The whole question of lens sharpness...

Started Jun 12, 2013 | Discussions
Detail Man
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Re: Sharpness in Reasoning ...
In reply to Basalite, Jun 15, 2013

Basalite wrote:

Detail Man wrote:

Basalite wrote:

Detail Man wrote:

Basalite wrote:

Detail Man wrote:

Basalite wrote:

Draek wrote:

Basalite wrote:

What's a "2.4MP monitor?"

A monitor whose resolution is around 2.4 million pixels.

And what "monitor" on the market has such a resolution? I know of none.

As posted by another, just multiply 1200 pixels height by 1920 pixels width = 2.304 Mpixels.

That's not 2.4MP. There is no monitor on the market with 2.4MP.

There's also nothing wrong with viewing images at 100% as that's the only way to tell how sharp your images are.

Nope; another, much more reliable method is to simply make a decently-sized print from it.

Nonsense. If you have a decent quality display you can much more easily determine the level of sharpness than in a print. The printing stage degrades image quality to a certain degree.. As it relates to sharpness, viewing a digital picture on your computer is like looking at a negative or slide with a loupe.

The typical monitor only has around 100 pixels/inch resolution. Some are higher. Printers often can exceed those resolutions. Inks and paper are critical elements in realizing that. Where monitors excel over printers is in contrast-ratio - which is much higher in the case of the typical monitor.

The ability of good monitors of today to show you the true sharpness of your images is not dependent on it being able to display the pixel density needed to produce high quality photographs. Two separate things.

Your words make very little sense.

Which part did you not understand?

The brief declarations that you have not made an effort to explain. You could start by defining what you actually mean by "sharpness". The ability of a medium to depict spatial frequency information depends upon the maximum contrast-ratio as well as the spatial frequency response characteristics. Perhaps that is what you had in mind - but nobody will ever know if you don't explain what you are talking about, so readers can determine your actual understanding of the subject. Please elaborate ...

You are talking "spatial frequency response characteristics" and you can't understand the very simple things I posted?

In fact, in reading this and your other responses to posters on this thread, I don't think that you understand the very simple things that you are posting - and that itself seems to evade you.

You seem to enjoy "sparring" over silly things like where or not any display monitor does or does not have exactly 2,400,000 pixels, and attempting to dismiss outright the thoughts of others - but you are yourself noticeably evasive about the important and central point which renders your bold claims of "objective knowledge" patently hollow - that "sharpness" (like "brightness" and "image quality") are indeed nothing more than subjective terms and phrases which are descriptive only of the implicitly subjective human visual perceptual experience.

Here you betray the subjective, ethereal nature of what you are trying to present as objectivity:

Increasing contrast also doesn't improve sharpness or detail, even if *apparent* sharpness tends to go up.

http://www.dpreview.com/forums/post/51645102

You could still (as I have requested) attempt to provide an objective defintion of what you mean by "sharpness". Otherwise, what you are doing is simply imagining that all the world must surely perceive reality precisely as your eyeballs happen to, or they are otherwise most certainly in error.

What is so difficult to understand? Viewing a high resolution image at 100% on my 27 iMac, or any other good monitor, is like viewing an enlarged negative or slide under a loupe or on a piece of enlargement paper in the darkroom. It's the best way to determine whether an image is sharp. A monitor also does not need to have 300PPi resolution to make that so.

You seem to be forgetting that all images (on any display media) differ in their appearance and characteristics depending upon viewing-size and viewing-distance - decimating your assertion. In fact, your proposed magnification of view (involving re-sampling effects and artifacts at all magnifications other than "100%") at best is depecting something that you claim does not even exist:

"Nearby details?" No such a term. It doesn't even make sense in the context of the discussion.

http://www.dpreview.com/forums/post/51645848

A print, and especially so with the digital processes of today, can easily make a less than take sharp image look "sharp." It is a poor, inefficient and backwards way of determining the true sharpness of a digital image.

I am no particular fan of printed images - but you persist in using an objectively undefinable term.

