Originally posted by eddie1960 your definition of Bokeh is too narrow, it includes the highlights - at least as far as wiki is concerned
from the wiki
Bokeh Quote: Since any image is represented by a large number of images of points, we may attempt to understand the whole by considering the blurring of a single point. An unsharply imaged point is associated with a circle of confusion, or a blur disk. This blur disk is characterized by
- A size.
- A shape.
- The light distribution across the disk.
The size of the disk determines the "amount of blur". The shape of the blur patch does not need to be circular, in which case the designations "circle of confusion" or "blur disk" are misnomers. Nonetheless, for convenience the word disk will be freely used to mean a patch of arbitrary shape. Although the size and the shape of the disk are unmistakable blur characteristics, they do not touch the essence of bokeh as the Japanese intended the word. The distribution of light across the disk does. However, the distinction is not always clear and what follows is intended as an overview of a variety of factors that influence the rendering of OOF image parts. Explanations of the underlying mechanisms will be brief and the reader is referred to other pages for elaborateness.
About Bokeh Quote: The rest of the misconceptions are right to a certain degree, but there is more to the story of “lens bokeh.” To start with, people who think that caring about Bokeh is just photographic elitism are slightly off base, in my opinion. It is true that people who do only wide sweeping landscape photography hardly need to worry about Bokeh-- the important thing for them is a lens that is razor sharp at higher apertures, and they usually don’t want ANYTHING out of focus. But with portrait pictures, flower pictures, macro pictures and when you want to make a subject really pop out of the picture, one will have a significant portion of the picture that is out of focus. Why would one think that this wide swath of film area doesn’t matter? A sharply focussed and busy background often detracts from the image, drawing your attention away from the subject (see the image on the introduction page for an example). An image with bad bokeh does the same, making a busy background out of what should have been smoothly rendered background that would make your subject stand out. Furthermore, the shape of aperture blades DOES make a difference to the bokeh of a picture, but only in that non-circular aperture blades will lead to non-circular highlight out of focus “circles.” This should mostly affect single specular points of light in the background, while the effect on solid shapes and lines should be minimal. There is far more to the quality of blurred areas in images than simply the circularity of the aperture blades. It also has to do with the path of light through the lens elements, how well corrected the spherical aberration is, as well as coma, curvature of field, astigmatism and a few other properties of lenses. At this time, I am focusing on Spherical aberration, since this appears to have probably the most effect on “lens bokeh.” As this site develops I may expand to other lens parameters which affect bokeh, as well.
http://www.zeiss.com/c12567a8003b8b6f/embedtitelintern/cln_35_bokeh_en/$file/cln35_bokeh_en.pdf
Quote: Sometimes the phenomenon of the individual iris images is equated with “bokeh’; under this heading one finds collections of pictures in which iris images are mixed with photos of soap bubbles. But this is not what is meant by “bokeh”. In the iris image the lens is reading the cards to a certain extent but what significance has all this for the reproduction of image areas in which there are no highlight areas?
Quote: There is a particularly interesting point further to the left in the graphic above, about 0.4 mm in front of the focal point of the paraxial rays: there, the marginal rays seem to overtake those travelling more on the inside. The light cone is no longer ideally arranged, and we could say that the rays of light are "confused."
This is the original meaning of the Japanese word "bokeh."
http://www.kenrockwell.com/tech/bokeh.htm Quote: Diaphragm Blades
The shape and number of a lens' diaphragm blades has little to do with bokeh. They define the shape of the blur circle, but they don't define how the light is distributed within that circle. These circles are no longer circles, but shapes with as many sides as there are blades. For instance, with five blades as most Hasselblad and Mamiya lenses one gets five-sided pentagons as the shapes of out-of-focus highlights instead of circles. This isn't too great. With six blades, most common in discount lenses for 35mm SLRs, one gets hexagons. With seven blades (most Nikkor SLR lenses) things really start to improve, since the seven-sided heptagons start looking like circles instead of recognizable shapes. Nine blades (common on Nikkor telephotos) are great, and lately they are being designed with curved blades to give a close approximation of a circle.
Odd numbers of blades will give diffraction and reflection stars around very bright points of light that have double the number of points as the number of blades. For instance, a seven-blade diaphragm will give a lovely 14-pointed star. Even numbers of blades will give stars with the same number of points as you have blades. An eight-bladed diaphragm will give a boring eight pointed star.
Again, how well one approximates a circle is only a small part of the equation. The important part is how the light is distributed. Obviously at full aperture where most people worry about this the diaphragm plays no part.
The reason some manufacturers attempt to draw a correlation between bokeh and numbers of diaphragm blades is because it's easy to see how many blades there are at the sales counter, but almost impossible to see bokeh.
http://jtra.cz/stuff/essays/bokeh/ Quote: The character of bokeh is best observed on small light sources. This character is mainly given by optical construction of lens. Most of modern lenses have rounded aperture blades. Older straight aperture blades produced polygonal out of focus highlights (if aperture was slightly closed). While the aperture blades are rounded in current lenses they may still be slightly visible in some aperture settings. Sometimes a single blade is slightly misaligned and more visible than others. I have seen too often marketing claim "rounded aperture blades produce pleasing bokeh". But rounded aperture blades are not guarantee of pleasing bokeh.
Originally posted by creampuff I think the onus is on you to prove your point since it is you who is making claims that rounded highlights isn't bokeh. Suffice to say my understanding of bokeh relates to the way a lens renders out-of-focus points of light and rounded aperture blades do make a difference small as they may be.
And btw, irrespective whether posting other people's images is beneficial or constitutes free advertising doesn't change the fact that you didn't even bother to seek permission or credit the person. Talk about bad form when you can't even come up comparative images of your own to back up your assertions.
You can find explanation above as for the rest, we live in a society that you need to prove that something is, so rather that i need to prove that highlights isn't bokeh you need to prove it is.
Beside i've offered to do it if you or anyone else will borrow me their DA40XS, it's unreasonable for you to suggest i need to buy a DA40XS just to prove my point and since you have both the XS and the limited it's easier for you to prove you're right.
Like i said i'm happy to provide images if i've access to lenses that can be used for such a comparison.
And i linked to the person site, you can see his name, contact information and the rest of his photos there.
Really this goes about nothing, if you don't want that people see your images on the internet then don't put them there publicly.
ps. about bokeh and the blurriness you should really read the Carl Zeiss PDF, it has all the information.
http://www.zeiss.com/c12567a8003b8b6f/embedtitelintern/cln_35_bokeh_en/$file/cln35_bokeh_en.pdf