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Good bokeh? Bad bokeh?

 
 
RichA
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      07-09-2012
On Jul 8, 11:38*am, Pablo <(E-Mail Removed)> wrote:
> I'm confused.
>
> I read this:
>
> <http://www.pentaxforums.com/lensrevi...-Auto-Takumar-...
> F1.8.html>
>
> And take this:
>
> <http://www.flickr.com/photos/wibbleypants/7527964766/in/photostream>
>
> The bokeh seems harsh to me.
>
> Am I doing something wrong?
>
> --
> Pablo
>
> http://www.flickr.com/photos/wibbley...piso/index.php


Be careful what you read into people's reviews of lenses they bought.
They're "reputation" (in their minds) is on the line so if the bought
a dud when it comes to bokeh, they may be reluctant to admit it. I've
got a 58mm f1.4 Voigtlander lens that has awful, jarring-looking bokeh
at f1.4 (even though the lens wasn't really cheap) but stopped down to
f4.0, and it gets really good. Also, the chromatic variant of
spherical aberration plagues these old lens designs (lenses using old
Zeiss designs and old, non-high dispersion glass) is a problem so you
can get defocused colours (red/blue) which will end up visible in edge
detail when light areas meet dark areas. This can cause some odd
results. As can the microlenses used on the camera's sensor itself
and how they interact with the lens on the camera. How much spherical
aberration the lens has also effects bokeh. Note the "imaging
doubling" of the out of focus branches in your shot. Rather than a
smooth blurring, you got that effect.
The thing to do is test. Run the gamut of lens apertures and see what
you come up with, and in what situations. That way, you'll be better
able to predict how a certain shot might look.
 
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Pablo
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      07-09-2012
tony cooper escribió:

> On Sun, 08 Jul 2012 19:54:03 -0400, James Silverton
> <(E-Mail Removed)> wrote:


>>What on earth is "bokeh"? A definition please since I can't find it
>>anywhere else but this ng.C

>
> It's a pretentious word used to describe the appearance of a
> background that is out-of-focus. If you want to be *really*
> pretentious, rave about the "creamy bokeh" your lens produces.


Pretentious it may be, but it works for most people.

The closest the OED gets is:

(yes I know, not in the least related, but scarily close)

Bok globule, n.

Pronunciation: Brit. /bɒk ˈɡlɒbjuːl/ , U.S. /ˌbɑk ˈɡlɑbˌjul/
Etymology: < the name of Bart Jan Bok... (Show More)
Astron.
Categories »

Each of many small interstellar clouds of gas and dust which appear as
dark, roughly circular patches when viewed against a bright background (e.g.
of stars or ionized gas), and which are associated with star formation; =
globule n. 5.
1969 Monthly Notices Royal Astron. Soc. 144 159 The existence of dark
patches seen against many of the diffuse nebulae is well-known... These are
the Bok globules and are due to small absorbing clouds between us and the
nebulae.
1977 Sci. Amer. June 67/2 Bok globules are among the coldest objects in
interstellar space: most are only about 10 degrees Kelvin.
1991 C. A. Ronan Nat. Hist. Universe 192/3 Bok globules..are thought to
be protostar material contracting into stars.
2001 Nature 11 Jan. 140/2 When the eighteenth-century astronomer Sir
William Herschel first encountered a Bok globule in his telescope, he
exclaimed: ‘Mein Gott, da ist ein Loch in Himmel’ (‘My God, there is a hole
in the skies’).


> Some people use it incorrectly to describe a background that is
> out-of-focus (as intended) due to a shallow depth-of-fied.


When I've criticised people for using the word 'gender' to describe
somebody's sex, I've been shot down for not accepting that meanings change.
Obvious examples being 'gay' and now, it would seem, 'bokeh'.

In my adopted language, it's a bit easier; they say 'desenfoque' for
anything intentionally OoF. I suppose we could just say 'blurred'.

--
Pablo

http://www.flickr.com/photos/wibbleypants/
http://paulc.es/piso/index.php
 
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Chris Malcolm
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      07-09-2012
tony cooper <(E-Mail Removed)> wrote:
> On Sun, 08 Jul 2012 19:54:03 -0400, James Silverton
> <(E-Mail Removed)> wrote:
>>On 7/8/2012 7:47 PM, PeterN wrote:
>>> On 7/8/2012 3:42 PM, Savageduck wrote:
>>>> On 2012-07-08 12:15:08 -0700, tony cooper <(E-Mail Removed)>
>>>> said:


>>>>> On Sun, 08 Jul 2012 17:38:10 +0200, Pablo <(E-Mail Removed)> wrote:
>>>>>
>>>>>> I'm confused.
>>>>>>
>>>>>> I read this:
>>>>>>
>>>>>> <http://www.pentaxforums.com/lensrevi...-Takumar-55mm-
>>>>>>
>>>>>>
>>>>>> F1.8.html>
>>>>>>
>>>>>> And take this:
>>>>>>
>>>>>> <http://www.flickr.com/photos/wibbleypants/7527964766/in/photostream>
>>>>>>
>>>>>> The bokeh seems harsh to me.
>>>>>>
>>>>>> Am I doing something wrong?


