Definition of bokeh, simply gibberish?

Started Mar 6, 2014 | Discussions thread
OP guitarjeff Senior Member • Posts: 1,165
Re: how would you measure blur?

tko wrote:

Do you know what blur is? How would you measure it? What tests? Giving a photo, could you analyze the background blur?

Analyze it for what? I know that blur caused by camera shake has a unique preperty in that all the photo is blurred.  If the subject is blurred but not any other items in the frame are blur this would imply subject movement and not camera shake.  I think it's fairly easy to see when it is due to dof and due to camera shake or subject movement, but I'll go wit it and see where you are headed.

So, assuming the answer is no, blur is controversally term that doesn't mean anything because we can't measure it.

I am not sure at all that it cannot be measured.  It can when talking abut dof, and i would thing experts could measure how far a subject moved to get the specific amount of blur compared to shutter seed and such.  This all seems vague at the moment, I'll keep reading.

guitarjeff wrote:

tko wrote:

So, do we go around throwing out every word in the dictionary that isn't defined by measurable parameters?

Why would you do that?

Happy? Pretty? Sad, beautiful, sexy, good, evil, right, wrong, fun, art. A great photo, an artistic photo, a pretty photo.

Nothing wrong at all with the dictionary explaining terms which are subjective. If I feel a certain way but don't know what to call it, one of these explanations might help me understand a word that might better describe it. All words in the dictionary need not define ACTUAL things or phenomenon.

None of these are measurable, yet we all pretty much know what they mean, and use them everyday with no controversy.

Yep, no need for controversy.

Bokeh is very well defined.

Yep, and the only rational definition is "blur in a photo due to a dof that doesn't encompass the entire frame." Saying it is THE QUALITY of blur is meaningless nonsense.

Not only it how out of focus the background is, but it is how smooth and pleasing the transitions are.

You mean how smooth the BLUR is. Whether it's pleasing or not is completely subjective.

So, the quality of the composition, the quality of the exposure, the quality of the color balance, are all meaningless terms since quality hasn't been defined? After all, composition is all subjective.

Again we are confusing two different meanings for the word quality.   The way you are using it is the type where I say, to me, that painting is a quality work of art.  That meaning of quality is COMPLETELY subjective.   But the other meaning is to use it as a description of certain aspects of a thing or phenomenon.  In that usage, your statement is false.  It would not be meaningless because i can describe several qualities to each of the thongs you mention.  I can say the color has the quality of being saturated or not, that it has the quality of having low noice, the quality of having a large field of view.   Those are not meaningless uses of the word quality while the other is completely subjective.   Now, you could say Saturation, large field of view is also subjective and that's true, but I could also say the quality of having or nbot having blown out highlights.  That would not be subjective because either you have a blown highlight or you don't.  So yeah, there are two ways to use the word quality.

I'm sure if someone was bored enough they could come up w/a way of measuring the blur quality.

Really? I would love to see that.

Smoothness, roundness, fall off versus distance, error from an ideal, radially symmetrical Gaussian drop off from a point source. Easy peasy.

That does not measure quality in the second sense, as that is subjective, and in the first sense, you are simply describing the qualities it has and measuring them as if I were telling you that my table has the quality of having 90 degree angles and then we measure them to prove it.  So that's no big deal.  I meant i want to see the first meaning measured, because it can't be.

Can you even define blur? Most people can't, even though they intuitively know what it means. How would YOU measure blur?

See above where i spoke of this.

I could measure blur, and I could measure blur quality.

You can measure aspects of the blur that are qualities of it (the quality of the 90 degree angle my table has).  You cannot measure the entirety of the quality of blur, that would be the same as saying the guy that finds the painting to be a quality work can measure what that quality is and demonstrate it as fact to others.  that is subjective and cannot be measured.

It really isn't that hard, and anyone can see the difference with their eyes. Both a equally easy to measure.

That's all fine, but where are you going with this?

I'm always amazed when newbies step and try to redesign words that have been in common use for years.

Newbie? I have been a member of dpr for a couple years or more. I redefined nothing, I gave a completely logical explanation of why it is silly gibberish to say that bokeh IS THE QUALITY of the blur. Quality is not a THING in the real world. It is either a decription of real aspects, or it can be used in a completely subjective way that can't be defined for everyone to agree with.

I assume you're a musician?

Yes, that's what I do for a living, a meager living I assure you, lol.

Does music always deal with things that can be defined or measured? Vibrator, timbre, voice, passion?

The subjective personal part cannot be, the music as math can be.  Again, not seeing where any of this is pertinent

Don't they have quality

Which quality do you mean, the painting is a quality work subjective one, or the 90 degree angle quality that the table has that can be measured and described to all?

, and aren't some variations better than others,

Better is subjective, better to who, you or me?

and wouldn't a musician instantly know the type of sound he likes, even though he couldn't figure out how to measure it.

I would be subjectively liking it, not describing a quality of it.  I would not be able to define the subjective part for others, but i could say that it has the quality of having a piano in the music, it has the quality of being a short song, it has the quality of getting to the chorus before boredom sets it.

Why does one $100,000 violin sound "better" than another?

It may to some and not to others, that would be subjective.

It can't be measured, but it exists

No it doesn't.  The subjective part is all in the mind.  It exists only in the mind.

, even though sound quality is totally objective, the fact is real. Some instruments have a better sound quality.

Nope, some might say the 50 dollar guitar sounds better than the expensive one.  Most wouldn't but even if a few do, it is subjective.

A photographer should have some qualities of the artist in his soul. I feel sorry for you if the only concepts that exist in your mind are those that can be measured, weighed, and counted.

Ridiculous, we are talking about whether a definition is rational or not. A concept does not have to be measured to be a concept. The point stands, the defintion going around is not a definition at all. it's meaningless drivel.

When you get enough experience, you'll know what the quality of the blur is.

Oh come on, going to that tactic now?  I will someday learn and no as much  as you do, so then i will see why my arguents are wrong butyet you can't show me now?  That's laughable.  My arguments are not based on time spent in the field.  they are based on logic, which will always be logic.

Just like musicians, painters, or filmmakers probably have many terms that are vague to me, but clear in their mind.

If they are being illogical, then their illogic will always be illogical, no matter how experienced they become.

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