To assist you in your perhaps unlikely future meditations upon the nature and (the possibility of any) objective meaning of the term "sharpness" that you persist in slinging around as "objective truth", have a look at this statement by Bob Atkins relating to the findings of E.M.Grainger and K.N.Cupery:

... the subjective sharpness of a print corresponds to the area under the MTF curve between the spatial frequencies of (0.5 x magnification) and (2 x magnification) when spatial frequency is plotted on a logarithmic scale.

http://www.bobatkins.com/photography/technical/mtf/sqf1.html

Note that this finding rips a wide and gaping hole in your assumptions that "sharpness" (as subjectively perceived by human visual systems) is independent of the spatial frequency response of the human visual system as affected by viewing-size and viewing-distance, as well as the composite system spatial frequency response and the signal/noise ratio as a function of spatial frequency of the recorded, processed, and displayed image-data. Perhaps food for thought ...

I like to "pixel peep" - but I don't foolishly imagine that doing so allows me to see some overarching and invariant objective perceptual truth. Let me know if you would like to see further indications that your wielding of the ethereal term "sharpness" constitutes little more than a fool's errand.

DM ...

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Re: Sharpness in Reasoning ...
In reply to Detail Man, Jun 17, 2013

Detail Man wrote.

You seem to enjoy "sparring" over silly things like where or not any display monitor does or does not have exactly 2,400,000 pixels, and attempting to dismiss outright the thoughts of others - but you are yourself noticeably evasive about the important and central point which renders your bold claims of "objective knowledge" patently hollow - that "sharpness" (like "brightness" and "image quality") are indeed nothing more than subjective terms and phrases which are descriptive only of the implicitly subjective human visual perceptual experience.

Here you betray the subjective, ethereal nature of what you are trying to present as objectivity:

Increasing contrast also doesn't improve sharpness or detail, even if *apparent* sharpness tends to go up.

http://www.dpreview.com/forums/post/51645102

You could still (as I have requested) attempt to provide an objective defintion of what you mean by "sharpness". Otherwise, what you are doing is simply imagining that all the world must surely perceive reality precisely as your eyeballs happen to, or they are otherwise most certainly in error.

What is so difficult to understand? Viewing a high resolution image at 100% on my 27 iMac, or any other good monitor, is like viewing an enlarged negative or slide under a loupe or on a piece of enlargement paper in the darkroom. It's the best way to determine whether an image is sharp. A monitor also does not need to have 300PPi resolution to make that so.

You seem to be forgetting that all images (on any display media) differ in their appearance and characteristics depending upon viewing-size and viewing-distance - decimating your assertion. In fact, your proposed magnification of view (involving re-sampling effects and artifacts at all magnifications other than "100%") at best is depecting something that you claim does not even exist:

"Nearby details?" No such a term. It doesn't even make sense in the context of the discussion.

http://www.dpreview.com/forums/post/51645848

A print, and especially so with the digital processes of today, can easily make a less than take sharp image look "sharp." It is a poor, inefficient and backwards way of determining the true sharpness of a digital image.

I am no particular fan of printed images - but you persist in using an objectively undefinable term.

To assist you in your perhaps unlikely future meditations upon the nature and (the possibility of any) objective meaning of the term "sharpness" that you persist in slinging around as "objective truth", have a look at this statement by Bob Atkins relating to the findings of E.M.Grainger and K.N.Cupery:

... the subjective sharpness of a print corresponds to the area under the MTF curve between the spatial frequencies of (0.5 x magnification) and (2 x magnification) when spatial frequency is plotted on a logarithmic scale.

http://www.bobatkins.com/photography/technical/mtf/sqf1.html

Note that this finding rips a wide and gaping hole in your assumptions that "sharpness" (as subjectively perceived by human visual systems) is independent of the spatial frequency response of the human visual system as affected by viewing-size and viewing-distance, as well as the composite system spatial frequency response and the signal/noise ratio as a function of spatial frequency of the recorded, processed, and displayed image-data. Perhaps food for thought ...

I like to "pixel peep" - but I don't foolishly imagine that doing so allows me to see some overarching and invariant objective perceptual truth. Let me know if you would like to see further indications that your wielding of the ethereal term "sharpness" constitutes little more than a fool's errand.

DM ...

Bloody hell, is this all the nonsense you think one needs to determine what is and isn't sharp? How on earth did I get through all those years in the darkroom without all that?

