Bokeh is a term that photographers throw around a lot. It refers to the shape and quality of the blurred area in a photo. Most noticeable is how specular highlights and point lights are rendered, but it̵
How to pronounce “Bokeh”
Pronounced “boh-keh”, this term comes from the Japanese word “boke,” which means something that is close to the blur or the haze, although much more nuanced. In 1997 the “h” of was added Photo techniques Editor Mike Johnston, so the written form was more like the pronunciation.
Both syllables are stressed equally – it is not “boke” (rhyme with poke) or “boh-kee”. “Boh-kay” is pretty close because Japanese, like any language, has regional differences. You can check out this video to hear the right (and almost every wrong) way of saying bokeh.
Depth of Field and Bokeh
Bokeh is really a subjective assessment of the quality of the objectively blurred areas of an image. An image in which the blurred areas look good and contribute to the aesthetics should have “good bokeh”.
An image where the blurry area distracts or affects aesthetics can be referred to as “bad bokeh”. However, since this is subjective, people may not agree on whether a photo has good bokeh or bad.
Since bokeh is only relevant when large parts of an image are out of focus, it is usually associated with photography where a shallow depth of field is desired, such as in a picture. B. portrait or animal photography. It’s also associated with macro and sports photography as it can be a side effect of equipment or circumstances.
Of course, an image captured for any style of photography can have bokeh. We’ll talk more about the bokeh quality later, but let’s talk about the depth of field first.
The depth of field is the amount of the focal plane that is acceptably sharp for the viewer. It is what determines what is in focus or out of focus in an image. In an image with a shallow depth of field, such as the portrait above left, only a small part (in this case only a few millimeters) of the focal plane is in focus. You will find that even the model’s ears are slightly blurry.
In an image with a great depth of field, like the one in the photo above, everything is in focus. The depth of field is influenced by the focal length of the lens, the aperture to which the lens is set, the distance of the subject from the camera and the size of the camera sensor.
What is important for bokeh is not so much that images have blurry areas, but rather how they are rendered. If something is outside the depth of field, it will not be reproduced exactly on the camera sensor, but will be reproduced as a blurred circle.
This phenomenon is known as the “circle of confusion”. This is most evident with point light sources, which is why lights and other highlights are so visible when they are out of focus.
However, like anything to do with optics, there are a little more nuances. Point light sources are theoretically only rendered as circles. What they actually look like depends on the design and construction of the lens. That also determines the bokeh quality.
Factors Affecting Bokeh
Various lens design elements affect the appearance of bokeh. The first is the number of aperture blades in the lens. Those with fewer aperture blades create more polygonal circles of confusion. For example, a lens with seven aperture leaves creates heptagons, while a lens with nine (or more) more rounded bokeh creates.
The aperture of the lens also affects the bokeh. A larger opening creates a larger, more rounded bokeh. With narrower openings, the shape of the iris is more precisely defined, be it a circle or a polygon, and the circles of confusion are smaller.
All photographic lenses have spherical aberration. The steps you take to correct this will also affect the bokeh of an image. A lens that corrects the spherical aberration strongly has confusion circles that are brighter on the outside than in the center, which is known as the “bubble” effect. A lens that does less correct the spherical aberration has the opposite effect: circles of confusion with bright centers and faded edges.
The angle at which light enters the lens also affects the bokeh. At the edge of an image, circles of confusion are often represented as ellipses rather than circles, in what is known as the “cat’s eye” effect. With some lenses, the cat’s eye effect is so strong that the bokeh looks like it is swirling in a circle.
Good bokeh, bad bokeh, ugly bokeh
It’s probably pretty clear by now, but photographers have gone mad deep into bokeh. There’s a lot of discussion about what makes bokeh good or bad, but there are a few points that are worth highlighting.
Bokeh is a subjective assessment of the quality of the objectively blurred areas of an image. Good bokeh doesn’t necessarily make a good photo. A boring subject with appealing bokeh still makes a boring photo, the blurry areas just look decent.
Avoid always using the largest aperture to chase bokeh, and think that this will improve your images – there’s a lot more to it than that.
The photographer makes bokeh good or bad. Some people hate the bubble effect, while others buy lenses specifically to create it. However, in general, smooth, circular bokeh is considered better looking because it is the least distracting from the subject.
In our opinion, the image above has what we think is good bokeh, while the image below is bad. The fuzzy areas are just too textured and noticeable, and the soap bubble effect is very noticeable.
Capture bokeh in your images
We generally don’t recommend taking photos only of blurry backgrounds (that’s a cliché at this point). There are a few things you can do if you want to improve the quality of the bokeh in your images, or at least have more creative control over it.
Using a top quality lens with a large maximum aperture will give you more comfortable bokeh than consumer zoom lenses, especially if they are designed for portrait or macro photography.
Shoot with the largest aperture possible so your subject is still in focus. Sometimes that means wide open, but others require you to use a slightly narrower aperture to get anything you want in focus.
Think about your background too. Point lights and bright highlights (like raindrops reflecting off leaves) provide the best-defined bokeh, while dark shadows tend to render indistinctly.
If you keep the distance between the subject and the background as large as possible, you will get the blurrest background, and therefore smoother bokeh. Longer telephoto lenses also increase this effect, as long as you can keep a good distance between the subject and the background.
Learning how to precisely focus your camera is also important. Some situations that result in good bokeh can be difficult for your camera’s autofocus system.
Experiment and play around. Capturing good bokeh is one of those things that you can really only learn if you do, because it’s subjective.
Why your smartphone has to fake Bokeh
Most modern smartphones have a portrait mode that, among other things, blurs backgrounds to emulate the bokeh of a lens with a large aperture. Whether the effect looks good or not is up to you, but why it needs to be faked is interesting.
To achieve good bokeh, an image needs parts of the foreground or background to be out of focus. As described above, the aperture, focal length and sensor size affect the depth of field.
While smartphone cameras have large fixed apertures (often 1: 1.8 or 1: 2.0), the focal length of the lenses is very short (generally between 2 and 6 mm). Since they also have very small sensors, the crop factor means they have the same angle of view as wide-angle or regular lenses on a full-screen DSLR.
Here’s the catch, however: the crop factor only affects the apparent field of view, not the depth of field. The decisive factor is the actual focal length of the lens. The lenses of smartphones have very short focal lengths. This in turn means that there is a very large depth of field and therefore no bokeh.