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Question

WendyBoatcomesin
Posted 27/06/2009 - 20:51 Link
I keep reading the term 'bokeh', I don't wish to sound daft, but wassit mean?


Serious answers / mickey taking all recieved gratefully.

Ta.
K10D
MZ-50
ME Super
Edited by WendyBoatcomesin: 27/06/2009 - 20:52
johnriley
Posted 27/06/2009 - 20:56 Link
It's a relatively new term that refers to the appearance of the out of focus areas in an image. Technically, the number of leaves in the diaphragm in the lens will affect bokeh, generally more leaves equating with a smoother look.

I get the feeling that sometimes it's referred to as being much more objective as a description than it really is.
Best regards, John
Anvh
Posted 27/06/2009 - 21:51 Link
Here is a read link
As you can read John proves he is also human because he is not right for once
Bokeh isn't effect by the number of blades since that only defines the shape of the blur circle but not the distribution of the light in that circle and that's what bokeh is all about.
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Edited by Anvh: 27/06/2009 - 21:56
Malo1961
Posted 27/06/2009 - 22:35 Link
Here you have an example of smooth bokeh. Just look at the blurred daisy's in the background.
It was shot wide open with the SMC K 1.8/55. In-Focus area was razor thin, just at the tip of the birds metal beak.

Comment Image


The way bokeh appeals to the human eye, is still (despite countless discussions) a very subjective matter.

Martin.
Best regards,

Martin.


Curious about my photography?? Just Follow the Light.
Anvh
Posted 27/06/2009 - 22:43 Link
Malo1961 wrote:
The way bokeh appeals to the human eye, is still (despite countless discussions) a very subjective matter.

Martin.

Not really Martin, good it isn't always black and white but some lenses clearly have a better bokeh then others.

From here link

Fig. 1. Poor Bokeh.
Comment Image

This is a greatly magnified blur circle showing very poor bokeh. A blur circle is how an out-of-focus point of light is rendered. Note how the edge is sharply defined and even emphasized for a point that is supposed to be out-of-focus, and that the center is dim.

Fig 2. Neutral Bokeh.
Comment Image

This is a a technically perfect and evenly illuminated blur circle. This isn't good either for bokeh, because the edge is still well defined. Out-of-focus objects, either points of light or lines, can effectively create reasonably sharp lines in the image due to the edges of the sharp blur circle. This is the blur circle from most modern lenses designed to be "perfect."

Fig. 3. Good Bokeh.
Comment Image

Here is what we want. This is great for bokeh since the edge is completely undefined. This also is the result of the same spherical aberration, but in the opposite direction, of the poor example seen in Fig. 1. This is where art and engineering start to diverge, since the better looking image is the result of an imperfection. Perfect bokeh demands a Gaussian blur circle distribution, and lenses are designed for the neutral example shown in 2.) above.
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
johnriley
Posted 27/06/2009 - 22:56 Link
I've mixed feelings about the article linked to, as it says some pretty dubious things, many of which would be hard to prove or disprove.

Although I can see what is being got at, I'm not convinced that we really have a set of rules that we can apply that describe bokeh. I've seen some horrible effects in out of focus backgrounds that the photographer has described as wonderful bokeh, so there may be a lot of imperfect understanding.

Martin's image doesn't fall into that category, but I still don't find all those discs appealing, so I'll go along with it all being subjective.
Best regards, John
Malo1961
Posted 27/06/2009 - 23:02 Link
Still....,what is considered good or bad remains subjective. I have seen examples of bokeh fitting your nr. 1 figure.
Small multi coloured lights hanging in a street scene by night. And IMO it looked fantastic.
It depends a lot on the subject itself. Bokeh can look very weird, even impressionistic or painterly. It's all a matter of personal taste in the end.

I'll give you one thing. And that's the comment in fig.3. It's commonly accepted that the older lens designs with lot's of blades
are capable of producing the smoothest bokeh.

Martin.
Best regards,

Martin.


Curious about my photography?? Just Follow the Light.
johnriley
Posted 27/06/2009 - 23:11 Link
Some old lenses, and I mean old brass lenses in the main, have an amazing number of blades and give a virtually circular aperture. This is sometimes found in lenses for miniature cameras (medium format and 35mm in this context)up to the 1960s.

There's nothing quite like these for DSLRs though.
Best regards, John
Malo1961
Posted 27/06/2009 - 23:20 Link
johnriley wrote:
Some old lenses, and I mean old brass lenses in the main, have an amazing number of blades and give a virtually circular aperture. This is sometimes found in lenses for miniature cameras (medium format and 35mm in this context)up to the 1960s.

