Sharpness .... discuss

[edmund]

I'm putting this here, rather than in the 'Talk about....' forum as I'm a happy 10D + various lens owner.
Now, apart from wanting to learn from the other good folk who inhabit Pekka's world, I guess most of us are gearheads to one degree or another - that's why we're here, right? We want to get the most out of the equipment that we're fortunate enough to own.
But this whole issue of 'sharpness'.... I've been getting overexcited about this when I've been doing contrast-and-compare tests with my various lenses (I have the 17-40f/4L, 28-135IS, 50f/1.8 and the 70-200f/4L. I love 'em!).
I've spent a lot of hard earned cash on this stuff and I'd like to be able to double-check with my fellow enthusiasts that all is as it should be with this kit. If this post is going anywhere, it's wanting to know what 'tack sharp' means to each of you. Is it 'tack sharp' when printed as an 8 x 10? Or is it 'tack sharp' when viewed at 100% crop in Photoshop? How do you know whether your lenses, and camera, are performing as you feel they should? There's an article on photo.net about 'Gigapixel images' where you can blow up a tiny corner of an image and all the detail is there! It's awesome. Costs gazillions for sure but... What is reasonable to expect from a 10D with a chunk of L glass on the front? I've seen some of these sites where they have MTF or SDQ or some other kind of 'objective' analysis of lens performance BUT I'd be really interested to hear what you good folk consider a subjective benchmark for image quality.
Thanks.

[csondagar]

I am a newbie when it comes to photogaphy. Some of my shots when I view them at 100% looks sharp to me but when I have submitted to forums I have been told that the photo is not sharp enough. I also would like to understand what 'sharpness' means to others, and how they evaluate sharpness of an image.

[tumb]

This is a very good subject. I usually tend to sharpen too much, but I think that may be a beginner thing, and maybe I'm taking a shortcut to try and make my images better and sharpen too much because of my present lack of knowing what else to do. Learning is fun though.

Sometimes I get lucky and improve an image by processing, but more than once I have worked on an image for a couple hours and get it where I think it's just right, then compare it to the original image and the raw data out of the camera actually looks better. :?

[dhbailey]

At the risk of sounding trite, I feel that sharpness is in the eye of the beholder. Where is it written that a great picture has to be sharp? Or to what degree an image must be sharp before it is agreed by all as being sharp?

Duke Ellington said about music "If it sounds good, it IS good."

I feel much the same about pictures -- if I like the way it looks, then to me at least it is a good picture. If it captures what I want then I have shot it perfectly, no matter what anybody else says. And conversely, if the picture doesn't capture what I was trying for, as clearly as I was trying for, then also it doesn't matter what anybody else says, it is a failed picture.

Sharpness with digital cameras seems to be a combination of 2 factors: how well you focus (which is a factor of the quality of the glass as well as our eye's ability to focus as we want) and the sharpening software built into the camera. Focusing can be (and needs to be) practiced. AutoFocusing needs to be practiced with as well as manual focus, so that we can get the shot we want with either manual focus or with AF. We can't do anything about the sharpening that may be done by the camera (except to keep our parameters set so that it is at a minimum).

I am trying to treat my DSLR just as I used to treat my 35mm film camera, and trying to learn my DSLR so that I can get the same shots as if they were being burned onto film with no processing by the camera. I have begun to take my pictures with Parameter 2, so that the camera does as little post-processing as possible. Currently I am shooting RAW +L-jpg to see what the differences may be between those formats.

I, too, have found that I am often happier with the original picture than with any sharpening I try to do with PaintShopPro or PhotoshopElements.

Ultimately, I realize that I have to practice with the camera more to get the shots exactly as I want them every time. Then post processing can be kept to an absolute minimum, which to my way of thinking for most pictures would be the best way to go.

In music there's a phrase when somebody doesn't play their part exactly right "That's okay, we'll fix it in the mix." That often works, to a point. In other words, the flaws are minimized and buried in the post-processing, so the released product is acceptable. But that doesn't change the fact that the part was played improperly. The same is true of digital photography -- we should rely as little as possible on post-processing to improve our pictures and should practice more to capture just what we want in the original shot.

And that includes the degree of sharness we want to achieve.

[Sam North]

I guess most of us are gearheads to one degree or another - that's why we're here, right?
Maybe most, but it's certainly not why I'm here.

We want to get the most out of the equipment that we're fortunate enough to own.
Yes to that, but image sharpness is quite relative at the end of the day when you stand back and admire the print. On the other hand, if someone wants to get nose grease on it, then perhaps they're missing the point.

we should rely as little as possible on post-processing to improve our pictures and should practice more to capture just what we want in the original shot.
There's a lot of truth in that, although digital's contrast problems mean there are times when, if you're shooting landscapes for example, you'll have to shoot RAW to help you expand the range.

In fact, there are occasions when it's actually impossible to get what you see in one shot. You have to shoot two, maybe more, and use various techniques to arrive at the most true-to-the-original print. In effect, this means that image-editing can take you further than you could ever go with a one-shot image.

Sam

[Jesper]

Norman Koren has a very elaborate discussion about what sharpness is and how you can measure it: http://www.normankoren.com/Tutorials/MTF.html - note, this goes into a lot of mathematical detail.

He also wrote software called Imatest (http://www.imatest.com/): "Imatest™ is a suite of programs for testing the sharpness and image quality of lenses, digital cameras, digitized film images and printers, using inexpensive, widely available targets."