I hope for your own good you don't view the rest of your life with such unneeded and ridiculous complexity.

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Re: Sharpness not too important on 2.4MP monitor ...
In reply to Draek, Jun 17, 2013

Draek wrote:

Basalite wrote:

2048x1152 is a very uncommon resolution

All resolutions other than 1024x768, 1366x768 and 1920x1080 can be said to be "uncommon". However, a resolution sported by more than one monitor by more than one maker should have no problems being counted alongside 1600x1200, 1280x1024 and the rest at the very least.

Still very uncommon.

and still not a 2.4MP monitor.

Yes, it is; do read the Wikipedia article on "significant digits".

No, simple math says otherwise.

As I said, there is no such a thing as a 2.4MP monitor.

See above.

The math says otherwise,

Photography, and the related hardware, is a technical field besides an artistic one. People need to be corrected when using terms that are obviously incorrect.

Exactly. So go read that article, because the notion of signfiicant digits is damn important in Physics and the other physical sciences, where rounding 2.36 down to 2.3 as you're doing now is considered a very grave mistake.

??? Where I'd I round anything? The only people that are taking license to round things off are those claiming there is such a thing as a 2.4 MP monitor.

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Detail Man
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Re: Sharpness in Reasoning ...
In reply to Basalite, Jun 17, 2013

Basalite wrote:

Detail Man wrote.

You seem to enjoy "sparring" over silly things like where or not any display monitor does or does not have exactly 2,400,000 pixels, and attempting to dismiss outright the thoughts of others - but you are yourself noticeably evasive about the important and central point which renders your bold claims of "objective knowledge" patently hollow - that "sharpness" (like "brightness" and "image quality") are indeed nothing more than subjective terms and phrases which are descriptive only of the implicitly subjective human visual perceptual experience.

Here you betray the subjective, ethereal nature of what you are trying to present as objectivity:

Increasing contrast also doesn't improve sharpness or detail, even if *apparent* sharpness tends to go up.

http://www.dpreview.com/forums/post/51645102

You could still (as I have requested) attempt to provide an objective defintion of what you mean by "sharpness". Otherwise, what you are doing is simply imagining that all the world must surely perceive reality precisely as your eyeballs happen to, or they are otherwise most certainly in error.

What is so difficult to understand? Viewing a high resolution image at 100% on my 27 iMac, or any other good monitor, is like viewing an enlarged negative or slide under a loupe or on a piece of enlargement paper in the darkroom. It's the best way to determine whether an image is sharp. A monitor also does not need to have 300PPi resolution to make that so.

You seem to be forgetting that all images (on any display media) differ in their appearance and characteristics depending upon viewing-size and viewing-distance - decimating your assertion. In fact, your proposed magnification of view (involving re-sampling effects and artifacts at all magnifications other than "100%") at best is depecting something that you claim does not even exist:

"Nearby details?" No such a term. It doesn't even make sense in the context of the discussion.

http://www.dpreview.com/forums/post/51645848

A print, and especially so with the digital processes of today, can easily make a less than take sharp image look "sharp." It is a poor, inefficient and backwards way of determining the true sharpness of a digital image.

I am no particular fan of printed images - but you persist in using an objectively undefinable term.

To assist you in your perhaps unlikely future meditations upon the nature and (the possibility of any) objective meaning of the term "sharpness" that you persist in slinging around as "objective truth", have a look at this statement by Bob Atkins relating to the findings of E.M.Grainger and K.N.Cupery:

... the subjective sharpness of a print corresponds to the area under the MTF curve between the spatial frequencies of (0.5 x magnification) and (2 x magnification) when spatial frequency is plotted on a logarithmic scale.

http://www.bobatkins.com/photography/technical/mtf/sqf1.html

Note that this finding rips a wide and gaping hole in your assumptions that "sharpness" (as subjectively perceived by human visual systems) is independent of the spatial frequency response of the human visual system as affected by viewing-size and viewing-distance, as well as the composite system spatial frequency response and the signal/noise ratio as a function of spatial frequency of the recorded, processed, and displayed image-data. Perhaps food for thought ...