All you can do with the bokeh of particular lens is to increase or
decrease the amount of blurring, you can't change the character of the
bokeh. (Unless it's one of those specialised lenses with bokeh controls.)

>>>>> "Bokeh" is just what is in the background that is out-of-focus. Your
>>>>> background is out-of-focus. Just what you want.
>>>>
>>>> Pablo wants the shallow DOF, but not so shallow that the entire texture
>>>> of the tree is not captured in detail. As a result his exposure settings
>>>> are a compromise. The cost of that compromise is, the background is not
>>>> as OOF as he anticipated.
>>>>
>>>>> The ugliness of the background is the mottled purplish color. The
>>>>> green's fine, but there's something in the background that is blue or
>>>>> purple that looks kinda ugly here. It's the color, not the bokeh,
>>>>> that is the problem.
>>>>
>>>> I could be wrong, but I suspect the background is a vineyard, and what
>>>> you ID as "mottled purplish color" is soil and part of the vine trellis
>>>> work.
>>>>
>>>>> That same shot, with the same settings, but with a different foliage
>>>>> in the background would be what you wanted to achieve.
>>>>
>>>> I have a feeling that is easier said than done. Perhaps at a different
>>>> time of year?
>>>>
>>>>> There's some things you can do if you have Photoshop, but I'm not
>>>>> going to spend time explaining how if you don't have Photoshop. Any
>>>>> version, including Elements 9 or 10, with Replace Color or Match Color
>>>>> and Layer Masking will work.
>>>>
>>>> Yup!
>>>
>>> He can also make a rough selection, invert and feather it. then apply
>>> either a Gaussian, or surface blur to taste.
>>>

>>What on earth is "bokeh"? A definition please since I can't find it
>>anywhere else but this ng.C


> It's a pretentious word used to describe the appearance of a
> background that is out-of-focus. If you want to be *really*
> pretentious, rave about the "creamy bokeh" your lens produces.


> Chase down "bokeh" with Google and you will find it comes from the
> Japanese word "boke", which means "blur" or "haze". The "h" was added
> to make the word approximate the Japanese pronunciation of "boke".


> It's also a word that is misused more than it is correctly used. Used
> correctly, it describes the appearance of specular highlights in the
> background...the light shining off a leaf, for example. The whole
> leaf is out-of-focus, but the spot of light reflected is the "bokeh".


> Some people use it incorrectly to describe a background that is
> out-of-focus (as intended) due to a shallow depth-of-fied.


I tend rather to agree with the Wiki article on bokeh, which suggests
that some people incorrectly describe it as the appearance of out of
focus specular highlights. The appearance of these highlights is the
simplest and easiest way to see the basic character of the bokeh of a
particular lens, but it is not restricted to the appearance of those
highlights. You can have harsh ugly bokeh without any highlights in
the image.

For example, the kind of poorly corrected spherical aberration at wide
apertures which gives a brighter edge than centre to OOF highlights
will do the same to all high contrast edges, just less obviously. In
the case of long thin things like blades of grass or plant stems it
will give rise to a doubled image appearance. The most extreme form of
this is seen in the notorious "doughnut" bokeh of reflex lenses, which
have a doughnut shaped aperture.

An optically perfect lens would turn OOF point light sources into
evenly lit sharp edged images of the iris shape, usually an
approximate circle, such as a hexagon. Hence the "doughnut" bokeh of
the reflex lenses with their fixed aperture and central mirror
obstruction. Hence the bokeh trick of making your own auxiliary iris
of a cute shape, like a heart shape, and photographing lots of tiny
lights with it, like Xmas tree lights.

Odd numbers of iris blades reduce corner diffraction effects on bright
lights. Curved iris blades and more of them make it more like a
circle. Prime numbers are best because there's never any diametrical
coincidence of two corners. So the best iris blades have a prime
number of curved blades, the more the better.

There remains the problem of the sharp aperture edge. The ideal
"smooth creamy" bokeh is produced by a soft blurred edge to OOF
highlights. That's usually achieved (by accident or design) by leaving
some natural optical defects of the lens incompletely corrected. You
get nicer bokeh at the cost of less microcontrast of the sharply
focused parts, which inevitably means a softer image with some loss of
low contrast detail.

