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arash_hazeghi
08-16-2009, 06:21 PM
Many times in the critique forums, comments are given regarding sharpness and exposure (blown highlights). A problem I see is that perceived sharpness depends on screen resolution as discussed in this thread http://www.birdphotographers.net/forums/showthread.php?t=42700 so I guess sharpness comments should be made with caution, of course there are some cases when blur is evident like motion blur, shake etc.

Also if the screen contrast is set too high or screen is not calibrated correctly bright areas can appear "blown up" only a histogram can verify if there are blown highlights. Is it possible to include a small calibration strip like this (http://i.pbase.com/o6/78/287278/1/75285378.fButmPlS.GreyscaleStep8.JPG) at the bottom of the critique forum pages so the folks can check their screens when looking at each photo ?

Fabs Forns
08-16-2009, 06:28 PM
We have one at the end of the page.

Desmond Chan
08-16-2009, 07:36 PM
A problem I see is that perceived sharpness depends on screen resolution

I doubt it. Sharpness depends on your eyes. I use a small, old fashioned CRT monitor with resolution lowered than most of you guys' LCDs, but I always come to the same conclusion re sharpness as the other members do. If as you said perceived sharpness depends on screen resolution, would you care to explain why I and other members usually are in agreement?


I guess sharpness comments should be made with caution I think it is the other way round. As sharpness is all depends on your eyes, your brain, and your own preferences, if you receive a comment saying that your image is not sharp, and you disagree, and most viewers agree with you, then you can choose to ignore that "unsharpness" comment and go with your own conclusion. I do not think you can tell other members to have the same monitor exactly as yours with settings exactly as yours before they can comment on the sharpness of your photos. Sharpness is in the eye of the beholder. Sid's investigation is futile from the get go IMO. And he also agrees with other that that particular image is not sharp enough, the same conclusion drawn by other members with different monitors of different resolutions.

BTW, I can use the same resolution as yours and if I set the contrast of my monitor low, yours image will still look not as sharp as that one seen on your monitor.


only a histogram can verify if there are blown highlights. I believe Arite has addressed that sometime ago. Histogram is not enough, IMO. One should check the RGB values of those areas. 255 is definitely white with no details. Anything above 247 give you pretty much the same results and same impression of blown highlights. But in the histogram, 247 is not clipped.

BTW, I think I read something written by Fabs somewhere sometime ago that critique forum is more like a poll. I think that's a good way to see it.

arash_hazeghi
08-16-2009, 08:26 PM
I doubt it. Sharpness depends on your eyes. I use a small, old fashioned CRT monitor with resolution lowered than most of you guys' LCDs, but I always come to the same conclusion re sharpness as the other members do. If as you said perceived sharpness depends on screen resolution, would you care to explain why I and other members usually are in agreement?

Well I disagree, please read the other thread for more information, sharpness does depend on the screen. Some photos are on the extreme and show clear softness/blur on everybody's screen, many photos are on the border, I have seen many times some people claim a photo is oversharpened and some people at the same time claim it is soft. Also sharpness can be technically defined as MTF, ans as such depends on your screen dpi.


I think it is the other way round. As sharpness is all depends on your eyes, your brain, and your own preferences, if you receive a comment saying that your image is not sharp, and you disagree, and most viewers agree with you, then you can choose to ignore that "unsharpness" comment and go with your own conclusion. I do not think you can tell other members to have the same monitor exactly as yours with settings exactly as yours before they can comment on the sharpness of your photos. Sharpness is in the eye of the beholder. Sid's investigation is futile from the get go IMO. And he also agrees with other that that particular image is not sharp enough, the same conclusion drawn by other members with different monitors of different resolutions.


BTW, I can use the same resolution as yours and if I set the contrast of my monitor low, yours image will still look not as sharp as that one seen on your monitor.

What image are you talking about?


I believe Arite has addressed that sometime ago. Histogram is not enough, IMO. One should check the RGB values of those areas. 255 is definitely white with no details. Anything above 247 give you pretty much the same results and same impression of blown highlights. But in the histogram, 247 is not clipped.

BTW, I think I read something written by Fabs somewhere sometime ago that critique forum is more like a poll. I think that's a good way to see it.

you can read values off a histogram, horizontal axis is intensity values.

arash_hazeghi
08-16-2009, 08:29 PM
We have one at the end of the page.

Sorry Fabs, I missed it :D it would be even nicer to have the one with more tones!!!

