I don't speak Japanese and I'm not an etymologist but I'm getting really annoyed at the legion of people who've decided (through lack of reading, research, etc. whatever) that the word "Bokeh" is exactly synonymous with the the phrase "out of focus background"; a condition caused by using a lens at an very large f-stop and from a relatively close point of view. It is not. The word Bokeh describes the character of an out of focus area in a photograph.
This is not my opinion. I have a photographer friend who is a native Japanese speaker and an accomplished photographer and he's taken pains to explain the meaning to me several times. In detail.
Here is what the Wiki says: In photography, bokeh (Originally //, // boh-kay — also sometimes heard as // boh-kə, Japanese: [boke]) is the blur, or the aesthetic quality of the blur, in out-of-focus areas of an image. Bokeh has been defined as "the way the lens renders out-of-focus points of light".However, differences in lens aberrations and aperture shape cause some lens designs to blur the image in a way that is pleasing to the eye, while others produce blurring that is unpleasant or distracting—"good" and "bad" bokeh, respectively. Bokeh occurs for parts of the scene that lie outside the depth of field. Photographers sometimes deliberately use a shallow focus technique to create images with prominent out-of-focus regions.
Here is the link to the entire article: http://en.wikipedia.org/wiki/Bokeh
If we are to have rational discussions about aspects of photography I think it is vital that we use the same terms, respect the definitions of existing terms, and understand the words and concepts that we share and discuss. Otherwise we erode our ability to have meaningful discussions and we end up with the blogging equivalent of the Tower of Babel (For Tower of Babel please see the Wiki link here: http://en.wikipedia.org/wiki/Tower_of_bable ). (yes, I see that Babel is misspelled in the link but that's the link.)
Just to be clear, Bokeh, is not a shorthand way of saying, "I put the background out of focus with my long fast lens." It actually means "When I use two different lenses of the same focal lengths but of different construction, and I shoot them both wide open, I find that one has a different quality or set of characteristics in the out of focus areas than the other. They have different Bokeh." The two lenses can be equally out of out of focus due to a small area of sharp focus (depth of field) but the way the backgrounds look can be quite different and that is due to the way each lens is made. Some highlights in the backgrounds might look much harsher on the images made by one lens compared to a lens of the same basic specifications but with different designs.
People who are invested in studying the arcane science of Bokeh will point to lens formulations and even the number of diaphragm blades in the aperture control of a lens as design decisions that influence the quality of the blur.
If one misuses the word bokeh as a substitute for "out of focus" we lose our collective ability to have a meaningful dialogue about more subtle characteristics of a lens's ability to render images. I have four different 85mm lenses and all four, when shot at f2.8 have identical depth of field but all four provide different styles of blur or bokeh. The concept of bokeh can be a powerful descriptor, especially for portrait artists who want images that are easy on the eye. Better bokeh is generally associated with softer and less detailed blurs in the out of focus areas, with smoother transitions. A lens which has distracting Bokeh is often described as having "nervous" blur in the out of focus areas.
Let's please respect the definition of our craft's words. It makes for more accurate exchanges.