The whole question of lens sharpness...

Started Jun 12, 2013 | Discussions
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Re: Sharpness not too important on 2.4MP monitor ...
In reply to Detail Man, Jun 15, 2013

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?

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.

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.

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Re: The whole question of lens sharpness...
In reply to looper1234, Jun 15, 2013

looper1234 wrote:

Basalite wrote:

There is nothing "vague" about the definition of sharpness.

it's vague because it is not quantified in a universally accepted way, DxOmark did the best job they could by introducing standardized test methods and the principle, "perceptual mpx"

but these type of quantification are a far cry from what one would consider workable in the world of science.

one should consider an entity defined if it can be presented in vector or scalar form with SI units. pMp is a good unit for sharpness only if the tests used to generate these quantities are perfect and its results free from all outside influence.

the concept of sharpness cannot free itself from these constraints because it is too complex a principle, and the only way to quantify it is to do what Dxomark did, to standardized and simplify it to a form of resolution.

Determining sharpness is as simple as looking at something, assuming you have good vision to begin with. You are grossly over-thinking the subject, as a lot of modern day "photographers" like to do in our digital age.

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Re: Is Apple 30" 2.4mp?
In reply to Mark Smith, Jun 15, 2013

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.

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Re: Contrast and color are MORE important :-)
In reply to salla30, Jun 15, 2013

salla30 wrote:

I agree wholeheartedly with this.

Colour and contrast, the way the light plays naturally within an image is so important.

And colour, so important, take the RX1 for example, do a search on Flickr for RX1. A whole load of thumbs come up and the first thing you notice is the vivid, vibrant colours.

Sharpness is a nice attribute, but it's really very secondary at pixel level. The VAST majority of images are viewed at HD or much less (cellphone level or tablet) and as such the colour and dynamics of the image are FAR more important.

Color saturation and contrast can be adjusted, true sharpness can not.

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edispics
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Re: Contrast and color just as important
In reply to Basalite, Jun 15, 2013

Basalite wrote:

NancyP wrote:

Color and contrast are what make an image "pop". Sharpness tends to be associated with good color and contrast. Not all images need to be ultra-sharp, but all images benefit from good contrast. Ultra-sharp for portraits requires some softening in post-processing.

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NancyP

There is no such a requirement to soften portraits. Some of the most interesting portraits are those that are razor sharp.

Today contrast and color can be taken care of digitally.

There are interesting portraits that are "sharp" and there are interesting portraits that are"soft". There is no "requirement" that they be either. The choice is based on either artistic preferences or customer preference.

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Allan Olesen
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Re: Contrast and color are MORE important :-)
In reply to Basalite, Jun 15, 2013

Basalite wrote:

Color saturation and contrast can be adjusted, true sharpness can not.

I often see this claim.

I can honestly say that I am not competent to increase the detail contrast of my photos to make them look as if they came from a Zeiss lens. And I haven't really seen examples of anyone else being able to do that.

So perhaps contrast is harder to do in PP than you claim.

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edispics
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Re: Contrast and color are MORE important :-)
In reply to Basalite, Jun 15, 2013

Color saturation and contrast can be adjusted, true sharpness can not.

Hmmm, always love the word "true". Wonder if the reverse is "true":

Sharpness can be adjusted but "true" color saturation and contrast can not.

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Re: Contrast and color just as important
In reply to edispics, Jun 15, 2013

edispics wrote:

Basalite wrote:

NancyP wrote:

Color and contrast are what make an image "pop". Sharpness tends to be associated with good color and contrast. Not all images need to be ultra-sharp, but all images benefit from good contrast. Ultra-sharp for portraits requires some softening in post-processing.

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NancyP

There is no such a requirement to soften portraits. Some of the most interesting portraits are those that are razor sharp.

Today contrast and color can be taken care of digitally.

There are interesting portraits that are "sharp" and there are interesting portraits that are"soft". There is no "requirement" that they be either. The choice is based on either artistic preferences or customer preference.

Obviously, but you can't add true sharpness if it wasn't there in the first place, unlike simply blurring your image in Photoshop or any other image editing app.

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Re: Contrast and color are MORE important :-)
In reply to Allan Olesen, Jun 15, 2013

Allan Olesen wrote:

Basalite wrote:

Color saturation and contrast can be adjusted, true sharpness can not.

I often see this claim.

I can honestly say that I am not competent to increase the detail contrast of my photos to make them look as if they came from a Zeiss lens. And I haven't really seen examples of anyone else being able to do that.

So perhaps contrast is harder to do in PP than you claim.

It is not a "claim," it is a simple reality. Color saturation and contrast are easily adjustable in software. Sharpness adjustment in software is not true sharpness.

Increasing contrast also doesn't improve sharpness or detail, even if *apparent* sharpness tends to go up. Your photos, as it relates to sharpness, don't look like they came from a Zeiss lens simply because your lenses are not as sharp. No amount of contrast enhancement or unsharp mask is going to change that.

