Bokeh affected by distance?

Hey guys, friends are telling me conflicting things about my question...

Scenario 1: I use a 28mm, f2.8 and framed a subject's face to fill half the frame, the other half is background about 20 feet away from subject.

Scenario 2: I use a 200mm, f2.8 and walk back far enough to frame the subject exactly the same, half face half background filling frame.

Which one has more Bokeh?

Assuming you mean more background blur (as bokeh refers to the quality of the out of focus areas so bokeh can be good or bad but not more or less), the longer lens will create more background blur although the DOF for both photos will be very similar. This is because of the narrower AOV (and change in perspective when you moved back) associated with the longer lens.

Both images will have a very similar amount of OOF blur.
This is because:

1. you framed the subject the same way

2. the distance from the subject to the background has remained the same

3. You are using the same aperture

Focal length will not affect the DOF, provided the 3 factors listed above remain unchanged.

fashionrider wrote in post #14980330
Hey guys, friends are telling me conflicting things about my question...

Scenario 1: I use a 28mm, f2.8 and framed a subject's face to fill half the frame, the other half is background about 20 feet away from subject.

Scenario 2: I use a 200mm, f2.8 and walk back far enough to frame the subject exactly the same, half face half background filling frame.

Which one has more Bokeh?

First off, there is no such thing as "more (or less) bokeh". As mentioned above, the term bokeh (as applied to photography in the English language) refers to undefinable qualities of the out-of-focus blur in images. It is not quantifiable.

Secondly - if you moved your camera to keep the framing of the primary subject the same with different focal lengths, the perspective is changed in the images. Perspective is the relative sizes of objects which are at different distances from the camera (or your eye - you can see the perspective change as you move if you're observant). By moving the camera back and using a longer focal length to keep the foreground framing the same, the background objects will appear larger. That, in itself, will change the appearance of the out-of-focus background.

Please read our "sticky" (found in the General Photography Talk forum) tutorial titled Perspective Control in Images - Focal Length or Distance?.

SkipD wrote in post #14981179
First off, there is no such thing as "more (or less) bokeh". As mentioned above, the term bokeh (as applied to photography in the English language) refers to undefinable qualities of the out-of-focus blur in images. It is not quantifiable.

Perhaps there is a such thing as more bokeh, or less bokeh.

If I take an image in which everything in the frame is in sharp focus, there is, by definition, no bokeh, because there is nothing out of focus or blurred.

If I take another image, in which the subject is small in the frame and all of the surroundings are out of focus and blurred, then that image would undoubtedly have more bokeh than the first.

Here are examples; the image of the bark has no bokeh. The image of the Flycatcher has bokeh; in fact, about 70% of the image is bokeh.

According to Wikipedia, bokeh means both the blur and the quality of the blur. There is a point where there is too much blur/magnification at times, especially if you wish to place your subject in a recognizable area. If you are looking only for background separation, then increasing focal length can help you achieve that. Take a look at 35L portraits vs 85L

Tom Reichner wrote in post #14981844
Perhaps there is a such thing as more bokeh, or less bokeh.

Unless it's also possible to describe "how much/many more", "more/less of something" is not a useful statement.

Tom Reichner wrote in post #14981844
Perhaps there is a such thing as more bokeh, or less bokeh.

If I take an image in which everything in the frame is in sharp focus, there is, by definition, no bokeh, because there is nothing out of focus or blurred.

If I take another image, in which the subject is small in the frame and all of the surroundings are out of focus and blurred, then that image would undoubtedly have more bokeh than the first.

Here are examples; the image of the bark has no bokeh. The image of the Flycatcher has bokeh; in fact, about 70% of the image is bokeh.

I don't think the OP or Skip was referring to bokeh in that context. The OP mentioned the same framing and then asked about QUANTITY. The bokeh itself is about QUALITY.

<heavy sigh> It seems that all too many folks now (improperly) use 'bokeh' in the context of referring to the 'out of focus (blurred) background', when in reality 'bokeh' refers to whether the quality of the blurred background is pleasing or displeasing or somewhere in between the two extremes of quality. Bastardization of a term through increasingly common misuse, just as 'prime' lens is bastardization of the real definition of any lens mounted on the body without a supplemental/convertor lens...a 'varible focal length' or 'zoom' lens truly is a 'prime' lens just as much as a fixed focal length lens is also a 'prime' lens! The bastardization is now so prevalent I have almost given up trying to correct the use of 'bokeh' as futile an effort as trying to now correct 'prime'.

