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How much sharpness do you need?

Toothwalker
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p.11 #1 · How much sharpness do you need?

Bifurcator wrote:
You question the authority of the BPD? What are you a Learian devotee from the 60's

Send me a copy then.

It is just that there can be no meaningful discussion if everybody uses their own definitions of terms. I just checked a dozen of optics books, and did not find the term microcontrast in any of them. On the other hand, resolution, contrast, and sharpness are defined. There seems to be consensus that sharpness is a subjective concept, whereas resolution and contrast are not.

This is meant as a reaction to several messages in this thread, not the BPD in particular.

Aug 30, 2012 at 09:45 PM

Bifurcator
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p.11 #2 · How much sharpness do you need?

Yeah.

Just a note to add that when we view images it's all subjective concept - probably 100% of it. Hundreds of thousands of experiments have been carried out whereby reprogramming the brain through conditioning, hypnosis, post hypnotic suggestion, and even by manipulating electrical fields we can make a person see and even interact with visual reality that doesn't exist - or highly modified realities. Like programming a person's mind to see a rope when everyone else is seeing a snake. Even when it bites the manipulated viewer they see and feel only a thorn or splinter as their mind manufactures the reality to account for the phenomena. A common one is mistaken personages. Program a person to see only and old ladies in place of young boys and their minds will manufacture all of the details (wrinkled skin, bent appearance, crackled voice) they normally see hear and smell in association with old ladies - every time they encounter a young man. A good and perfectly realistic example of this can be seen in a pretty good hollywood dramafication called "Shallow Hal" with that Tenacious D dude.

Of course we probably consider resolution and contrast as quantifiable due to machine vision and testing equipment... But I just wanted to point out how indeed fleeting and subjective most of reality actually is.

Oh, and the BPD is so high level and elite no one has ever actually seen a copy! Therefore it remains irreproachable - as indeed it has throughout the ages of it's existence!

Aug 30, 2012 at 10:05 PM

philip_pj
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p.11 #3 · How much sharpness do you need?

Toothwalker,

You may have searched for the one word (oneword) permutation, rather than 'micro contrast'. As an aside, I favour 'micro-contrast' - to indicate the two concepts are closely coupled.

In any case, I point you to this document featuring the term, I hope the author is sufficiently well-credentialed for you:

http://www.zeiss.de/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf

And it gives me another chance to point to something more akin to Bif's above statement regarding the importance of 'something more' at the edge of vision.

This is from the same document, in the context of MTF:

"But what does ‘contrast rendition’ actually mean? We must not forget that when we
talk about ‘contrast’ we always mean micro contrast, i.e. structures, which we
can just about see or just cannot see with the naked eye, for example on a slide."

Zeiss are also big on the *subjective appearance* of sharpness, cited in the same paper, and elsewhere in their series. So maybe we can further modify the thread subject title to 'How much apparent sharpness do you need, punk?'

Sorry, added the last word in as a reference to Dirty Harry's likely appearance at Mitt's big do in the US today, please forgive me. Or not, as the case may be.

Aug 31, 2012 at 02:30 AM

Toothwalker
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p.11 #4 · How much sharpness do you need?

philip_pj wrote:
You may have searched for the one word (oneword) permutation, rather than 'micro contrast'. As an aside, I favour 'micro-contrast' - to indicate the two concepts are closely coupled.

Microsoft, microscope, microclimate, .. it is tempting to write microcontrast as one word. I would have found "micro contrast" or "micro-contrast", though.

In any case, I point you to this document featuring the term, I hope the author is sufficiently well-credentialed for you:

http://www.zeiss.de/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf

And it gives me another chance to point to something more akin to Bif's above statement regarding the importance of 'something more' at the edge of vision.

This is from the same document, in the context of MTF:

"But what does ‘contrast rendition’ actually mean? We must not forget that when we
talk about ‘contrast’ we always mean micro contrast, i.e. structures, which we
can just about see or just cannot see with the naked eye, for example on a slide."

He is either not telling the truth (this very thread is sufficient evidence) or he is using the majestic plural.

I don't think the existence of his document is sufficient to get the term adopted by an appropriate standards body, but at least it is a start. Thanks. Used this way, it is a fairly subjective term though.

Zeiss are also big on the *subjective appearance* of sharpness, cited in the same paper, and elsewhere in their series. So maybe we can further modify the thread subject title to 'How much apparent sharpness do you need, punk?'

Sorry, added the last word in as a reference to Dirty Harry's likely appearance at Mitt's big do in the US today, please forgive me. Or not, as the case may be.

At least he was on the right track in the movies.

Sep 01, 2012 at 06:36 PM

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