Desmond Chan
08-16-2009, 11:43 PM
Well I disagree, please read the other thread for more information, sharpness does depend on the screen.

I participated in that thread in case you do not remember. And I also disagree with Sid's definition of sharpness and provided my reasoning, which he responded with only his questioning of my ability to read. I believe you and Sid's definition on that thread are wrong in ignoring contrast. Without contrast, nothing looks sharp. Next time, look at an highly under-exposed photograph. No matter how high a resolution you have on your monitor, how high the resolving power your lens have, I doubt that particular photograph will look sharp to you. Key word being 'look". And as I have said, I can be using the same monitor as you do with the same resolution but just different contrast, and you and I could have different impression of sharpness. You likely disagree, but to me that is simply common sense.


What image are you talking about? What I say is not image specific. I think you think too hard.


you can read values off a histogram, horizontal axis is intensity values.Yes, you need to know the values. And you do not need to use a histogram to find out the values. You do need something else other than the histogram to tell you the values.


What I am trying to say is: I do not think anyone could tell others be careful when they want to comment on the sharpness of other people's photo because they could be using the wrong monitor and thus their opinions could very well be wrong. I do not see how anyone can tell other people what they see is sharp when their eyes tell them the image they are looking at is not sharp. Are you going to limit what other people can comment on now? That is ridiculous IMO.

Lance Peters
08-17-2009, 06:04 AM
Interesting thread - I think I agree with Desmonds reasoning in relation to sharpness - think it is more likely to depend on a Individual's preferences and vision. Everyone is entitled to their opinion and if it looks soft to the viewer I think they are quite within their rights to say that IMHO it looks a tad soft - you of course can choose to ignore their comment.
Most experienced BPN members would check the values before commenting on a image being over exposed I would think - personally I would comment "some area's look a little hot - best to check with your histogram"

Just my thoughts...

arash_hazeghi
08-17-2009, 06:19 AM
Interesting thread - I think I agree with Desmonds reasoning in relation to sharpness - think it is more likely to depend on a Individual's preferences and vision. Everyone is entitled to their opinion and if it looks soft to the viewer I think they are quite within their rights to say that IMHO it looks a tad soft - you of course can choose to ignore their comment.
Most experienced BPN members would check the values before commenting on a image being over exposed I would think - personally I would comment "some area's look a little hot - best to check with your histogram"

Just my thoughts...

Hi Lance, I agree people are entitled to their opinion, I never ever said they should not express their opinion, however it is best to learn about some facts on the side when we are commenting, this is why we are all here, to learn and receive constructive comments. There are some amazing photographers on this site and I have personally learned a lot from their techniques, like Al, Art, Fabs and others thank you all :)

Christopher C.M. Cooke
08-17-2009, 07:02 AM
There are times I agree and disagree but I have come to the conclusion that some images are for yourself and some must conform to the general rules of competent photography and only the experts can judge the second choice.

The experts are merely a group of folk who have (in their own mind) mastered the art and are therefore the baseline from which most of us work.

I love "some" of the "art" here but hate most of it, why? simple, I am firstly and lastly a lover of wildlife in its natural form and totally dislike the "artistic" virtues of heavily PP manipulated images, however, without a site like this I would never have learned even a fraction of what I needed to give me the ability to take images that I love but would never post here.

We decide what forum we compete in and rest assured many here are competing with each other for the kudos of compliments and criticisms and the massaging of their own egos instead of using this wonderful forum as a classroom where we are all faceless individuals, gaining the wisdom of the great artists of this incredible medium.
<o></o>
I doubt I will ever have an “Arthur Morris” hanging off my wall but I will have a little of Arthur Morris in every image that does hang off my wall and within every image that does will be a little Fabs, Axel, and so many other wonderful folk who have selflessly helped me along the way.
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That quite simply is why I am a member here, not to copy these folk but to learn from them.
<o></o>
I believe that that is also their aim and for that I thank them

Rob Miner
08-17-2009, 10:07 AM
I have a different feeling about BPN. I do not want to change anything including the intense discussions. Surly we all know that personal perception is personal. My use of the BPN is to learn. I will sometimes post a difficult picture (difficult for me) for comment and criticism. I truly need your expertise in solving the inherent problems. And I can truly say, Thank You all for the well meaning help and mean it.

Rob...............

P.S. Comments and criticisms are good. Help is fantastic!

