Talk:Bokeh

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[edit] Memories

Some may also use this term, loosely, to describe what happens to acutely painful or obtusely humiliating memories that are difficult to live with. The images, or memories (i.e. peoples, places) of these events can be pathologically "blurred" or put "out of focus", to allow them to cope or carry on with their life.

As with Bokeh, the characteristics of these memories may be quantified by the circle of confusion. In out-of-focus areas, each point of light becomes a disc. When referenced in a poetic or a metaphoric sense, the disc could be uniformly illuminated, for others it is brighter near the edge, and for others it is brighter near the center. —The preceding unsigned comment was added by 66.48.17.253 (talk • contribs) 21 May 2004.

Two questions:

1) When you say "Some may also use this term", are you speaking generally? It's a brilliant metaphor to use in discussion, but it's such an obscure reference I wonder how many times you could say it without the other person asking: "Like a -what-?".

2) How does one pronounce 'bokeh'? My estimation: bo(long 'o')-keh (emphasis on first syllable)? —The preceding unsigned comment was added by Apostata (talk • contribs) 26 June 2005.

[edit] Need Title Change to "Boke"

It should be "Boke", which is the proper Japanese transliteration, since there should not be a trailing "h" without a following vowel sound. Pronunciation of the last vowel should be "eh" similar to the vowel sound in "air". Monito 7 July 2005 12:04 (UTC)

No it doesn't need a title change. Although the transliteration is incorrect (I know some Japanese), the accepted term in English for this style of photography now is bokeh. If you're unconvinced, ask google to define "bokeh" and "boke" for you... completely different results. Enochlau 02:04, 11 July 2005 (UTC)
I added a reference to the Mike Johnston column in which he claims that, as then editor of Photo Techniques magazine, he coined the 'bokeh' spelling in an attempt to suggest the correct pronunciation to english speakers, who were inclined to pronounce 'boke' similarly to 'broke', 'spoke', or 'toke'. Matthew Brown 14:03, 19 November 2005 (UTC)
It should be boké or have some other accent on the 'e' to show that the 'e' is pronounced.Cameron Nedland 14:39, 28 November 2006 (UTC)
I agree that bokeh is most common spelling, and the best title for the article. — brighterorange (talk) 18:51, 28 November 2006 (UTC)

[edit] Quality not Quantity

The pictures at the side of the article incorrectly use the term "bokeh" to denote the QUANTITY of blur rather than the QUALITY of the blur that's present. Quantity of blur may be more correctly denoted by the quantity of "depth of field", ie. shallow or deep DOF(as illustrated by the photos). It might be useful to emphasize in this article that bokeh isn't a quantity at all; it's "good", "mediocre" or "bad", but never "lots of bokeh" or "no bokeh". Thedeepabyss 12:57, 27 October 2005 (UTC)

[edit] Mirror Lenses

Is the bokeh of a mirror lens really called doughnut bokeh? I've always heard it referred to as two-line bokeh, because it has the effect of doubling out-of-focus edges. Tom Duff 00:33, 16 November 2005 (UTC)

I've heard the "doughnut" term as well. Matthew Brown 14:05, 19 November 2005 (UTC)

[edit] Images

Morven/Matthew Brown's edit comment suggests a new set of images to illustrate bokeh. I propose three types: An example of a wide-open lens bokeh, circular blobs. Ericd's image that was in the article previously would be a decent but not perfect example. An example of polygonal blobs caused by non-circular aperture blades. And finally an example of a mirror lens bokeh. This could be the above mentioned donut type, and probably the double-edged line preferably in the same example image. I'd like to contribute but I only have a film camera loaded with slide film at the moment (and for some time), with no slide scanner. I also don't have a mirror lens. Ziggur 22:10, 29 November 2005 (UTC)

I'll have a look and see what kind of bokeh I can get from the cheap 50mm lenses on my two SLRs. Only five blades on a Canon FD 50mm f/1.8, so I might be able to show some effects. —Matthew Brown (T:C) 01:07, 30 November 2005 (UTC)
I know that they're my images, but I though that the two jonquil flowers made a nice comaprison. --Fir0002 21:20, 8 December 2005 (UTC)

