Bokeh – meaning & use in photography

Sometimes in our lives, especially when we had to deal with photography, we have encountered the following term : “Bokeh”. You may have heard it spoken by someone, or just read it, heard it on TV or a video online, “Bokeh” is becoming more and more used, as photography started to be more and more accessible to so many. Well, it has this strange Asian sound and flavor, so what could it mean?

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Fujinon XF 16-55mm F2.8 @ F2.8

The word “Bokeh” actually comes from the Japanese word “boke” ボケ, which means “blur”. The “h” at the end was added to emphasize on the correct pronunciation by the English speakers. “Bokeh” refers to the quality and aesthetics of the blurry parts (out of focus areas) in an image, taken by a photographic lens. It is not something you could really mathematically measure, or quantify, but more of an aspect which relates to photographic artistic principles.

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Fujifilm X100S with Fujinon 23mm F2 @ F2

Bokeh can be assessed by the people who have a certain level of photography knowledge, people with a strong sense of art and creativity, although a photograph with great bokeh can please the eyes of neophytes, more than other photographs, even if they don’t totally understand where that “inner beauty” comes from and what techniques were used in capturing that attractive image.

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Fujinon XF 16-55mm F2.8 @ F2.8

So, if “bokeh” refers to the blurry parts of the image, it means that the image has a main subject that is in focus (most of the times, unless for artistic reasons) and this subject is isolated from a distracting background. Here, people can easily mistake “bokeh” with the amount of blur in a photograph. Well, bokeh it’s not really the amount of blur, or the blur itself. The blur, or the background blur is the result of a shallow depth of field which creates a separation to emphasize on the main subject.

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Fujinon XF 55-200mm F3.5-4.8 @F4.5

Ideal for portrait photography, when the artist needs to create a strong focus on the main subject (a face, a person, the eyes, etc.) which magnetizes the public attention and creates a strong emotional message. The background would be distracting, with a much less artistic value, if everything in the frame would be in focus (like in most landscape, macro, product or travel photography).

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Pentacon Auto 135mm f2.8 @ F4

But it is all relative, because the are no rules that say a portrait should definitely have an amazing bokeh and if everything is in focus and your photograph lacks a shallow depth of field, then its artistic value would be compromised. No way! This is the beauty of photographic art : the artist is free to create, according to the original inspiration and only sky is the limit here (if you know how to overcome the technical limitations of your gear, too).

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Canon EF 50mm F1.8 II @F2.2

Coming back to the “Bokeh” concept; what does influence the Bokeh in a photograph? How can we create images with a pleasant bokeh, images that really pull the main subject away from the distracting background? Well, I could say that bokeh depends on 6 factors and I will just enounce them in quite a random order, because for others, my order of importance could not be the same.

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Helios 58mm F2 @F2

A. Sensor size in your camera.

It is a technical fact and I will not bother your with some weird scientific details, that are not so relevant in this article. But the larger the sensor in a digital camera, the shallower the depth of field it creates. A Micro 4/3 sensor, found in Olympus and Panasonic mirrorless cameras will render a more pleasant bokeh and shallower depth of filed, than a compact camera, or smartphone can do. An APS-C sensor is even better (found in most of enthusiast and sometimes professional cameras), like the one that I have on my Fujifilm cameras. A full-frame sensor is even larger and this can be found in professional cameras. Beyond that, we go to the Medium Format area, which is a really different universe.

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Helios 58mm F2 @F2.8

B. Lens aperture.

This is more captivating, because it is one of the essential factors that most of the people would think about, when dealing with bokeh and subject isolation in photography. It is also a technical fact which relates to the way the rays of light travel through the lenses and reach the digital sensor that captures the light information and transforms it into digital information. Each lens is equipped with an iris, an aperture, which changes the amount of light that reaches the sensor. There are different types of lenses and this aperture can be controlled manually, via an aperture ring on the lens, like on the old lenses from the Film Era (and some modern lenses, like Fujinon lenses from Fujifilm, equipped with an aperture ring, even though the changes are made by-wire), or electronically, via a dial, or buttons on the digital camera.

 

The most common “F stops” (values of a lens aperture) that comes since the beginning of photography are : F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, F22 and sometimes F32. Each stop of light doubles the amount of light if we go backwards (from a bigger F value to a smaller F value) and the reciprocal, each stop of light diminishes by half if we go forward (from a smaller F value to a bigger F value). At F2, the sensor will receive half of the amount of light available at F1.4.

 

This variable aperture in a photographic lens, aside from managing the amount of light that enters to the sensor, has also a “side effect” (and it is such a beautiful effect) : it modifies the depth of field. The more we open the aperture, the shallower the depth of field can be achieved . This is why, “fast lenses” like F2.8, F2, F1.4, F1.2 and even F1.0 (there are some lenses that go to F0.85, for example) are so loved by artists, while being the most expensive, due to the technical challenges of manufacture. The faster the lens, the better for bokeh and subject isolation.

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Fujinon XF 35mm F1.4 @F1.4

C. Aperture blades.

I am talking about the shape and number of the aperture blades. For example Leica and Carl Zeiss, when manufacturing those lovely film lenses, they used to reach amazing levels of beautiful bokeh with their apertures made of 11 or 15 iris blades. And the rounder, the better, even if this means a very complex design and a real challenge to put it into production, hence the big prices. The more aperture blades (and rounder), the more creamy and sweet and artistic the bokeh.

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Pentacon Auto 135mm f2.8 @ F4

D. Distance between the camera and the subject.

The closer you get to your subject, the shallower the depth of field and a more efficient subject isolation from the background.

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Helios 58mm F2 @F2

E. Distance between the subject and the background.

For a better subject separation from the distracting background, you need to place your main subject as far as possible from the background plane. If you do portraits and you subject stands only 1 meter from a wall, you will not get a real subject isolation from that wall, because the subject is placed almost on the same spatial plane with its background. Try again, moving your subject away from the wall several meters and you will get a better subject separation.

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Canon EF 50mm F1.8 II @F2.8

F. Focal length.

Also a major player in this Bokeh game. Portrait lenses have some particularities that are not found in an ultra-wide lens, designed mostly for landscape and architecture. Let’s not forget, in landscape and architecture photography, almost all the times, you need your entire frame to be in focus, sharp and nice. This is why a very wide lens may not require so many aperture blades. But for portraits, you need a strong and efficient background separation from a very wide aperture, a very shallow depth of field and great bokeh for captivating artistic outcomes. And the longer the lens, the stronger the compression onto the subject, related to the background. You get superior result using a lens between 50mm and 200mm for portraits and bokeh and subject isolation, than using a wide lens.

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Fujinon XF 16-55mm F2.8 @ F2.8

 

In the quest for the perfect bokeh, all those factors must be merged in a harmonious synergy. Of course, we are all restricted by our financial and technical limitations, but we should not be narrowed by the lack of knowledge and the freedom of creativity. So, have a great light and happy shooting!

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Helios 58mm F2 @F2

All photos and text – © Sebastian Boatca 2015 / www.sebastianboatca.com

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