Kiran Khanzode
08-17-2009, 11:32 AM
There's some good things on this forum and some bad things. Agree a lot with Christopher's views. Some of the attacking comments by a mod in a friend's thread (wildlife) really got me thinking whether this is a place to stick around or not. Almost feels like a virtual boxing ring here . Seen atleast 2 cases here where new members were put on the backfoot right away...as if to remind them of their position in the pecking order.

Sometimes, more than a histogram, one's eyes and vision can give a different impression about highlights even if they are not blown. Let's not try to be geeky(blindly follow some software or book) and ignore what your mind/eyes see.

One thing I really dislike is the obsession about the expectation of a "clean" background for every image taken in nature, in uncontrolled situations. How the heck is that going to happen ????????

Was reading a book last night. It had some lion pictures by Art Wolfe....images were taken in absolutely gorgeous light..but wait, the BG was cluttered....

Axel Hildebrandt
08-17-2009, 12:13 PM
There's some good things on this forum and some bad things. Agree a lot with Christopher's views. Some of the attacking comments by a mod in a friend's thread (wildlife) really got me thinking whether this is a place to stick around or not. Almost feels like a virtual boxing ring here . Seen atleast 2 cases here where new members were put on the backfoot right away...as if to remind them of their position in the pecking order.



Kiran, I'm wondering why you consider comments to be attacks. People on the forum try to help each other and different points of view are just that and you are free to agree or disagree. Productive criticism (is that what you mean by 'boxing ring'?) is what I value most on this forum. It is not personal, just people taking the time to give their opinions. I consider it a sign of respect to treat everyone equally and give one's honest opinion rather than a pat on the back only.

allanrube
08-17-2009, 12:13 PM
Kiran, I know where you are coming from with the background comments. However, I clean up my backgrounds some when I find objects that distract from my subject. I do like to show the environment when possible.

Some people get praise no matter what they do. Some people can post anything and several people will write the same positive thing they always say. However, I find less of that here than I do on other forums. I think that is just a fact of life - just like any large group has ins and outs.

I do think, however, I have learned a lot from comments I have received. There are bad tendencies I have that often escape me. When pointed out, however, I am less likely to repeat them. Sometimes I disagree with comments - but anyone would say you should be happy with your image.

With the expectations I have I can say I am quite pleased here.

Mike Moats
08-17-2009, 02:42 PM
If you are posting images that are outside of what most consider the proper rules of composition, DOF or clean backgrounds, it's helpful to state that with your post. If you wanted an image showing some of the BG, let us know your intentions. If you shoot a wild flower that is in a cluttery environment and you couldn't get any better BG, than it helps to let us know. If you put the image in the middle when most would put it in the thirds, let us know why you put it in the middle. Help everyone viewing your image to understand what you're thinking when composing. If these things are not brought to our attention then most would probably critique using the standard rules of comp to help out. Personally I stick to the rules of comp as from my experience it works the best nine times out of ten. Thinking out of the box is fine but I have to say in most cases people don't get it unless they have very artistic thinking, which I've learned from doing tons of art shows is a very small percentage of the population. Sorry Arash, it seems we've gotten of the track from your original post.:)

Sid Garige
08-17-2009, 05:31 PM
Arash,

I did spend considerable amount of time reading various articles and tutorials regarding this subject and I admit I am yet to understand the whole concept. In my experience this topic is very complicated and requires understanding of a wide variety of elements.
My histogram test on sample image from monitor to monitor is a proof that content of image varies considerably from monitor to monitor. If someone disputes it well they are entitled to their opinion and I respect that too. I don't know the complete answer yet and I will not comment or defend my opinion with "half knowledge".

what I can do for now is to limit my critics to composition and overall concept of image and not comment on sharpness and color tonalities.

arash_hazeghi
08-17-2009, 07:52 PM
Hi Sid,
Sharpness can be technically defined by the drop in the contrast difference of a step as measured by MTF. The scientific way to test this is to scan a standard MTF chart and display it on screen A at native resolution, then have a number of unbiased viewers view the image, and have them do the same for screen B. If, on average they see a difference, you can state that on average screen A is sharper than B. As such sharpness of a screen is related to its resolution (which is pixel density measured by dpi not the number of pixels as commonly used). Most of the current desktop screens between 20"-22" have a native size of 1600X1200 pixels so dpi is similar, however with new LCD technology there are some laptop screens available these days that have the same number of pixels on a 15" or samller screen, like the Lenovo that I use it's 15.4" and 1600X1080 pixels so an image on this screen will look sharper to an average viewer.
In adition to sharpness, contrast and colors vary between screens too, in fact much more than sharpness does.