[edit] Japanese term

Andy Jones left this comment in the article. I'm moving it here and have left a message on his talk page. Imroy 11:55, 25 February 2006 (UTC)

I think the actual term used in Japan is boke aji (ぼけ味）in which boke means blur and aji means taste or flavor,
hence the compound meaning used in the word bokeh in English - the flavor, or quality, of the blurry parts of an
image Andy Jones 03:56, 25 February 2006 (UTC)

[edit] "boke" doesn't mean blur

The actual meaning of "boke" in Japanese is closer to "senile fool". The correct photographic term is "pinboke" ピンぼけ[1]. I confirmed this with a professional translator. —Preceding unsigned comment added by 12.47.58.161 (talk • contribs)

"pinboke" is one relevant term that's used in photography, according to a professional translator I talked to. However, it looks like the previous comment about "bokeaji" ぼけ味 is also correct, and more common[2][3] —Preceding unsigned comment added by 64.170.4.146 (talk • contribs)

Boke ぼけ is the noun form　of the verb bokeru ぼける meaning to blur. Pinboke ピンぼけ means out of focus which is similar but different to blur. Brettr 07:07, 27 November 2006 (UTC)

[edit] commonly repeated misconceptions

This page (as of 15jun2006) contains several common misconceptions and factual errors.

The "hard" or "soft" quality of bokeh is primarily affected by spherical aberration. It has absolutely nothing to do with chromatic aberration, and very little to do with the number of aperture blades (except when hard-edged bokeh makes the shape of the aperture apparent.)

This is pretty much correct. In particular, a mathematically perfect lens would have a OOF blur kernel which is a fairly hard edged image of the aperture. Spherical aberration causes the focus positions of the rays to have an angular dependence. In a lens with spherical aberration light from one side of the focal plane with spread outward from the image of the aperture while on the other side the light will spread inward. The outward spreading is generally considered attractive while the inwards spreading is generally considered ugly. The 'good blur' being in front or behind the focus location depends on on the sign of the spherical aberration. The best way to illustrate this would be to obtain bellows or a tilt lens which is not perfectly corrected for spherical aberration and take a picture which is extremely tilted, thus one side of the frame will show focal positive blurring and the other side will show focal negative blurring. --Gmaxwell 18:26, 25 June 2006 (UTC)

[edit] Disagree

I take issue with this sentence:

Although difficult to quantify, and hence open to debate, some lenses are believed to enhance overall image quality by producing more subjectively pleasing out-of-focus areas (bokeh).

Can't the "look" of the out-of-focusness be characterized by the image of a point source? (Or to be very exact, a point source at each point in space.) That is, at a given distance, can't this effect be considered convolution, and so if you know the kernel, you've quantified the effect? —Ben FrantzDale 20:11, 19 June 2006 (UTC)

  • Yes, the lens can be quantified—but I think the sentence is saying that it is the subjective quality of the bokeh that is hard to quantify. — brighterorange (talk) 18:44, 20 June 2006 (UTC)

[edit] Stefanie with Bokeh.jpg

It's a damned shame they deleted that picture.

That is all I have to say.

– ∅ (∅), 15:35, 26 June 2006 (UTC)

It's easy to replace. Get someone on it. :) --Gmaxwell 16:07, 26 June 2006 (UTC)

[edit] HDR

This article should mention high dynamic range imaging as what would be oversaturated pixels wind up blooming into the visible circles (or whatever other shape) in the final image. The GIMP plugin to do bokeh compensates for lack of HDR by selecting how close to 100%-saturated a pixel has to be to create a circle. —Ben FrantzDale 17:04, 26 June 2006 (UTC)

[edit] Exposure

We should consider how exposre is involved in this. In as much as exposure is exponential and in as much as bokeh is a linear convolution in real-world brightness, it must be a nonlinear convolution of recorded image intensity. This might explain why I needed to mess with gamma before and after convolution while making Image:Faux-bokeh-final.png. —Ben FrantzDale 17:04, 26 June 2006 (UTC)

Only if you're talking about working with images in non-linear space. Normally images are just 2.2 gamma or the SRGB non-linear space (which is mostly 2.2 gamma). The nonlinearity is mostly invertable, so you can still achieve the same effect by normal convolution. --Gmaxwell 17:24, 26 June 2006 (UTC)

[edit] Bokeh or not...keh?