The English spelling bokeh was popularized in 1997 in Photo Techniques magazine, when the editor Mike Johnston commissioned three papers about bokeh for the March/April 1997 issue. The May/June 1997 issue of Photo Techniques published three articles on bokeh: “What is Bokeh?” by John Kennerdell; “Notes on the Terminology of Bokeh“ by Oren Grad; and “A Technical view of Bokeh” by Harold Merklinger.

Johnston also altered the anglicized spelling to suggest the correct pronunciation to English speakers. The spellings bokeh and boke have both been in use at least since 1996, when Merklinger had suggested "or Bokeh if you prefer." The Merklinger article can be found on the internet, while the other two articles are not.
In his 1996 article, Merklinger stated, "Japanese apparently refer to the quality of the out-of-focus image as 'bokeh'." Later in the same article he amplifies, "Bokeh, the quality of the out-of-focus image, is determined by the set of brushes: the circles of confusion characteristic of the lens, its aperture and how far out-of-focus it is." © Harold M. Merklinger, Halifax, Canada 1996.

The same issue of Photo Techniques also included an article by Oren Grad. Some of the salient points and terminology from Oren Grad‘s article:

• bokeh refers to the rendition of the out of focus areas of a photograph, and may be classified as good or bad bokeh.
  
• good bokeh softens the objects in front of the plane of focus (mae-boke).
  
• Out-of-focus background objects (ushiro-bokeh) lose detail but maintain their shapes and tones.
  

Wilt wrote in post #14984143
<heavy sigh> It seems that all too many folks now (improperly) use 'bokeh' in the context of referring to the 'out of focus (blurred) background', when in reality 'bokeh' refers to whether the quality of the blurred background is pleasing or displeasing or somewhere in between the two extremes of quality.

Right on, Wilt.
So, if bokeh refers to the quality of the OOF background, and there is no OOF background in an image, then there is no bokeh in that image. There cannot be any quality to something if that something doesn't even exist. You understand that, right?

Tom Reichner wrote in post #14984500
Right on, Wilt.
So, if bokeh refers to the quality of the OOF background, and there is no OOF background in an image, then there is no bokeh in that image. There cannot be any quality to something if that something doesn't even exist. You understand that, right?

There are no OOF areas so the bokeh is unquantifiable.....it'​s not that it doesn't exist, it's just that it can't be evaluated in that image. Bokeh refers to the quality of the OOF areas....it exists as much as "beautiful" or "ugly" exists......That said, I do agree with Wilt in that the general improper use of the word is giving it a new definition.

Tom Reichner wrote in post #14981844
Perhaps there is a such thing as more bokeh, or less bokeh.

If I take an image in which everything in the frame is in sharp focus, there is, by definition, no bokeh, because there is nothing out of focus or blurred.

If I take another image, in which the subject is small in the frame and all of the surroundings are out of focus and blurred, then that image would undoubtedly have more bokeh than the first.

Here are examples; the image of the bark has no bokeh. The image of the Flycatcher has bokeh; in fact, about 70% of the image is bokeh.

The blur is there. You just haven't enlarged it enough. When you do enlarge it enough, you will be able to subjectively evaluate its bokeh.

jra wrote in post #14985319
There are no OOF areas so the bokeh is unquantifiable.....it'​s not that it doesn't exist, it's just that it can't be evaluated in that image. Bokeh refers to the quality of the OOF areas....it exists as much as "beautiful" or "ugly" exists......That said, I do agree with Wilt in that the general improper use of the word is giving it a new definition.

And a lot of people improperly use "cow" to refer to any bovine creature of any age or either gender.

However, people who actually work with cattle need to know the difference between a cow and a bull.

We're actually working with photography.

haha wow thanks for all the info guys.

hmm... another question. With the same scenario with a long lens and a wider one in my original post... which lens would have a narrower DOF?

fashionrider wrote in post #14986903
haha wow thanks for all the info guys.

hmm... another question. With the same scenario with a long lens and a wider one in my original post... which lens would have a narrower DOF?

SkipD's post #4 answers this. If you compare the two shots--the wider and the telephoto--enlarge the wide-angle enough that the background elements are the same size in the display as you see them in the telephoto shots.

You will see that when enlarged to the same display size, the background elements actually have equal "lack of detail" (or rather, the same level of "defocus") in both the wide-angle and the telephoto shots. So the only difference is that they look sharper in the wide-angle shot because they're reproduced smaller.

This is, of course, the same depth of field phenomenon we always see as we enlarge a photograph: The degree of enlargement itself affects the appearance of depth of field in the image. The more the enlargement, the smaller the apparent depth of field.

The telephoto lens provides its own enlargement of the background elements, so we more easily see how blurry they really are at that aperture regardless of focal length.