Spherical aberration gives asymmetrical bokeh on either side of sharp
focus. OOF near objects will have harder edged bokeh, and OOF distant
objects softer, or vice versa. So some specialised bokeh control
lenses allow you to shift the poorer bokeh in front or behind, and
also permit less compromise of in focus microcontrast and
detail. Sony's (Minolta's) STF lens is the bokeh king, using an
apodising iris filter to give very smoothly graded bokeh with no
visible edges without any compromise to in focus sharp detail. The
cost is about two stops of light transmission.

Do you have to wear spectacles? If so, take them off and examine the
bokeh of your eyes by looking at a small bright light source. The
bokeh of mine is disgusting!

--
Chris Malcolm
 
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James Silverton
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      07-09-2012
On 7/8/2012 8:31 PM, Savageduck wrote:
> On 2012-07-08 16:54:03 -0700, James Silverton
> <(E-Mail Removed)> said:
>
> <<< Le Snip >>>
>
>> What on earth is "bokeh"? A definition please since I can't find it
>> anywhere else but this ng.C

>
> Then you haven't been looking very hard, next time try Google.
> If you had been following this thread you would have found Tony Cooper's
> contribution.
>
> < http://en.wikipedia.org/wiki/Bokeh >
>
>

Marvelous! I can't see any real use for it *to me* and I would have
wished Tony had coined his word from Latin or Greek which might have
allowed me to deduce its meaning. "Bokeh" is not in the OED nor even
recognized by the Thunderbird spell checker.

--
Jim Silverton (Potomac, MD)

Extraneous "not" in Reply To.


 
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Pablo
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      07-09-2012
Floyd L. Davidson escribió:

> If you would like, I can post links to two edited variations on
> your image. They both have the same processing, and the second
> is also cropped to a 5:4 aspect ratio, which I like better. The
> foreground has been sharpened. The background has been
> selectively (meaning by different amounts in different places)
> blurred, darkened, and the contrast reduced. It was all done
> with GIMP.
>
> It makes for a much more dramatic image. But I won't post it
> without your permission.


Post away. I posted the link to ask for advice - it's no work of art of
which I'm proud

--
Pablo

http://www.flickr.com/photos/wibbleypants/
http://paulc.es/piso/index.php
 
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Pablo
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      07-09-2012
Floyd L. Davidson escribió:


> Look down in the lower left corner, where there are three
> different objects, probably tree trunks, that are more or less
> vertical and more or less white. Notice that each of them
> appears as an out of focus double object, with a "ghost" offset
> horizontally. That is probably caused by a combination of an
> over correction for spherical aberrations and an astigmatism.
> It contributes to what will generally be a relatively harsh
> bokeh in areas with many bright vertical lines. An example
> would be a background of grass in bright sunlight.
>
> Other than that, the harsh bokeh of your image is not a product
> of the lens so much as it is the high contrast between the
> background and the subject. I don't see changing the color as
> at all significant. Anything bright with even minimal detail is
> not going to help.


One point: I just remembered that I forgot to attach the hood for that shot.
It was a very bright day, with the sun directly overhead (as is often the
case here).

Might this have had an adverse effect?

--
Pablo

http://www.flickr.com/photos/wibbleypants/
http://paulc.es/piso/index.php
 
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Martin Brown
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      07-09-2012
On 09/07/2012 13:21, James Silverton wrote:
> On 7/8/2012 8:31 PM, Savageduck wrote:
>> On 2012-07-08 16:54:03 -0700, James Silverton
>> <(E-Mail Removed)> said:
>>
>> <<< Le Snip >>>
>>
>>> What on earth is "bokeh"? A definition please since I can't find it
>>> anywhere else but this ng.C

>>
>> Then you haven't been looking very hard, next time try Google.
>> If you had been following this thread you would have found Tony Cooper's
>> contribution.
>>
>> < http://en.wikipedia.org/wiki/Bokeh >
>>
>>

> Marvelous! I can't see any real use for it *to me* and I would have
> wished Tony had coined his word from Latin or Greek which might have
> allowed me to deduce its meaning. "Bokeh" is not in the OED nor even
> recognized by the Thunderbird spell checker.


The word originally came from the Japanese where it is "boke" two
syllables with a final e that is not silent. The "h" was added to get
Westerners pronunciation to approximate that of the original word.

It is use to qualitatively describe the characteristic PSF of the lens
in parts of the image that are out of focus.

A good lens degrades gracefully with at worst a uniform circular (or
strictly aperture stop shaped) blur - some specialist lenses are
designed to control this.

A bad lens has a sharp outer ring and a mirror lens a characteristic
donut centre. These tend to detracts from nice smooth background blurs.

You can most easily see the effect of bokeh on out of focus highlights.

A few samples (look at the highlight on the glass behind the bottle).

http://www.rickdenney.com/bokeh_test.htm

I don't entirely agree with his subjective distracting / pleasing
assessment. The Sonnar isn't all that appealing to me despite being
almost uniform (and the B+L Tessar and Biometar are downright ugly).