Are the star-shaped artifacts around the streetlams in this picture bokeh, or a different type of artifact? Digital camera, long-exposure shot. Rawling4851 22:26, 17 January 2007 (UTC)

Those are some sort of lens flare. (It can't be bokeh because the lights themselves are in focus.) —Ben FrantzDale 00:08, 18 January 2007 (UTC)
Right, I see the distinction. But the shape of the flasre is still determined bythe shape of the aperture, like the shape of a bokeh? Rawling4851 00:12, 18 January 2007 (UTC)
Diffraction around the aperture? (Diffraction spike)155.212.242.34 (talk) 19:49, 20 November 2007 (UTC)
Yes, it's caused by diffraction - IIRC - and as far as I remember from my photography classes, it depends on the aperture size but not on the shape (i.e. number of blades). Blue.death (talk) 14:55, 8 January 2008 (UTC)
Bokeh consists of a complicated combination of geometric and diffraction effects. Extreme diffraction effects can be considered an extreme case of bokeh if you like. Dicklyon (talk) 16:14, 8 January 2008 (UTC)
And the shape of the aperture does affect the resulting bokeh; a star-shaped aperture would produce a star-shaped bokeh effect. - ∅ (∅), 20:47, 8 January 2008 (UTC)
These artifacts are easily accomplished with a star filter. The effect varies depending on how many sets of parallel lines are scored into the filter, and how deep the scores are. Then again, in this particular picture, the exposure is very long, perhaps allowing normally imperceptible streaks to gather in a detectable manner. —Nahum Reduta (talk) 02:29, 9 January 2008 (UTC)
I don't think such a filter has been used in Rawling's photo, IMHO. It's diffraction caused by the selected aperture and long exposure. I have shot plenty of night shots obtaining the same effect. Aperture shape does affect bokeh, but does it also affect this 'star effect'? - Blue.death (talk) 09:18, 9 March 2008 (UTC)

[edit] Rewrite

There seems to be an undergoing rewrite by Redikufuk (talk • contribs • count). I've posted a friendly notice on their talk page encouraging them to discuss it here. - ∅ (∅), 20:32, 24 January 2007 (UTC)

This article made more sense before Redikufuk replaced it with a lot of ten-dollar words. I'm reverting it wholesale. - ∅ (∅), 20:14, 20 March 2007 (UTC)

[edit] Deviation from disk

It appears that there are several causes for bokeh to not be disk shaped. First, there is the aperture shape. A mirror lens causes donut bokeh; a fuzzy-edged aperture would make a soft-edged blur spot. Second is aberration such as spherical aberration causing bright edges, and coma. Finally, I see diffraction around the aperture as a source of ring-shaped bokeh or of just bright edges. Can anyone comment on the magnitude of these effects? 155.212.242.34 (talk) 19:52, 20 November 2007 (UTC)

I'm curious as to how various animals 'perceive' bokeh. For instance, cats and snakes have vertical irises, whereas toads and goats have horizontal ones. Cats in particular would seem to benefit from being able to detect unfocused lateral movement (such as a mouse sprinting along the ground). —Nahum Reduta (talk) 02:51, 9 January 2008 (UTC)

[edit] Consensus on italicization

Can we get some agreement across the article on whether it needs to be in italics? --Dante Alighieri | Talk 19:37, 14 December 2007 (UTC)

Use usual English typography rules. When you're talking about bokeh, no italics; when referring to the word bokeh, you do. Dicklyon (talk) 16:13, 8 January 2008 (UTC)
See Use-mention distinction —Nahum Reduta (talk) 02:32, 9 January 2008 (UTC)

[edit] Circle size

I know I've seen somewhere a discussion of the size of the bokeh disk (the circle of confusion) as a function of camera parameters. That is, given a point source some distance, d1, from a lens focused at distance d2 with focal length l and with a given f/#, there must be an expression for the diameter of the resulting circle of confusion on the image plane. —Ben FrantzDale (talk) 17:29, 26 January 2008 (UTC)

Did you look in circle of confusion or depth of field? You'll find plenty of formulas for different cases, and how to derive them. Dicklyon (talk) 17:47, 26 January 2008 (UTC)