Nikon D200 + Nikkor 17-55 f/2.8 @ 40mm — 1/250 sec, f/2.8, ISO 100 — full exif & map
Most of this shot is out of focus
(but that's okay)
The Japanese word boke (ぼけ) in Japanese photography refers to the out-of-focusness of some objects in a scene, such as the foreground and background leaves of the image above. Although the word's rominization as “boke” makes it look like a one-syllable word like the English “poke”, it's a two syllable word that sounds similar to “bouquet” (i.e., like “bow-keh”).
When this word is used by English-speaking photographers, it's often written as “bokeh” so as to make its pronunciation more apparent to, well, other English-speaking photographers. When used in English, the meaning changes a bit as well.....
While in Japanese it refers to the fact of something being out of focus, in English it refers to the subtle aesthetic qualities of how that out-of-focusness appears. Two otherwise comparable lenses can produce very different looks for the out-of-focus areas of an image. For example, one lens might produce soft, smooth, buttery transitions among the out-of-focus elements, while another might produce more harsh transitions. Lenses are said to have, or produce, “good bokeh” or “bad bokeh” (although as with anything artistic, many disagree on which is which). A sense of this aesthetic nature can found in the Japanese word that's comparable to how “bokeh” is used in English: ぼけ味 · bokeaji, literally “taste of the out-of-focusness.”
The current Wikipedia page about bokeh has some examples.
When looking at the full-size version of the image above, the bokeh seems pretty harsh, yet it was taken with a very high-quality lens (Nikkor 17-55 f/2.8) whose bokeh is generally considered very nice. One reason for this picture's harsh bokeh could be the lack of quality of the photographer (me), but it's probably because of the subject: direct sun on leaves heavily laden with the morning dew. (I took it at the Konpukuji Temple six weeks ago, on my photographic outing with Nils.)
I found it particularly interesting because the sun and dew drops and angles were all just right such that some funky circular prism effects resulted, as shown at the bottom of the full-resolution crop below:
Funky spectral highlights in my bokeh