I like to "pixel peep" - but I don't foolishly imagine that doing so allows me to see some overarching and invariant objective perceptual truth. Let me know if you would like to see further indications that your wielding of the ethereal term "sharpness" constitutes little more than a fool's errand.

Bloody hell, is this all the nonsense you think one needs to determine what is and isn't sharp? How on earth did I get through all those years in the darkroom without all that?

Rather dimly, it appears. Seems like all your dodging has led to your burning yourself.

I hope for your own good you don't view the rest of your life with such unneeded and ridiculous complexity.

If I need a life coach, I'll try to remember to put you on the list, at the bottom.

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olliess
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Re: Sharpness not too important on 2.4MP monitor ...
In reply to Basalite, Jun 17, 2013

Basalite wrote:

Where I'd I round anything? The only people that are taking license to round things off are those claiming there is such a thing as a 2.4 MP monitor.

Out of curiosity, what do you tell people is the resolution of your Sigma cameras?

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fad
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Re: Good one.
In reply to Rick Knepper, Jun 17, 2013

Rick Knepper wrote:

I want every aspect of the lenses I purchase to be as defect free as possible. As another poster mentioned, pricing controls a person's attitude towards such attributes. If all lenses were free, we wouldn't be having this debate.

The financially-challenged should just "own" their plight and quit clogging these forums with false arguments. For example, as a landscape shooter, medium format digital is what I really should be shooting for capturing detail but the pricing is beyond what I can spend (a Lotto win notwithstanding). I'm not going to sit here, put on airs and justify my chosen format on the basis of technical excellence when cost is the primary deterrent to moving on and upward.

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Rick Knepper, photographer, non-professional, shooting for pleasure, check my profile for gear list and philosophy. TJ said, "Every generation needs a new revolution".

Fair enough, but only for landscape.

For street, I leave my most expensive lenses home 95+% of the time for lenses that are smaller or have a wider zoom range or focus faster.  Medium format would be useless for me.

And for landscape, at the highest level, the cost of medium format would be nothing compared to the cost of travel and the time needed to work out and wait for the best shot possible.  And I suspect a tripod would do more good than the quality of the lens and sensor.  No?

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Re: Good one.
In reply to fad, Jun 17, 2013

fad wrote:

Rick Knepper wrote:

I want every aspect of the lenses I purchase to be as defect free as possible. As another poster mentioned, pricing controls a person's attitude towards such attributes. If all lenses were free, we wouldn't be having this debate.

The financially-challenged should just "own" their plight and quit clogging these forums with false arguments. For example, as a landscape shooter, medium format digital is what I really should be shooting for capturing detail but the pricing is beyond what I can spend (a Lotto win notwithstanding). I'm not going to sit here, put on airs and justify my chosen format on the basis of technical excellence when cost is the primary deterrent to moving on and upward.

-- hide signature --

Rick Knepper, photographer, non-professional, shooting for pleasure, check my profile for gear list and philosophy. TJ said, "Every generation needs a new revolution".

Fair enough, but only for landscape.

For street, I leave my most expensive lenses home 95+% of the time for lenses that are smaller or have a wider zoom range or focus faster. Medium format would be useless for me.

And for landscape, at the highest level, the cost of medium format would be nothing compared to the cost of travel and the time needed to work out and wait for the best shot possible. And I suspect a tripod would do more good than the quality of the lens and sensor. No?

A superior lens on a tripod will yield a superior picture than a mediocre lens on a tripod.

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Draek
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Re: Sharpness not too important on 2.4MP monitor ...
In reply to Basalite, Jun 17, 2013

Basalite wrote:

Still very uncommon.

Not significantly so.

No, simple math says otherwise.

Then learn advanced math; say, at the level of a first-year university course.

The math says otherwise,

No, it doesn't. Sincerely, someone who actually studied the field in university.

??? Where I'd I round anything? The only people that are taking license to round things off are those claiming there is such a thing as a 2.4 MP monitor.

There is. 2048x1152 px = 2359296 px = 2.36 Mpx = 2.4 Mpx.

It would've been different if he had said 2.40 Mpx (a very different number from 2.4 in the physical sciences), but he didn't and thus you're wrong. Did you read the damn article?

