bokeh

[Ed_Davor]

Hi

this is not limited to 35mm photography but I can't see a separate forum for lenses, so I'll post here, but it's NOT tied to 35mm

Anyway, as far as I know, there are two kinds of distortions from "correct" bokeh, which is supose to be when lights make uniform circles..
One is when you get regular smooth blur where light sources are stronger in the middle and fade towards edges of the circle.
The other is reversal of this, when the light sources appear weak in the middle.

so I have a few questions about that:

Can someone show me an example of the third kind of bokeh (the one where you get lights with dim centers, the "negative" bokeh)?
And also, I'd like to ask you people, which do you prefer of these 3 types of bohek yourself and why?

[elekm]

Originally Posted by Ed_Davor

... the third kind of bokeh -- the one where you get lights with dim centers, the "negative" bokeh

I think I experienced this once after several shots of tequila.

[narsuitus]

Ed,

I don’t understand the difference between your second and third examples. They seem the same to me.

Where does the donut hole bokeh that is formed by mirror lenses fit among your three examples?

Do you have published references for the three types of bokeh you listed? I would like to obtain some additional information.

[Ed_Davor]

One is when you get regular smooth blur where light sources are stronger in the middle and fade towards edges of the circle.
The other is reversal of this, when the light sources appear weak in the middle.

this is the second and the third...

the third is like when you invert the second

but anyway, I'm the one trying to learn something here, so you tell me

what is donut hole bohek?


here are the examples of the 3 boheks I was talking about, not in the same order though, the one I'm interested in is the first one in the list on that site (the one with the hole in the middle of the object trace)

http://www.kenrockwell.com/tech/bokeh.htm

[Ole]

The "bright edge bokeh" is a result of overcorrected spherical aberration. It's very common in the foreground blur from long telephoto lenses, since these tent t be designed for smooth blurry backgrounds.

"Bright center" is undercorrected spherical aberration. Often introduced on purpose, for extra smooth backgrounds - see above.

"Donut" is what you get from catadioptric (mirror) lenses.

Here's an example of different foreground and background bokeh, foreground on the left and background on the right in this example. Just having fun with swings, and a big fast lens: 300mm f:4.5 Xenar, at f:4.5 on 5x7" film:

[Ed_Davor]

thanks, by the way, how is bokeh pronaunced?

[rbarker]

Bokeh = boh-kay

[Oren Grad]

Originally Posted by rbarker

Bokeh = boh-kay

No. The sound is a short "e" (as in "let", or "beg"), not a long "a" (as in "pay" or "hay"). Americans sometimes find this strange, since short "e" as an ending sound is not common in English. But it's very common in Japanese.

I transliterated it from Japanese as "boke", but when he ran the feature articles in Photo Techniques, Mike Johnston added the "h" to keep people from pronouncing it to rhyme with "Coke".

Cheers...

[firecracker]

Originally Posted by Oren Grad

No. The sound is a short "e" (as in "let", or "beg"), not a long "a" (as in "pay" or "hay"). Americans sometimes find this strange, since short "e" as an ending sound is not common in English. But it's very common in Japanese.

That's right.

[donbga]

Originally Posted by Oren Grad

No. The sound is a short "e" (as in "let", or "beg"), not a long "a" (as in "pay" or "hay"). Americans sometimes find this strange, since short "e" as an ending sound is not common in English. But it's very common in Japanese.

I transliterated it from Japanese as "boke", but when he ran the feature articles in Photo Techniques, Mike Johnston added the "h" to keep people from pronouncing it to rhyme with "Coke".

Cheers...

So in plain English, bokeh should be pronounced, BO - KEY?