--
Regards,
Martin Brown
 
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tony cooper
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      07-09-2012
On Mon, 09 Jul 2012 03:35:21 -0800, http://www.velocityreviews.com/forums/(E-Mail Removed) (Floyd L.
Davidson) wrote:

>Pablo <(E-Mail Removed)> wrote:
>>tony cooper escribió:
>>> On Sun, 08 Jul 2012 19:54:03 -0400, James Silverton
>>> <(E-Mail Removed)> wrote:

>>
>>>>What on earth is "bokeh"? A definition please since I can't find it
>>>>anywhere else but this ng.C

>
>Bokeh is the *quality* or *character* of out of focus areas.
>
>>> It's a pretentious word used to describe the appearance of a
>>> background that is out-of-focus. If you want to be *really*
>>> pretentious, rave about the "creamy bokeh" your lens produces.

>>
>>Pretentious it may be, but it works for most people.

>
>It is not in any way pretentious. For example, "creamy bokeh"
>is a very correct usage, and might be accurate (but not for your
>image). Saying that an image "has great bokeh" is almost
>meaningless, saying that it has "a lot of bokeh" is totally
>meaningless. If it has any area that is not in focus, bokeh is
>the quality of that area. It might be harsh, it might be
>smooth, it might be pleasing, or it might be annoying. It
>cannot be more or less though...
>
>>The closest the OED gets is:

>
>QED's closest has nothing to do with a word that essentially is
>what we call a "term of art",


I know it gets your bowels in an uproar when one of your spelling
errors is flamed, but this one deserves to be commented on if only for
irony involved.

Now, protest vehemently with your usual inclusion of insults so I
can reply: QED - quod erat demonstrandum.


--
Tony Cooper - Orlando, Florida
 
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tony cooper
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      07-09-2012
On Mon, 09 Jul 2012 03:35:21 -0800, (E-Mail Removed) (Floyd L.
Davidson) wrote:

>>> Some people use it incorrectly to describe a background that is
>>> out-of-focus (as intended) due to a shallow depth-of-fied.

>
>That is *exactly* what it is *properly* used for.
>

No it isn't. It is properly used to describe certain aspects of a
background that is out-of-focus (as intended), but not a background
that is out-of-focus (as intended) where those aspects are not
present.

The "background" is simply that: the area of the photograph behind
the subject. A photograph of a subject with a brick wall behind them
may have been taken with the settings that present the wall as
blurred, indistinct, and with the edges of the bricks undefined. Good
treatment, but not good bokeh.


--
Tony Cooper - Orlando, Florida
 
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James Silverton
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      07-09-2012
On 7/9/2012 9:12 AM, Savageduck wrote:
> On 2012-07-09 05:21:51 -0700, James Silverton
> <(E-Mail Removed)> said:
>
>> On 7/8/2012 8:31 PM, Savageduck wrote:
>>> On 2012-07-08 16:54:03 -0700, James Silverton
>>> <(E-Mail Removed)> said:
>>>
>>> <<< Le Snip >>>
>>>
>>>> What on earth is "bokeh"? A definition please since I can't find it
>>>> anywhere else but this ng.C
>>>
>>> Then you haven't been looking very hard, next time try Google.
>>> If you had been following this thread you would have found Tony Cooper's
>>> contribution.
>>>
>>> < http://en.wikipedia.org/wiki/Bokeh >
>>>
>>>

>> Marvelous! I can't see any real use for it *to me* and I would have
>> wished Tony had coined his word from Latin or Greek which might have
>> allowed me to deduce its meaning. "Bokeh" is not in the OED nor even
>> recognized by the Thunderbird spell checker.

>
> If at anytime you might want to describe the characteristics of a
> particular lens with regard to the OOF areas due to shallow DOF, you
> might well see a real use for the word "bokeh".
>
> "Bokeh" is certainly not a word Tony "coined".
>
> As for using Latin or Greek origins to formulate a word so that you
> could deduce its meaning, you might consider that contemporary English
> has many words with origins further afield than Latin or Greek, ranging
> from Afrikaans, Arabic, through Hindi, and Japanese to Zulu.
>
> "Bokeh" has been part of the photography lexicon since at least 1998.
> Information you might have gleaned if you read and comprehended the
> Wikipedia article.
>
> Regarding OED, you might want to update the edition you are using.
> < http://oxforddictionaries.com/definition/english/bokeh >
>
> ...and you seriously have complete faith in a Windows, or
> Mozilla/Thunderbird spell checker?
>

No, I sometimes disagree with any spell checkers but they *are* an
indication of usage. My OED is the up-to-date online version available
via my public library. To me "bokeh" sounds like something dreamed up by
the pretentious Hyacinth Bucket of British TV.

--
Jim Silverton (Potomac, MD)

Extraneous "not" in Reply To.


 
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