Tutorial: Bokeh (Background Blur) 101

Editor’s note: We published this tutorial last month but I believe many of you may have missed it, so here it is again.

Many beginner photographers consider their cameras to be good if the latter can produce very sharp pictures. But professional photographers appreciate a camera (or more precisely, a camera’s lens) that can take a sharp main subject and an out-of-focus background. By throwing the background out of focus (i.e. blurred), the main subject is isolated and seems to “pop out” of the picture for maximum impact.

How do we add background blur to our pictures? By using a large aperture on a standard or telephoto lens. On a 35mm camera lens, an aperture of f/4 is considered large enough to throw the background nicely out of focus. Unfortunately, on most compact digicams, the focal length of the lens is too small to be able to throw the background out of focus even when you use a relatively large aperture.

Bokeh is the out-of-focus areas -- I like this picture even though the background is distracting

Professional photographers love a good background blur. In fact, there is a term that is used to denote especially good “background blur quality”: bokeh. But what is bokeh and how do you include it in your pictures for the most impact? Learn how to add background blur to your pictures and lift them to a whole new level.

Bokeh (or, bo-ke) is the out-of-focus areas of an image that surround your main subject. It is a Japanese word that means “fuzzy,” “haze,” “blur,” or “blur quality.” Depending on how the “blur quality” is rendered by your camera’s lens, bokeh can be distracting or exquisitely beautiful. Bokeh is a function of the lens and a lens that renders a beautiful bokeh is highly prized by photographers.

Bokeh Rosa
Creative Commons License photo credit: Amy Dianna

Good bokeh

Bokeh is most visible around, but not limited to, points of light. A beautiful bokeh results when the lens renders the out of focus areas more or less as circular shades of light that blend smoothly with the surrounding area. Bad bokeh is jagged and discordant.

so young...
Creative Commons License photo credit: nosha

Good bokeh -- background isolates bird

a Thanksgiving treat
Creative Commons License photo credit: nosha

Bad bokeh -- distracting background

Since bokeh is a function of the lens, you just have to buy the right lens, correct? Yes, except that lenses that produce beautiful bokeh tend to also be quite expensive. If you can afford them, go for it. If not, don’t despair because there are other (software based) techniques that you can use to produce pleasing enough bokeh in your pictures.

C-dub Light
Creative Commons License photo credit: Voxphoto

Good bokeh

Try this. Set your lens to its widest aperture and zoom in (step back if you need to) and take a picture of a main subject close to the lens and a busy background a few metres away from the main subject. Focus on your main subject and let the background go out of focus. Now you can examine the out of focus areas to see if your lens gives good or bad bokeh.

What if you find that your lens does not create good bokeh — or, as is most common on compact digicams, no bokeh at all? You can then create bokeh in software. Image editing software use filters to artificially create blur.

Remember that even if your lens produces bad bokeh, your image may still be overall a keeper. As a photographer learning about bokeh, do not get upset if others point out the bad bokeh in your pictures. As I said, the picture itself may be beautiful overall (whether the bokeh is good or bad). But as you learn to spot the difference, you come to appreciate good bokeh for what it is.

Here are some examples where people confuse good and bad bokeh, and even what bokeh really means — it is the overall effect that wows them:

It seems that “circles of light” have become a cool thing to have in your pictures these days. It’s all thrown in pêle-mêle under the attribution of “Bokeh”:

Graphic designers have latched on to bokeh and have used it ad nauseum in their Web designs. They have zeroed in on the bokeh effects around points of light that produce circles. Here are examples of so-called “bokeh effects” used as backgrounds on Web sites. In these cases, good or bad bokeh loses its meaning and, again, it’s just the overall graphic effect that the designer is after. The pictures are pretty but not examples of good ‘Bokeh’:

Here are a number of related links that explain the subject of background blur, especially relating to bokeh, in more detail, including a software to produce bokeh and even a Background Blur Calculator for those who love these things. You’ll find examples of good and bad bokeh as well as some lenses that produce especially good bokeh.

Related Links:

To recap, you can capture images with out-of-focus backgrounds with all fast lenses [‘fast’ here means ‘that have a large aperture’], but the quality of the background blur is what determines whether the bokeh is good or bad. If you want good bokeh, save, save, save for those lenses that give good bokeh.

Which lenses should you be concerned with bokeh? Portrait lenses (medium telephoto lenses) need to isolate the main subject from the background, so a good bokeh is important. With macro lenses and long telephoto lenses, we also get short depth of field, so a good bokeh is important. Most wide-angle lenses are used for landscape work where the whole scene, from near to far, need to be in sharp focus, so bokeh is not as important here.

Check this article for a list of lenses that give good bokeh.