Best,
Arash

Christopher C.M. Cooke
08-17-2009, 07:54 PM
From alanrube Some people get praise no matter what they do. Some people can post anything and several people will write the same positive thing they always say. However, I find less of that here than I do on other forums. I think that is just a fact of life - just like any large group has ins and outs.<link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CChris%5CLOCALS%7E1%5CTemp%5Cmsoh tml1%5C01%5Cclip_filelist.xml"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]-->

Now Alan, you would not be referring to "Artie’s" posts where his adoring disciples line up in alphabetical order to sing his praises would you? That is always obvious and I personally believe that in the USA Artie is the “Capo de Capos” of the Bird photographer’s Mafia.
<o></o>
I suspect that his disciples know that to critique the great one is to have one’s head bashed in on some dark night by one of his surplus to requirements 600 f/4L Lenses.
<o></o>
I have actually found fault with one of Artie’s posts, and safe in the knowledge that his reach has not (yet) reached our Antipodean shores I actually had the courage to post my critique prior to increasing my life insurance policy and heading for South Western Tasmania.
<o></o>
Sadly the truth be known it was only a spelling mistake and a minor one at that but I felt like I was Saint George and had finally slain the Dragon for I had found the chink in the armor of our doyen and sage King Arthur Morris.
<o></o>
Unfortunately, I have yet to find anything worth offering the great man in the way of photographic advice, probably because I still have to read the manual to help me change lenses and my idea of great composition is when I actually get the bird in the frame at all.
<o></o>
I am not heavily into hero worship but I know incredible competency when I see it and am happy to sit under the table and catch his (and many other’s) crumbs of wisdom when they fall and I can assure you that when I finally have my own work on display at the back room of some grubby bar somewhere in Melbourne probably called
<o></o>
“CHRIS COOKE THE PHOTOGRAPHER. HIS COLLECTION OF CONFUSED BACKGROUNDS, SOME WITH BITS OF BIRD IN IT”
<o></o>
I will make sure to credit Artie on my embossed invitations as I could not have done it without him (and many others here)
<o></o>
Unfortunately if Artie reads this it will probably make him sick.
<o></o>
Sorry Artie

We do not have to immitate the experienced folk here but sift through their invaluable advice and use the bits of it that suit our needs and I can assure you that I have never felt intimitated here and at no time has any critique gone to waste, some of us are different and that is the way of art, I have yet to understand Picasso but if offered one cheaply my answer would be the same as to any advice given here, "thank you very much"

Ákos Lumnitzer
08-17-2009, 08:13 PM
I agree that monitors will render an image differently and perhaps those settings may (or do) affect perceived sharpness. However, as long as it is a sharp image then we should be able to pick up this perceived sharpness by looking carefully. I am no tech head that is for sure though, and I am not interested in how many nanometers of pixel intensity or density or whatever will differentiate between sharp and unsharp. See? I am babbling **** already regarding technical stuff about I have no clue. :D

On a different note, while some people may consider some comments a little off putting, this is by far the most friendly on-line forum I have ever had the pleasure of being a member of and this is the ONLY place I actually paid a membership. Not that what I am saying is of significance as I am really a nobody in the world. I am just making my point heard. :) At the same time, when I comment, I like to use a few emoticons especially when I reply to a newer member's images so as to try and make sure that the constructive critique is given with a smile and my perhaps negative input to the overall presentation is not received in the wrong manner.

I guess if someone gets upset that they don't get pats on the back, then there is always the exit or log-out button. :)

Axel put it very nicely in pane 12 and I would (as should any member) never take anyone's comment as an attack.

Sid Garige
08-17-2009, 09:47 PM
Hi Sid,
Sharpness can be technically defined by the drop in the contrast difference of a step as measured by MTF. The scientific way to test this is to scan a standard MTF chart and display it on screen A at native resolution, then have a number of unbiased viewers view the image, and have them do the same for screen B. If, on average they see a difference, you can state that on average screen A is sharper than B. As such sharpness of a screen is related to its resolution (which is pixel density measured by dpi not the number of pixels as commonly used). Most of the current desktop screens between 20"-22" have a native size of 1600X1200 pixels so dpi is similar, however with new LCD technology there are some laptop screens available these days that have the same number of pixels on a 15" or samller screen, like the Lenovo that I use it's 15.4" and 1600X1080 pixels so an image on this screen will look sharper to an average viewer.
In adition to sharpness, contrast and colors vary between screens too, in fact much more than sharpness does.