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Re: Contrast and color are MORE important :-)
In reply to edispics, Jun 15, 2013

edispics wrote:

Color saturation and contrast can be adjusted, true sharpness can not.

Hmmm, always love the word "true". Wonder if the reverse is "true":

Sharpness can be adjusted but "true" color saturation and contrast can not.

Unfortunately today more and more people have a problem with anything being "true" or definable.

I suggest you learn more about the subject.

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JudyN
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Re: The whole question of lens sharpness...
In reply to Chris R-UK, Jun 15, 2013

Chris R-UK wrote:

Basalite wrote:

[snip]

There is no such a thing as an image being "oversharp" because of a lens.

But is can certainly be "oversharp" because of excessive sharpening in post processing. I think that that is what the previous poster was referring to.

It's also possible that the poster had not oversharpened.  Many sites where you upload photos do (additional) sharpening whether you want them to or not.  If you have already sharpened, it can make a mess of the image.

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Allan Olesen
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Re: Contrast and color are MORE important :-)
In reply to Basalite, Jun 15, 2013

Basalite wrote:

Allan Olesen wrote:

Basalite wrote:

Color saturation and contrast can be adjusted, true sharpness can not.

I often see this claim.

I can honestly say that I am not competent to increase the detail contrast of my photos to make them look as if they came from a Zeiss lens. And I haven't really seen examples of anyone else being able to do that.

So perhaps contrast is harder to do in PP than you claim.

It is not a "claim," it is a simple reality. Color saturation and contrast are easily adjustable in software. Sharpness adjustment in software is not true sharpness.

My point was that if you just pull the contrast sliders, you will get more overall contrast, but you can't achieve the detail contrast of a good lens without increasing overall contrast so much that the photo seems unnatural.

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edispics
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Good one ...
In reply to Basalite, Jun 15, 2013

Basalite wrote:

BertIverson wrote:

Basalite wrote:

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

1920x1200 is pretty common and close to 2.4MP

Bert

1920x1200 monitors are no longer "pretty common." They are actually rare now. It is also not a 2.4MP monitor, which is no surprise considering there is no such a thing as a 2.4MP monitor.

I read the original post about 2.4MP and compared that to my monitors and said to myself, "OK, I know what he is referring to." Then I read further and saw that he was saying that displaying a photo with more megapixels on a monitor with less megapixels would result in averaging and thus obscure the potential benefit of an ultra-expensive, ultra-sharp lens. So My takeaway was, ok, let's think about that one.

Your takeaway was gosh darn, there ain't no monitor out there with a resolution of exactly 2.4MP and the universe as we now know it will come to an end if this error is not rectified immediately.

You can have your take on it. I prefer mine.

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Re: Good one ...
In reply to edispics, Jun 15, 2013

edispics wrote:

Basalite wrote:

BertIverson wrote:

Basalite wrote:

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

1920x1200 is pretty common and close to 2.4MP

Bert

1920x1200 monitors are no longer "pretty common." They are actually rare now. It is also not a 2.4MP monitor, which is no surprise considering there is no such a thing as a 2.4MP monitor.

I read the original post about 2.4MP and compared that to my monitors and said to myself, "OK, I know what he is referring to." Then I read further and saw that he was saying that displaying a photo with more megapixels on a monitor with less megapixels would result in averaging and thus obscure the potential benefit of an ultra-expensive, ultra-sharp lens. So My takeaway was, ok, let's think about that one.

Your takeaway was gosh darn, there ain't no monitor out there with a resolution of exactly 2.4MP and the universe as we now know it will come to an end if this error is not rectified immediately.

You can have your take on it. I prefer mine.

I was addressing the **fact** that there is no such thing as a 2.4MP monitor. Try not to muddy the obvious.

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Re: Contrast and color are MORE important :-)
In reply to Allan Olesen, Jun 15, 2013

Allan Olesen wrote:

Basalite wrote:

Allan Olesen wrote:

Basalite wrote:

Color saturation and contrast can be adjusted, true sharpness can not.

I often see this claim.

I can honestly say that I am not competent to increase the detail contrast of my photos to make them look as if they came from a Zeiss lens. And I haven't really seen examples of anyone else being able to do that.

So perhaps contrast is harder to do in PP than you claim.

It is not a "claim," it is a simple reality. Color saturation and contrast are easily adjustable in software. Sharpness adjustment in software is not true sharpness.

My point was that if you just pull the contrast sliders, you will get more overall contrast, but you can't achieve the detail contrast of a good lens without increasing overall contrast so much that the photo seems unnatural.

The "detail contrast" (no such a term) you speak of is due to a sharper lens, besides sensor quality. That said, one can do a mid tone contrast adjustment without affecting highs and lows. A very sharp lens with lower contrast can have its contrast increased in software and you will see what you are looking for.