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Mark Scott Abeln
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Sharpness versus contrast
In reply to gdourado, Jun 17, 2013

How I think about lens sharpness versus contrast:

The top row is sharp, the bottom row is soft, while the lefthand column shows high contrast, and the right column shows low contrast.

I have an antique Nikon lens which is quite sharp, but it is rather low contrast since its glass is not coated. The histogram of images produced by this lens almost never goes full scale, and I correct for this in post-processing. The detail captured by the lens is otherwise excellent, and other lens defects are minimal.

On the other hand, I have a newer multicoated lens which has plenty of contrast — many of my images are simultaneously over-and-underexposed in places — but it is not particularly sharp, largely due, I think, to the considerable fringing of chromatic aberration. I can remove the fringes, but the softness still remains.

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John1940
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Re: Sharpness in Reasoning ...
In reply to Basalite, Jun 17, 2013

Basalite wrote:

Detail Man wrote.

You seem to enjoy "sparring" over silly things like where or not any display monitor does or does not have exactly 2,400,000 pixels, and attempting to dismiss outright the thoughts of others - but you are yourself noticeably evasive about the important and central point which renders your bold claims of "objective knowledge" patently hollow - that "sharpness" (like "brightness" and "image quality") are indeed nothing more than subjective terms and phrases which are descriptive only of the implicitly subjective human visual perceptual experience.

Here you betray the subjective, ethereal nature of what you are trying to present as objectivity:

Increasing contrast also doesn't improve sharpness or detail, even if *apparent* sharpness tends to go up.

http://www.dpreview.com/forums/post/51645102

You could still (as I have requested) attempt to provide an objective defintion of what you mean by "sharpness". Otherwise, what you are doing is simply imagining that all the world must surely perceive reality precisely as your eyeballs happen to, or they are otherwise most certainly in error.

What is so difficult to understand? Viewing a high resolution image at 100% on my 27 iMac, or any other good monitor, is like viewing an enlarged negative or slide under a loupe or on a piece of enlargement paper in the darkroom. It's the best way to determine whether an image is sharp. A monitor also does not need to have 300PPi resolution to make that so.

You seem to be forgetting that all images (on any display media) differ in their appearance and characteristics depending upon viewing-size and viewing-distance - decimating your assertion. In fact, your proposed magnification of view (involving re-sampling effects and artifacts at all magnifications other than "100%") at best is depecting something that you claim does not even exist:

"Nearby details?" No such a term. It doesn't even make sense in the context of the discussion.

http://www.dpreview.com/forums/post/51645848

A print, and especially so with the digital processes of today, can easily make a less than take sharp image look "sharp." It is a poor, inefficient and backwards way of determining the true sharpness of a digital image.

I am no particular fan of printed images - but you persist in using an objectively undefinable term.

To assist you in your perhaps unlikely future meditations upon the nature and (the possibility of any) objective meaning of the term "sharpness" that you persist in slinging around as "objective truth", have a look at this statement by Bob Atkins relating to the findings of E.M.Grainger and K.N.Cupery:

... the subjective sharpness of a print corresponds to the area under the MTF curve between the spatial frequencies of (0.5 x magnification) and (2 x magnification) when spatial frequency is plotted on a logarithmic scale.

http://www.bobatkins.com/photography/technical/mtf/sqf1.html

Note that this finding rips a wide and gaping hole in your assumptions that "sharpness" (as subjectively perceived by human visual systems) is independent of the spatial frequency response of the human visual system as affected by viewing-size and viewing-distance, as well as the composite system spatial frequency response and the signal/noise ratio as a function of spatial frequency of the recorded, processed, and displayed image-data. Perhaps food for thought ...

I like to "pixel peep" - but I don't foolishly imagine that doing so allows me to see some overarching and invariant objective perceptual truth. Let me know if you would like to see further indications that your wielding of the ethereal term "sharpness" constitutes little more than a fool's errand.

DM ...

Bloody hell, is this all the nonsense you think one needs to determine what is and isn't sharp? How on earth did I get through all those years in the darkroom without all that?

I hope for your own good you don't view the rest of your life with such unneeded and ridiculous complexity.