Best,
Arash

Arash,

Agree. I did run into same info on MTF link posted by BPN moderator. I agree with you. As a personal practice as you suggested I decided not to comment on sharpness and color tone related issues.

-Sid

WIlliam Maroldo
08-17-2009, 10:00 PM
This is far too complicated. An easy test, to rule out the monitor being the problem, is simply see if any images on BPN have sharp edges and good detail resolution. If they all are "soft" it is the monitor. If some(even one) is sharp and shows good detail, then it is not the monitor. regards~Bill

arash_hazeghi
08-17-2009, 10:02 PM
Hey Sid,
I think it is still fair to comment on sharpness/colors despite this issues, I just wanted to point out that one should not just pick too much on these points when other aspects of an image are excellent. Ironically I commented on more sharpening on a great photo a few hours ago :D Sometimes you can make and excellent photo even better by subtle adjustments :)

Roger Clark
08-17-2009, 10:07 PM
A few notes on perception of sharpness.

The idea was put forth the contrast has a significant effect on apparent sharpness. This is right on and I believe is probably the main effect Arash is seeing. The basic proof of this concept is that fact that people call unsharp mask sharpening. Not only does unsharp mask not sharpen at all, but it in many (most?) cases reduces sharpness! Unsharp mask gives the illusion of sharpening by increasing edge contrast. This is called acutance.

I'll refere people the the "Important Sharpening Information!" thread:
http://www.birdphotographers.net/forums/showthread.php?t=18534&highlight=important+sharpening+information

Similar effects are likely happening in LCD displays, decisions different manufacturers has decided in the manufacture of their monitor, and then modified by users of those monitors by adjusting contrast.

The different in dot-pitch between monitors, whether LCD or CRT is small in comparison to the contrast effects.

Roger

Sid Garige
08-17-2009, 10:35 PM
A few notes on perception of sharpness.

The idea was put forth the contrast has a significant effect on apparent sharpness. This is right on and I believe is probably the main effect Arash is seeing. The basic proof of this concept is that fact that people call unsharp mask sharpening. Not only does unsharp mask not sharpen at all, but it in many (most?) cases reduces sharpness! Unsharp mask gives the illusion of sharpening by increasing edge contrast. This is called accutance.

I'll refere people the the "Important Sharpening Information!" thread:
http://www.birdphotographers.net/forums/showthread.php?t=18534&highlight=important+sharpening+information

Similar effects are likely happening in LCD displays, decisions different manufacturers has decided in the manufacture of their monitor, and then modified by users of those monitors by adjusting contrast.

The different in dot-pitch between monitors, whether LCD or CRT is small in comparison to the contrast effects.

Roger

Roger,

Just realized Clarkvision is your website. Excellent resources and very very informative.
Thanks
Sid

arash_hazeghi
08-17-2009, 11:51 PM
A few notes on perception of sharpness.

The idea was put forth the contrast has a significant effect on apparent sharpness. This is right on and I believe is probably the main effect Arash is seeing. The basic proof of this concept is that fact that people call unsharp mask sharpening. Not only does unsharp mask not sharpen at all, but it in many (most?) cases reduces sharpness! Unsharp mask gives the illusion of sharpening by increasing edge contrast. This is called accutance.

I'll refere people the the "Important Sharpening Information!" thread:
http://www.birdphotographers.net/forums/showthread.php?t=18534&highlight=important+sharpening+information

Similar effects are likely happening in LCD displays, decisions different manufacturers has decided in the manufacture of their monitor, and then modified by users of those monitors by adjusting contrast.

The different in dot-pitch between monitors, whether LCD or CRT is small in comparison to the contrast effects.

Roger

Yup contrast is very important too. Some of these new notebook screens that have come to the market have really crazy tight pitch though, compared to desktops (pixels smaller by 2X) which can cause headache if you read too much text at default font size :eek:, the Lenovo is actually low contrast and relatively dim but the sharpness is amazing. When I load the pics that I post here on BPN on the Lenovo screen they look oversharpened to my eyes. I had not seen such a big difference between desktop LCDs though, probably contrast wins there, and different people have different tastes too some may see a contrasty image as more sharp. Basically I am happy as long as I see some feather detail and not motion blur.