12.20.2013

Micro Rant. Bokeh is not = to shallow depth of field. Really. It's not.


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 photographybokeh (Originally /ˈbkɛ/,[1] /ˈbk/ boh-kay — also sometimes heard as /ˈbkə/ boh-kə,[2] Japanese: [boke]) is the blur,[3][4] or the aesthetic quality of the blur,[5][6][7] in out-of-focus areas of an image. Bokeh has been defined as "the way the lens renders out-of-focus points of light".[8]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.[3] 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 four 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.





21 comments:

Matthew Hunt said...

While we're (justly!) quibbling about words, the website you cited is Wikipedia, not "the Wiki." Wiki is a generic term for a technology, the technology that Wikipedia is built on. There are lots of wikis that aren't Wikipedia.

Kirk Tuck said...

Schooled again....

Anonymous said...

Your rant is my rant, your rant is my rant. From the Bokeh nonsense to the redwood forests. This rant was made for you and me!

We need to track these people down and force them back to school.

The only bokeh most people know is a bunch of flowers.

Dave Lemieux said...

Kirk, Thank you for addressing this as it is a pet peeve of mine. I've actually read comments on other boards where readers claim sensor size effects bokeh. I think "the quality of" should precede the word bokeh every time it's used to lessen any confusion. BTW- great blog! I love reading from actual professionals.

atmtx said...

Kirk,

Nice writeup. I find it quite amazing how often this term is misused and mispronounced too.

I did a writeup about it a year ago. And also explain how the word is supposed to be pronounced.

http://blog.atmtxphoto.com/2012/12/24/happy-holidays-see-you-next-year/

Claire said...

Yup, this is why I often use "defocus" instead, it's shorter than "out of focus areas" or "background blur", but more gramatically correct than bokeh. I use bokeh as meaning... well, bokeh !

Michael Matthews said...

Well, the sad fact is language is dynamic. What many of us see as a slide into ignorance and chaos, many happily adopt as acceptable use.

If I were acting in my usual capacity as curmudgeon in high dudgeon I would point out that the use of "fun" as an adjective is grating (adjective) on the brain. Each and every time it's encountered. On the other hand, it is also perfectly acceptable use going back to the 1950s or '60s.

I guess it's a matter of where you draw the line and who's drawing it.

Jim said...

I've had the same complaint for years over other terms. People morph language according to fad. Someone bends a term in some way and others think it sounds cool so they slavishly copy so they can be cool too. Unfortunately it usually ends up with one group not understanding what another is saying because they don't realize they are talking about two different things while using the same words. Effective communication is hard enough. We shouldn't be complicate it by using words to mean something other than what they were designed to mean.

John said...

Nice to see someone take the time to lay this out. It seems that young digital photographers have dropped DOF from their vocabulary - everything is 'bokeh' now - wonder what's next in the lexicon.

Mike M. said...

Kirk, our pal Mike Johnson was an early popularizer and user of the term.

Here's some 2009 comments of his on the topic:

http://theonlinephotographer.typepad.com/the_online_photographer/2009/01/what-is-bokeh.html

Mike M. said...

Kirk, our pal Mike Johnson was an early popularizer and user of the term.

Here's some 2009 comments of his on the topic:

http://theonlinephotographer.typepad.com/the_online_photographer/2009/01/what-is-bokeh.html

rlh1138 said...

As usual, enjoy reading what you're thinking about. In this case I must say however, in your quest for 'more accurate exchanges' could talk a bit about 'nervous blur' - I always get that one mixed up with 'excited blur'. And also, a bit more about 'smoother transitions'. Smoother? Gradations of color closer in hue? My heavy handed point being, I think the subject matter ( subtle characteristics of a lens's ability to render images) is subjective and does not have widely accepted definitions. But.. could be it does and just me and my friends don't know them. Apparently bokeh does tho... hmm.

Happy Holidays down there

Anonymous said...

Ouch.

But "Bokeh" already IS a shorthand for describing the subjective effects of certain optical aberrations, and it has a number of increasingly silly (and equally unquantifiable) sub-categories such as "hairy bokeh" and "cross-eyed bokeh".

Let's not see photography devolve into the new high-end audio, shall we? If you insist on precision in your terminology, far better to use terms like "spherical aberration", which actually have meaning. Likewise in audio, "Vacuum tube smoothness and warmth" has no real meaning, but "Even-ordered harmonic distortion" and "Damping factor" do.

Jeff S

thequietphotographer said...

Bokeh, out of focus, blur or...I don't discuss this but of one thing I'm sure: your model is beautiful :-)
robert

Scott said...

How about the confusion of "equivalent" focal lengths and apertures? I actually wrote a long post on another forum suggesting we start talking about the actual angle of view (10 degrees, etc) rather than a "24mm equivalent" in some not full-frame format. The conflation of f-stop with depth of field is even sillier, as DoF is obviously dependent on so many other things as well.

Scott said...

How about the confusion of "equivalent" focal lengths and apertures? I actually wrote a long post on another forum suggesting we start talking about the actual angle of view (10 degrees, etc) rather than a "24mm equivalent" in some not full-frame format. The conflation of f-stop with depth of field is even sillier, as DoF is obviously dependent on so many other things as well.

Unknown said...

Hi Kirk,

I love that picture. What did you take it with?

Craig Yuill said...

I wonder if the misuse of the term bokeh could be mitigated by phrases that consistently include both the word and references to out of focus areas. Example: "The out-of-focus areas have smooth bokeh.". Maybe people will eventually get it.

tesilab said...

I believe you overgeneralized the meaning of "nervous" bokeh. I believe more specifically, nervous bokeh refers to the phenomenon of doubling of the blurred image. Other artifacts, such as hard edged rings, color fringes, swirliness, unround highlights, etc. would not in themselves qualify as "nervous".

Stan Yoshinobu said...

I have also noticed the misconception that mingles amount of blur and the quality of the blur. Some of it just slang, like when people say this is my "DOF lens."

For M43 the bokeh of the Panny 25mm f1.4 is wonderful. I also like the bokeh of the 35-100, and I have seen good examples of smooth bokeh from the Oly 75/1.8.

More important than all this is bokehliciousness. I can't believe people are stuck on bokeh, when they should be thinking about bokehliciousness

Paul Crouse said...

Hi Kirk,

Why don't we think about the bokeh of the lens in the same way that we think about the bouquet of a wine?

It is something that is not easy to describe but we know it when we see it.

Living here in Japan for nearly 2 decades, when I first heard the word "bokeh" that is what I thought it meant. The pronunciation in Japanese is the same, by the way.

Personally, I prefer the phrase "special sparkle."

Paul Crouse
Kyoto, Japan