There's nothing quite like these for DSLRs though.

Actually....there is. May I introduce the Bokeh Monster ? Just buy the genuine PK to M42 adapter and you are rolling.

Martin.

135 MM/f2,8 and 15 blades. Image that.....
Best regards,

Martin.


Curious about my photography?? Just Follow the Light.
Anvh
Posted 27/06/2009 - 23:37 Link
Martin, who said that a poor bokeh is bad for a photo???
Sometimes a poor bokeh is fitted for certain photos and sometimes not, that's subjective. If the bokeh is fitted for the photo or not but not the quality of the bokeh.

And that's the comment in fig.3. It's commonly accepted that the older lens designs with lot's of blades
are capable of producing the smoothest bokeh.

No it doesn't say that, what has number of blade to do with distribution of the light???
Certainly wide open all apertures are round regardless the number of blades
(from below Luminous landscape: Whether a lens exhibits the 'bright ring' or 'bright core' circle of confusion depends upon the details of how the spherical aberration is corrected.)

Wikipedia link
Bokeh characteristics may be quantified by examining the image's circle of confusion. In out-of-focus areas, each point of light becomes an image of the aperture, generally a more or less round disc. Depending how a lens is corrected for spherical aberration, the disc may be uniformly illuminated, brighter near the edge, or brighter near the center. Lenses that are poorly corrected for spherical aberration will show one kind of disc for out-of-focus points in front of the plane of focus, and a different kind for points behind. This may actually be desirable, as blur circles that are dimmer near the edges produce less-defined shapes which blend smoothly with the surrounding image.

luminous-landscape link
The 'bright ring' effect is what I suggest leads to 'bad boke' and especially 'ni-sen'. The 'bright ring' type circle of confusion allows some aspects of detail in the original scene to show up in out of focus areas and even to be replicated. An extreme example of the 'bright ring' circle of confusion is that produced by a typical mirror lens. Figure 10, by Kevin Hawk, shows a background out-of-focus spire as a very distinct double image.

The 'bright core' type circle of confusion is observed with the 35/2 Summicron on both sides of the point of focus. I suggest the bright core circle of confusion leads to pleasant out-of-focus images, provided the core is not too strongly concentrated. If the central bright core is too small, again some fine detail is painted into out-of-focus areas — although at least it is not replicated.

It would be an over simplification to say that normal spherical aberration (as for the Imagon) leads to 'good boke' while over-corrected spherical aberration leads to 'bad boke', but it is probably true that out-of-focus backgrounds are more likely to be encountered and are potentially more disturbing than out-of-focus foregrounds.

Whether a lens exhibits the 'bright ring' or 'bright core' circle of confusion depends upon the details of how the spherical aberration is corrected.
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Edited by Anvh: 27/06/2009 - 23:39
iceblinker
Posted 27/06/2009 - 23:38 Link
WendyBoatcomesin wrote:
I keep reading the term 'bokeh', I don't wish to sound daft, but wassit mean?

Some people use it to mean specifically out of focus highlights, others just to mean everything that is out of focus. It's easier to see differences for the former between one lens and another (when all else is equal), not so much for the latter, and frankly I think a lot of the perceptions for the latter are just from imagination or not comparing like with like.
~Pete
mikew
Posted 28/06/2009 - 07:23 Link
Just as an aside I have looked at a 90mm Elmar I have in the drawer and that at a rough count has well in excess of 20 blades. When I was using it 30 years ago (and it was old then) we didn't seem to talk about Bokeh just good lenses. I wonder if this in part gave Leica lenses their reputation for quality? I must see if I can find a couple of old photos and look at the OOF areas.

Mike
---------------------------------------------------

You can see some of my shots at my Flickr account.
gartmore
Posted 28/06/2009 - 11:59 Link
I understand the Japanese word is roughly translated as 'chaos' - seems appropriate somehow!
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -
greynolds999
Posted 28/06/2009 - 13:57 Link
And to be very subjective...

I struggle to find an example, but I always felt that no matter how good the quality of a mirror lens, the little bokeh rings they produced were too distracting to ever look good.
johnriley
Posted 28/06/2009 - 15:28 Link
Perhaps "bokeh" is what used to be referred to as "plasticity", a quality attributed to German lenses. Japanese ones were regarded as contrastier, sharper, but lacking that indefinable quality.
Best regards, John

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