Bokeh comes from the Japanese, noun boke which means "blurred or fuzzy")
Which today is is a term in photography which refers to of light sources appearing in a portion of a photo created by a lens employing a shallow field depth which is out of focus. Different camera lenses produce their own unique aesthetic aspects of backgrounds in images that are out of focus, which are many times used to decrease distractions and put the emphasis on the primary subject.
When Did the Usage of Bokeh Begin?
Former Photo Techniques magazine editor. Mike Johnston, claims that he created the bokeh spelling in an attempt to suggest the proper pronunciation in the English language , replacing the prior bole spelling which came direct from a Japanese word meaning "fuzzy" which had been used since 1996. It is often pronounced as /'bo?ke/ or /'bo?k?/ (boke-uh or boke-aay ).
The bokeh term has appeared in books on photography since at least 2000.
Although difficult to measure, some lenses augment overall image excellence by producing a more subjective although pleasurable out-of-focus regions, simply called bokeh. Bokeh is very important on macro lenses,, large-aperture lenses, and long telephotos since they are typically employed with a shallow field depth. Additionally bokeh is important for "portrait lenses" (medium telephoto lenses, most typically 85mm through 150mm on a 35-mm SLR format
equivalent as the photographer would more often than not choose a shallow field depth (large aperture) to accomplish a background that's out-of-focus to make their subject be more noticeable.
Each detail of light in these out-of-focus regions is converted into a replica of the aperture, typically a rounded disc more or less. Depending upon the way a lens has been corrected for spherical aberrations, these discs may be brighter close to the edge, uniformly illuminated, or more brilliant near the center. Poor correction for spherical aberration of a lens will show one type of disc for those out-of-focus regions in the front of the focus plane, while having a different type for regions in back of this focus plane. This may in reality be more desirable, as dimmer blur circles near the edges create less-defined shapes that blend more smoothly with the encircle image. Lens makers such as Canon, Nikon, and Sony build lenses engineered with specific restraints to alter the rendering of these out-of-focus regions.
The aperture shape is a big factor on the subjective bokeh quality. When stopping down a lens becoming less than the maximum aperture opening (minimum f-number), the out-of-focus tips become blurred and converted into the polygonal image of the aperture and not perfect circles. This is more noticeable when a lens creates undesirable, rigid-edged bokeh,
spurring some lens makers to create curved edge aperture blades to allow the aperture to more closely resemble a circle instead of being a polygon. Lens creators also expand the amount of blades to accomplish the same result. Traditional "Portrait" lenses, like those 85mm fast focal length versions for 35mm SLR cameras often introduce nearly circular aperture diaphragms, which is the situation with the Canon EF 85mm f/1.2L II lens or the Nikon 85mm f/1.4D, which are traditionally thought of as exceptional performing lenses. Catadioptric telephoto lenses feature bokeh resembling doughnuts, as a secondary mirror which blocks the center portion of the aperture gateway.
Leica (which used to be Leitz, (Where Leica only refers to their camera body up until the last few years) lenses, especially vintage lenses, are often argued to stand out in this area, however Leica photographers have been more inclined to use the maximum aperture more often because to the ability of the lens to maintain excellent sharpness at wide aperture openings plus the aptness of the Leica system for reporting and existing-light theatre work. As a consequence, more evidence is required to determine if the lens engineers at Leica's
purposefully set out to create pleasing bokeh.
Bokeh can be emulated by rolling an image with a corresponding kernel of the image with an out-of-focus point supply captured with an actual camera. Although diffraction may modify the effective blur shape. Some graphics editors employ a filter used to do this, most often labeled "Lens Blur". It may also be simulated employing a Quartz Composer Defocus filter within the Mac OS X Leopard plus in Photo Shop Elements using Gaussian blur which is often used for saving time or when genuine bokeh is not needed.
Sep 4, 2011