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Allan Olesen
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Re: Contrast and color are MORE important :-)
In reply to Basalite, Jun 15, 2013

Basalite wrote:

The "detail contrast" (no such a term)

Then let us call it "Contrast between nearby details". Not to confuse with resolution which works on a much smaller scale. A lens can have high resolution but still lack contrast between nearby details.

you speak of is due to a sharper lens, besides sensor quality. That said, one can do a mid tone contrast adjustment without affecting highs and lows. A very sharp lens with lower contrast can have its contrast increased in software and you will see what you are looking for.

If you do a mid tone contrast adjustment, it will affect the overall contrast, not just the contrast between nearby details.

So if people refer to the contrast between nearby details when they talk about the contrast of a lens, you can't easily reproduce that property of the lens in PP.

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Re: Contrast and color are MORE important :-)
In reply to Allan Olesen, Jun 15, 2013

Allan Olesen wrote:

Basalite wrote:

The "detail contrast" (no such a term)

Then let us call it "Contrast between nearby details". Not to confuse with resolution which works on a much smaller scale. A lens can have high resolution but still lack contrast between nearby details.

If a lens, sharp or not, lacks contrast then the entire image is affected.

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

you speak of is due to a sharper lens, besides sensor quality. That said, one can do a mid tone contrast adjustment without affecting highs and lows. A very sharp lens with lower contrast can have its contrast increased in software and you will see what you are looking for.

If you do a mid tone contrast adjustment, it will affect the overall contrast, not just the contrast between nearby details.

No, that's why it is called a mid tone adjustment.

So if people refer to the contrast between nearby details when they talk about the contrast of a lens, you can't easily reproduce that property of the lens in PP.

Once again, low contrast in an image can easily be adjusted for. Adding contrast to a sharp low contrast picture will greatly increase apparent detail throughout the image. I would lose the term "nearby details" as it means nothing.

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BertIverson
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edispics -- Thank you ...
In reply to edispics, Jun 15, 2013

edispics wrote:

Basalite wrote:

BertIverson wrote:

Basalite wrote:

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

1920x1200 is pretty common and close to 2.4MP

Bert

1920x1200 monitors are no longer "pretty common." They are actually rare now. It is also not a 2.4MP monitor, which is no surprise considering there is no such a thing as a 2.4MP monitor.

I read the original post about 2.4MP and compared that to my monitors and said to myself, "OK, I know what he is referring to." Then I read further and saw that he was saying that displaying a photo with more megapixels on a monitor with less megapixels would result in averaging and thus obscure the potential benefit of an ultra-expensive, ultra-sharp lens. So My takeaway was, ok, let's think about that one.

Your takeaway was gosh darn, there ain't no monitor out there with a resolution of exactly 2.4MP and the universe as we now know it will come to an end if this error is not rectified immediately.

You can have your take on it. I prefer mine.

edispics,

Thank you.
You obviously understood what I was trying to say in my original post. Indeed my arithmetic was deficient since 1920x1200 is closer to 2.3MP than 2.4MP but I simply think of my monitor as 2K by 1.2K
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Re: edispics -- Thank you ...
In reply to BertIverson, Jun 15, 2013

BertIverson wrote:

edispics wrote:

Basalite wrote:

BertIverson wrote:

Basalite wrote:

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

1920x1200 is pretty common and close to 2.4MP

Bert

1920x1200 monitors are no longer "pretty common." They are actually rare now. It is also not a 2.4MP monitor, which is no surprise considering there is no such a thing as a 2.4MP monitor.

I read the original post about 2.4MP and compared that to my monitors and said to myself, "OK, I know what he is referring to." Then I read further and saw that he was saying that displaying a photo with more megapixels on a monitor with less megapixels would result in averaging and thus obscure the potential benefit of an ultra-expensive, ultra-sharp lens. So My takeaway was, ok, let's think about that one.

Your takeaway was gosh darn, there ain't no monitor out there with a resolution of exactly 2.4MP and the universe as we now know it will come to an end if this error is not rectified immediately.

You can have your take on it. I prefer mine.

edispics,

Thank you.
You obviously understood what I was trying to say in my original post. Indeed my arithmetic was deficient since 1920x1200 is closer to 2.3MP than 2.4MP but I simply think of my monitor as 2K by 1.2K
Bert

My correcting you on the fact that a 2.4MP monitor does not exist had nothing to do with the rest of your post. That should be obvious.

Your 2K by 1.2K description is also mathematically incorrect and certainly a very unusual way to describe a computer monitor.

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Draek
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Re: Sharpness not too important on 2.4MP monitor ...
In reply to Basalite, Jun 15, 2013

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.

and still not a 2.4MP monitor.

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

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

See above.

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.

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