Imagine you have the most amazing subject, a face, an animal, a plant. You want sharp focus on that subject while reducing the background to a pleasant fuzzy blur. That’s bokeh blur, baby, and here’s how to achieve it in lay terms.
Terms to Know
Bokeh – pronounced BO-kay like bow-and-arrow and the name Kay. This refers to that desirable out-of-focus area around your subject.
Depth of Field – the distance between the nearest and furthest objects in your image that are in sharp focus. Anything outside of this, in front of it or behind, is considered out-of-focus.
Aperture – the hole through which light travels in your lens. It is really a fraction, 1 divided by the aperture value, and the smaller the f/# or F#, the wider the tube of light and therefore more light reaching the camera sensor.
What You Need for Bokeh
The term bokeh was adopted in the late 1990’s from a Japanese word that means blur or hazy. That’s what we want, the ‘good’ bokeh (pleasing to the image result) versus the ‘bad’ kind (focusing is generally off throughout the image). But how do we achieve it?
Bokeh is a function of depth of field, and the sharp area for depth of field is determined by the lens. We want a ‘shallow’ depth of field. In other words, we want to make a lens selection that that brings us up close to the subject but not any further. Lenses that do this are generally wide angles and telephotos because they naturally create shallow depth of field.
The lens is also built to a specific aperture fixed or variable value. The wider the aperture (lower f/stop number), the shallower the depth of field. Therefore, it pays to get a lens with the widest aperture value you can afford if you want to shoot for bokeh effects on a regular basis (like portrait work).
How You Make Bokeh
Different lenses may achieve a decent bokeh with varying combinations of focal length and aperture. It depends on the manufacturer and how they constructed the optics. You’ll have to experiment with your lenses to see how best they work for this style of shooting.
(All images copyright © Yvonne Kochanowski 2019. None were retouched or post-processed for this article.)
I grabbed my zoom tele, which happens to be a 55-250mm f/4-5.6. I set the aperture value on my camera to f/4, then focus to the 55mm end of my range. I moved my tripod until this brings my subject into focus, and if I’m lucky, it sets the background to a pleasant blur. Here’s a result:
If you look closely, you’ll see that the raindrops hanging on the leaves and a few of the flowers are in that shallow depth of field to produce a sharp resolution. The flowers closer and further, not in the least.
But what do you do if your background includes lots of busy-ness, like other features that stand out in color contrast to your desired subject? You see what I mean with this shot:
In this case, I look for a different set of ‘stuff’ in the background. I had to change my position relative to my subject, and in this case, it meant also changing the composition a bit. The end results are a wonderful series riffing on this:
Since I was using a fully variable lens, the adjustments to get this in the right focus changed the settings. I couldn’t get any closer, and on a variable aperture zoom lens, changing the focal distance of the lens changes the aperture. That’s the way the shutter clicks sometimes.
If You Don’t Have a Wide Aperture Lens
I don’t. The lowest my lenses go is f/3.5-5.6 on my standard zoom, and I’ll be experimenting with it next. The point is, use the widest aperture you own and play around with it. You’ll be amazed at the results you can achieve if you frame your shots with flexibility in mind and focus on the end result, in this case, a rain-kissed rose.