Basalite, I'm wondering whether you are just being argumentative with Detail Man or simply do not understand how monitors work and, secondly, how easy it is to test lens sharpness (to some reasonable level) with something like a Nikon 800E if the lens has the Nikon mount.

If two lenses are much sharper than "36 MP" (equivalent) but one is three times sharper than the other, you cannot tel the difference with the 36 MP 800E. And, you can use any decent calibrated HDTV monitor to verify that. But, you have to zoom in to "actual pixels" in order to do side-by-side image comparisons. You will have to scroll both images to the same part of the full 36 MP since the monitor can only display about 2 MP at a time (divided by two since you will be showing two lens results at a time).

If, on the other hand, one lens has less sharpness in the image corners that is detectable by a 36 MP sensor, for example, then when you look at a 2 MP window of each 36 MP image by scrolling to that area for both images, you will see the difference.

This is an easy test to do. The sharpest lens I use regularly is a Canon EF-s 60mm f/2.8 macro. If I test any other lens such as a travel zoom that I can set to 60mm, it's easy to see the IQ I am giving up at that focal length for the zoom lens's convenience. That's why I usually take the macro with me during traveling also.

John1940

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BertIverson
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I borrowed Mark Scott Abeln's diagram (see his post today -- below)
In reply to BertIverson, Jun 17, 2013

BertIverson wrote:

gdourado wrote:

... Do we really need more and more sharpness? For portraits, events, models... is super sharpness even a good thing? How much is enough? ...

My take on this is simple. If one can fill the frame (avoiding cropping), lens sharpness is usually irrelevant when viewing on a 2.4MP monitor. Viewing a 16MP shot on a 2.4MP monitor means about 4-6 sensor pixels are rendered into 1 pixel on the monitor. In the case of a zoom lens, it only needs to be real sharp at the extreme long end. At lesser FL one will fill the frame (see above)...

Mark does a great job of explaining sharpness/contrast in lenses. See his post below.

I have borrowed half of Mark's diagram to demonstrate my OP statement about viewing high resolution photos on 2.1/2.3/2.4 MP monitors. To illustrate, let's assume a 20MP shot viewed on a 2.2MP monitor (9 photo pixels are rendered as 1 monitor pixel)

9 photo pixels averaged when a 20 MP shot is rendered on a 2.2 MP monitor

One can see that the blurriness is now seen at the monitor pixel level instead of the photo pixel level. The lens blurriness is therefore reduced 3:1 compared to viewing on a 20MP monitor or large 300 PPI print.

NOTE: My original post was regarding the need for "sharp" lenses when one views photos  on these 2.x MP monitors. (not when pixel peeping or printing large at 300 PPI)

Sorry to revive this rather raucous thread but Mark's test photo intrigued me to see this alleged effect for myself.

Cheers,
Bert

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John1940
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Re: The whole question of lens sharpness...
In reply to OpticsEngineer, Jun 17, 2013

OpticsEngineer wrote:

Here is a nice reference from Zeiss on sharpness and other things concerming lens quality. It is written from the perspective of photographers.

As others have said, sharpness is important and easily understood, but one of only many important qualities that may be harder to understand.

For some type of images sharpness might be the dominating thing, for instance a models hair being blown by a large fan (not in the picture) and lit by a flash.

http://www.zeiss.com/c12567a8003b8b6f/embedtitelintern/cln_30_mtf_en/$file/cln_mtf_kurven_en.pdf

Thanks for the reference.

John1940

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edispics
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Re: The whole question of lens sharpness...
In reply to John1940, Jun 17, 2013

Ditto

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garrywatson
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Re: The whole question of lens sharpness...
In reply to gdourado, Jun 19, 2013

Photography is all about sharpness and if a photograph is not sharp, it won’t be eye-catchy. In fact, anyone can click a picture but to capture an eye-catching shot, you have to ensure its absolute sharp. Yes, we photographers are obsessed with sharpness but that’s what speaks about our skills. Lesser the sharpness, more amateur you would sound. See, in photography, you need to freeze a moment and if your image is not sharp, the details will be lost. Whether it’s about using a lens or camera stabilizing equipments such as tripod, shutter release, camera remote, etc.; increasing the sharpness has always been the obsession of every photographer be it a professional like me or an amateur like my brother. So, I don’t find anything wrong about being obsessed with sharpness. It’s all about achieving perfection.

