider the three images below. The first is a puppy against a soft focus background. One could argue that the background is a bit monochromatic. Yet, the image still works. The second image shows a helper (Frans Slaman) against a background of trees and the third a dog running the blinds. Notice how the light filtering through the trees and at the base of the blind appear as soft circles that blend into the background. That’s bokeh! It softens the brighter points of light and adds interesting highlights to the background.

Ken Rockwell offers an excellent discussion of the technical aspects of how bokeh is created. If you are interested in a more in-depth discussion than is offered here, check out his article, simply titled Bokeh. If you really want to get into the technical weeds, see H. H. Nasse’s article, Depth of Field and Bokeh, published by Carl Zeiss Camera Lens Division.

The following summarizes Ken’s definitions of poor, neutral and good bokeh:

• Poor Bokeh. Occurs when the blur circle (out-of-focus point of light) has a sharply defined edge, bright edges and a dim center.
• Neutral Bokeh is a technically perfect and evenly illuminated blur circle, but the edges are still too well defined. As a result, out-of-focus objects, either points of light or lines, appear as reasonably sharp lines in the image due to the sharper edges of the blur circle. Many quality lenses today create neutral bokeh.
• Good Bokeh is characterized as a blur circle with an edge that is completely undefined. That is, it blends softly into the background.

The aesthetic appeal of bokeh within an image is subjective. One could argue endlessly about whether an image has poor, neutral or good bokeh, and if your having an image judged, this could be very important. Most often, it is an artistic judgment. For example, the images below show neutral bokeh. If you are after a more textured effect in the background, this isn’t so bad.

To me, this next image of a puppy standing on his hind legs combines neutral and good bokeh very well. The tree trunks are softly focused and exhibit a neutral bokeh, yet the blooms on the crape myrtles are an example of good bokeh and really pop out of the background. It’s a nice counter point to the dark puppy fur.

In Schutzhund (IPO) photography, it can be tricky to work bokeh into fast action images, as photographers like to fill the frame with the dog – an excellent composition technique. Also, aperture and shutter speeds settings are often set to achieve sharp focus, which is not favorable to creating bokeh. But creating bokeh is possible under the right conditions and offers an appealing feature to perk up backgrounds. Give it a try, and let me know how it goes. Until next time, Happy Shooting!

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Going Artsy With Depth of Field

This past week I had an opportunity to photograph dogs, cats and other critters at a friend’s farm. She also owns the kennel where our dogs stay when we’re traveling to places dogs cannot go. The purpose of the photo shoot was to grab some great shots for my BJ Spanos Ink Photography portfolio. The added benefit, though, is I was reminded of how paying attention to depth of field can add an artsy look to photos as well as remove distractions.

How many times have you taken a photo of a Schutzhund (IPO) dog at work and realized that not only is the dog in focus, but so is everything else in the field of view (see image below). I’ve taken plenty – more than I care to remember! Tends to be rather distracting, doesn’t it? The viewer’s focus is diffused over the entire image rather than drawn into the focal point, which in this case is the dog going over the one-meter hurdle.

There’s a reason I used the word “diffused” to describe the viewer’s experience, as it directly relates to depth of field. Consider the image below.

The background is diffused, and the dog and helper are in focus as is a bit of the foreground. The viewer’s eye is drawn right to the action, even though there’s a bit of interest in the upper right with the horses grazing. It adds a bit of symmetry to the image.

As a review, depth of field is the area of acceptable focus or sharpness. It extends from the nearest to the farthest part of the subject area in focus. Depth of field is controlled via the aperture and focal length of the lens. As you know, changing the aperture size directly affects the overall sharpness of the image. A small aperture, say f/11 or f/16, results in a deeper depth of field than a large aperture, say f/2.8 or f/5. The wider open the aperture, the shallower the depth of field; that is, the less area is within the zone of focus. What this means is at wider apertures, the subject will be in focus, but the area in front and behind the subject may be softly focused and/or even have a nice blur effect, called bokeh.

For a detailed explanation of depth of field and lens focal length, I refer you to Robert Hirsch’s book Light and Lens: Photography for a Digital Age. An earlier post from December 2010, entitled Using Aperture and Shutter Speed Creatively, also offers a good review and discusses how to balance ISO, aperture and shutter speed to get creative images. This post relies heavily on Bryan Peterson’s expertise. Worth re-reading in conjunction with this post.

Back to this week’s photo shoot. Much of the photo shoot took place in a hay field with very tall grass and just letting our two dogs, Kira and Brio, be dogs. They did not disappoint.

This image of Brio showed me how cool “hay on the hoof” looks with a soft focus. It has a neat texture. Yet, Brio is kind of lost in the brush. So, with a bit of cropping, he becomes much more the focal point.

The next image is Kira in the hay and shows the textured look of the blurred out background even better. Also, notice the foreground is blurred too, so that only the area around Kira is totally in focus, especially her face and the ball.

To close out this post are a few additional examples from the photo shoot of how using depth of field can add drama to images, while minimizing distracting backgrounds. They feature two of our friend’s five dogs, one of her 11 cats and one of her three horses, plus a neighbor’s horse. I particularly like the image of the pit bull mix coming into the field of focus, like he’s jumping right out of the picture. So, the next time  you’re out shooting, remember depth of field is more than just getting the subject into focus. It can add interest and drama to your images and help focus the viewer (yea – I know – a pun!). Until next time, Happy Shooting!

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