Bokeh is the visual quality of blurred areas in a photograph. Learn its Japanese origins, how lens design shapes it, and how AI bokeh rendering is transforming mobile photography in 2026.
The word "bokeh" did not exist in English until 1997. That year, Mike Johnston, then editor of Photo Techniques magazine, published three articles about the aesthetic quality of out-of-focus areas in photographs. He borrowed the Japanese word "boke" (meaning blur, haze, or fuzziness) and added an "h" to guide English pronunciation. The articles argued that not all out-of-focus blur looks the same. Some lenses produce a smooth, creamy blur that photographers find pleasing. Others produce a harsh, nervous blur with hard-edged circles that distract from the subject. Johnston proposed that this quality, which Japanese photographers had been discussing for years, deserved a name in English. Within a decade, "bokeh" had entered the vocabulary of every photography forum, lens review, and camera magazine in the West. Today, it is one of the most discussed aspects of lens design and one of the most studied problems in computational photography.
Bokeh is the aesthetic quality of the out-of-focus areas in a photograph. It is not the amount of blur (that is depth of field) but how the blur looks. Smooth, rounded, gradually fading circles of blur are generally considered good bokeh. Hard-edged, jagged, or doubled circles are considered bad bokeh. The quality is determined by the design of the lens, specifically the shape and number of aperture blades, the correction of spherical aberration, and the optical formula of the lens elements.
This entry covers what bokeh is, how lens design shapes it, its history from Japanese lens culture to global photographic vocabulary, and how AI-driven bokeh rendering is changing mobile photography in 2026.
When a lens renders an out-of-focus point of light, it does not produce a formless blur. It produces a circle, called the circle of confusion or the bokeh circle. The shape of this circle is determined by the aperture opening. A lens with a circular aperture (many aperture blades, well rounded) produces circular bokeh circles. A lens with a hexagonal aperture (six straight blades) produces hexagonal bokeh circles. At wide apertures, where the blades are fully retracted, the opening may be nearly circular regardless of blade count. At intermediate apertures, the blade shape becomes visible in the bokeh.
The quality of the blur within each circle matters as much as the shape. A lens that is well-corrected for spherical aberration produces bokeh circles that are evenly illuminated, with no bright rings or dark centers. This produces a smooth, creamy blur. A lens with undercorrected spherical aberration produces bokeh circles that are brighter at the edges than at the center, creating a ring-like or "onion ring" appearance. This is generally considered unpleasant. A lens with overcorrected spherical aberration produces circles that are brighter at the center, which can look smoother but may produce a different kind of doubling.
Bokeh also changes depending on whether the out-of-focus point is in front of or behind the focus plane. Some lenses produce smooth bokeh behind the subject (background bokeh) but harsh bokeh in front of it (foreground bokeh), or vice versa. This asymmetry is caused by the lens's residual spherical aberration and is a property of the optical design, not a defect.
The Japanese photography community had been discussing bokeh since at least the 1960s. Japanese lens designers at companies like Nikon, Canon, and Pentax were aware that different lens formulas produced different out-of-focus characteristics, and Japanese photography magazines published bokeh comparisons decades before the term reached English. The single lens most associated with the development of bokeh as a concept is the Nikon 105mm f/2.5, introduced in 1971. Its Sonnar-type optical formula produced a particularly smooth, creamy bokeh that Japanese photographers praised. The lens became a reference point for "good bokeh" and is still sought after by photographers today.
Before the term "bokeh" existed in English, photographers described the phenomenon indirectly. Lens reviews in the 1970s and 1980s talked about "out-of-focus rendition" or "background blur quality." The concept was understood but unnamed. Mike Johnston's 1997 articles gave it a name and a framework for discussion. Johnston distinguished between "good bokeh" and "bad bokeh" and argued that the quality of out-of-focus areas was as important as sharpness in evaluating a lens. The articles were controversial at the time. Some photographers argued that bokeh was subjective and unmeasurable. Others embraced the concept immediately.
By the 2000s, bokeh had become a marketing term. Lens manufacturers began advertising the number and shape of aperture blades as bokeh-related features. The Canon EF 85mm f/1.2L II, released in 2006, was marketed partly on its bokeh quality. The Nikon AF-S 85mm f/1.4G, released in 2010, was similarly promoted for its smooth out-of-focus rendering. The trend continued into the mirrorless era. The Sony FE 85mm f/1.4 GM (2016), the Canon RF 85mm f/1.2L (2019), and the Nikon Z 85mm f/1.2 S (2023) all emphasize bokeh in their design and marketing.
Sugimoto's Theaters series, begun in 1976, turns the concept of bokeh inside out. He uses large-format view cameras stopped down to small apertures, producing maximum depth of field. The screen is a blank white rectangle because the movie projected on it averages out over the long exposure. There is no bokeh in these images, and that is the point. By eliminating the out-of-focus blur that photographers usually seek, Sugimoto creates images that are about time, not optics. His work is a useful counterpoint to the bokeh-obsessed mainstream of contemporary photography.