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Detail Man
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Re: Good one ...
In reply to Basalite, Jun 19, 2013

Basalite wrote:

A superior lens on a tripod will yield a superior picture than a mediocre lens on a tripod.

Heavens above, where would we be without such incisive and profound insights flowing forth.

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Mark Smith
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Re: Is Apple 30" 2.4mp?
In reply to Basalite, Jun 19, 2013

Basalite wrote:

Mark Smith wrote:

Basalite wrote:

That's not 2.4MP. There is no monitor on the market with 2.4MP.

For a while I used an Apple monitor that was 30" 2560 x 1600 they make a 27" with 2560x1440

If they aren't 2.4 mp then I'm not sure what is.

You are not sure is right. Do the math. Those are not 2.4MP monitors.

I did the maths and what's more the Apple pdf for the display puts this in the tech specs

"the Apple 30" LCD is the largest display ever created for use on a personal computer its 2560x1600 resolution panel has over 4 million pixels"

So help me with the maths because every source I can find tells me that panel had 4+ million pixels

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Alphoid
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Re: The whole question of lens sharpness...
In reply to Basalite, Jun 19, 2013

Basalite wrote:

No, it's impossible to increase real sharpness if it wasn't there to begin with. There is also no point in a soft focus lens when you can use software to blur a sharp lens.

This is, mathematically, not true:

  1. It's possible to increase real sharpness. This requires having a model of the way in which the lens is not sharp (not just a 'sharpness' slider). If you do the sharpening badly, you will end up with ugly relics. If you do it right, the only downside will be that noise will increase as well.
  2. Soft focus, on the other hand, is impossible to replicate in post-processing. Software treats the image as 2d. The light coming into a camera is a light field. As a result, lens soft focus effects can be different than anything postprocessing can do (whether better or worse is subjective).

Practically, of course, I agree.

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Jack Hogan
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The whole question of contrast...
In reply to garrywatson, Jun 19, 2013

garrywatson wrote:

Photography is all about sharpness..

I tend to agree with a minor substitution: Photography (or perhaps we should say vision) is all about contrast, different types of contrast: an image without contrast contains virtually no information.  Conversely all of the information perceived from an image is contained in different types of contrast.

We have amplitude contrast (the range of dark and bright /luminance pixels), we have spatial contrast (local, global) , we have color contrast, we have pattern and shape contrast , etc.  These contrasts or lack thereof are what imo makes an image interesting .  Sharpness is but one of them, of the micro-spatial sort.

Jack

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Deleted1929
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Re: The whole question of lens sharpness...
In reply to Alphoid, Jun 20, 2013

> It's possible to increase real sharpness. This requires having a model of the way in which the lens is not sharp (not just a 'sharpness' slider)

This isn't true.  You can never fully reverse the many optical effects.  You'd be breaking a number of well established physical laws if you could.

Even if you attempted this to the limits of physics you'd probably be frustrated by sample variations in the lenses.

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StephenG

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Detail Man
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Re: The whole question of lens sharpness ...
In reply to Deleted1929, Jun 20, 2013

sjgcit wrote:

> It's possible to increase real sharpness. This requires having a model of the way in which the lens is not sharp (not just a 'sharpness' slider)

This isn't true. You can never fully reverse the many optical effects. You'd be breaking a number of well established physical laws if you could.

Given that the term "sharpness" (like "brightness" and "image quality") is solely a descriptor of human perceptual impressions - and not an objectively defined property, anyway - it seems that it would be hard to "break well established physical laws" when human perception itself has not been reduced to neat little atomized mathematical factoids.

However, the composite system MTF response (which is objectively characterizable) can indeed be improved. DxO Optics Pro's so-called "Lens Softness" optical corrections do so every day:

http://www.dxo.com/intl/photography/tutorials/enhance-sharpness-your-camera-dxo-optics-pro

Even if you attempted this to the limits of physics you'd probably be frustrated by sample variations in the lenses.

It seems to work rather well with my copies. Sorry if you may find that a bit disappointing ...

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