Kawauchi's photographs, collected in books like Utatane (2001) and Illuminance (2011), use shallow depth of field and natural light to create images where the subject is sharp and the world around it dissolves into soft, luminous blur. She typically shoots with a 6x6 medium-format camera, often at wide apertures. The bokeh in her images is not a technical effect. It is part of how she sees. A flower, a bird, a drop of water: each is isolated from its context by focus, and the blurred surroundings give the sharp subject a quality of dreamlike attention.
Leiter's color street photographs of New York in the 1950s and 1960s use shallow depth of field and weather to create images where figures and surfaces blur into each other. He often shot through rain-streaked windows, using the defocused droplets as points of bokeh that sit on the picture plane like abstract marks. Untitled (Snow) (c. 1957) shows a figure walking through a snowstorm, the foreground snow rendered as soft circles of light. Leiter was not thinking about bokeh as a technical term. He was painting with a camera, and the out-of-focus areas were his washes.
Araki's photographs, whether of flowers, Tokyo streets, or his private life, use bokeh as an emotional tool. His close-up flower photographs, in particular, use wide apertures to isolate a single bloom or petal against a background that melts into soft color. The bokeh in Araki's work is not smooth and creamy in the conventional sense. It can be nervous, textured, even aggressive. His images demonstrate that "good" bokeh is not always smooth bokeh. The quality of blur should serve the image, not the other way around.
Smartphone cameras have tiny sensors and short focal lengths, which means they produce deep depth of field naturally. To simulate the shallow depth of field and bokeh that a portrait lens produces on a larger sensor, phones use computational bokeh. The camera estimates a depth map, identifies the subject, and applies a blur to the background. The quality of this simulated bokeh depends on the accuracy of the depth map and the quality of the blur algorithm.
In 2026, the state of the art in computational bokeh has advanced significantly. At CVPR 2026, vivo Camera Research presented MagicBokeh, a diffusion-based framework that produces photorealistic bokeh on mobile devices. The paper, an oral presentation at the conference, describes a unified model that jointly handles bokeh rendering and super-resolution, solving the problem of applying bokeh to low-quality zoomed images. The model uses a focus-aware masked attention mechanism and a degradation-aware depth module to improve depth estimation from poor-quality inputs. Read the paper at CVPR 2026.
At AAAI 2026, researchers introduced BokehFlow, a depth-free framework for controllable bokeh rendering using flow matching. Unlike previous methods that require depth maps, BokehFlow synthesizes bokeh directly from all-in-focus images, with text-prompt control over focus regions and blur intensity. This means a photographer can type "focus on the person on the left, strong bokeh" and the system renders the effect without needing a depth sensor. Read the paper at AAAI 2026.
The NTIRE 2026 workshop hosted the first Controllable Bokeh Rendering Challenge, with 44 registered participants. The challenge evaluated methods on portraits with complex bokeh, using both quantitative metrics and an expert user study for perceptual quality. Most teams refined the Bokehlicious baseline method, and the results showed that diffusion-based approaches are becoming the standard for high-quality computational bokeh. Read the full report at arXiv.
Also in 2026, researchers introduced AnyBokeh, a physics-guided framework for "any-to-any" bokeh editing. Instead of requiring an all-in-focus input, AnyBokeh estimates the source blur state and transfers the optical characteristics of the source lens to a new focus and aperture setting. This means you can take a photo shot at f/8 and edit it to look like it was shot at f/1.4, with the bokeh characteristics of a specific lens. Read the paper at arXiv.
Bokeh is the visual counterpart of depth of field. Depth of field describes how much of the scene is in focus. Bokeh describes what the out-of-focus parts look like. Both are controlled by aperture, but bokeh is also determined by lens design in ways that depth of field is not. Bokeh connects to long exposure photography, where small apertures and long shutter speeds often produce deep depth of field and minimal bokeh. It relates to film photography, where the grain and tonal rendering of film interact with bokeh to produce a particular look. For the broader context, read our post on photography as fine art, or explore our entry on digital photography.
Bokeh is best appreciated in prints, not on screens. A screen displays bokeh as pixels, but a printed photograph renders the gradual tonal transitions of out-of-focus areas in a way that reveals the lens's character. Look at Saul Leiter's chromogenic prints at the Howard Greenberg Gallery in New York, or at the Hamiltons Gallery in London, which holds a significant collection of his work. Rinko Kawauchi's books and prints, exhibited internationally, show how bokeh can function as a structural element in a body of work rather than a single-image effect.
For more on the technical and aesthetic context, read our entries on depth of field and the Zone System, or explore our post on Cartier-Bresson and the decisive moment.
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