So if you really want to test the sharpness of your equipment in an objective way, have a look.....

The resolution of monitors is not very high, which makes a monitor a poor instrument to judge the sharpness of a photo. Prints always look sharper than images on your monitor, because a printer can print at much higher resolutions than what a monitor can display.

I have a Sony 19 inch CRT monitor myself. My brother has a laptop with a very high resolution LCD screen. When I saw my photos on his laptop, they looked much sharper than on my own CRT monitor. LCD monitors have very good sharpness (especially if you connect them using the digital interface - DVI). On the other hand, LCD monitors are not so good at reproducing colour as CRT monitors.

[phili1]

Ok to me a lens is sharp if it can pass this test.

I bring it into photo shop and I use the contoll+ to zoom in on it. If I can zoom 5 to 7 times and still keep a sharp look then I know it is good.

Example: I recently bought the Tamton 200-500 lens. I went to my favorite spot and took some ok shots with it. I posted these shots and got comments that they were soft, so this set the whells spinning.

I went out again and tripod mounted it and took 25 shots. Results: 3 shots were ok, 2 were so so and 20 were blurred.

The Ok shot only zoomed 3 time and it blurred the 2 shot I got to 2 and the rest at 1 were blurred. This told me that something is wrong with the lens I have. My Heron shot I could zoom 7 times.

Now you ask what the heck does zomming have to do with it. Well it tells you how far you can blow up a picture to print. If you get to 3 then 4 x6 might be the sharpest, by 7 your looking at 16 x 20 +.

Anyway all your lenses get rave reviews on Miranda and I know someone who has the 17 to 40 and will bitr your head off if you say anything bad. The only one that took hits is the 28 - 135 50 % said sharp and the rest were divided.

As far as chart test go, it's allot of bull and the reason I say that is if you take a lens and shoot a chart you have to know what you are doing or you can get false results. Let's say you test your lens and it tells you that it is front focusing. So what, no lens is perfect and each one different. On the chart it will show you that it is off by what a 1/4 to a 1/2 inch, so you focus on the eyes, the back of the head a F4 will be out of focus, wow throw this lens or Camera away its no good.

Enjoy your lens and if they please you then that is all that counts.

[Andy_T]

This might well turn out a very interesting thread 8)

I, for one, love to sharpen (not too much!) my image to get that 'crisp' look.

Actually, I think it was one of the happiest days in my life when I first tried out USM in Photoshop. I didn't know it was going to make a difference, and boy was I impressed!

Since then, I've included it as last step of my workflow (RAW, convert with BreezeBrowser to TIFF, touch up image in PS, SAVE, resize, sharpen, save as JPG). If I have some time I'll try to do some home work and post an image where one half is not sharpened, but the other is what I think a sharp image.

It certainly improves viewing the picture on the PC, for printout, you have to experiment with the optimal setup.

But the quality has to come from the lens. If the image is not sharp or out of focus in the first place, then no amount of USM is going to make the photo sharp.

Best regards,
Andy

[Andy_T]

Ok to me a lens is sharp if it can pass this test.

I bring it into photo shop and I use the contoll+ to zoom in on it. If I can zoom 5 to 7 times and still keep a sharp look then I know it is good.


Phili,

what % resolution does that make?

My observation is that the picture is opened at a different size initially depending on the size of the picture and your monitor.

When I open a 4 MP file on my laptop, PS LE 5.0 opens it at 33.3% size.
Zooming in 5 times takes it to 300%.
That's quite some magnification :shock:

On my desktop PC, the picture is opened at 50% size, and taken to 400% by zooming in 5 times.

Best regards,
Andy

[nosquare2003]

I, for one, love to sharpen (not too much!) my image to get that 'crisp' look.


I've just done the opposite in Photoshop. "Sometimes" I like my portrait photos to be soft and less saturated...it looks more natural to my eyes :P (Edmund, sorry for off-topic.)

[Scottes]

I like to sharpen as much as *I* feel is possible without it looking unnatural. I've got years of experience doing this and I think I'm pretty good at it, yet I manage to learn new things all the time.

Post-processing an image is very subjective, yet there are thresholds that are easy to cross (over-sharpening), and other times it's easy to be too far away from a threshold (under-sharpening). That middle ground is what you need to aim for, and that's the area of subjectivity. If it looks good to you then it is good, but that doesn't mean that someone else couldn't do a better job.

If you're into digital photography then it behooves you to learn how to post process. ALL images, digital or print film, get processed. Whether you do it, the camera does it, or a lab does it the image still gets processed. IMHO you'll be better off if you learn how to do it well, as it keeps you in control.

There's a "sticky" thread in Post Processing containing a number of tutorials from a number of people. Alas, there is not yet one on Sharpening, though I've been meaning to write one for the last 6 months at least. But sharpening is just one step in post processing, so check out the tutorials.


If you wish to get a good idea about a certain shot, post a "challenge" in the Post Processing forum. There are several of us here who will take an image and process it, describing our steps. It's often very stimulating, as several people can post-process an image and come up with completly different version, all of which are good or great. Other times different people will take totally different routes and achieve the same look. It can be interesting.


There's no doubt that it all starts in the camera, though. Get it right when you shoot and the final post-processed image will be excellent. Post processing can fix some things to a degree, but it's not going to salvage a bad shot.

[Scottes]

I, for one, love to sharpen (not too much!) my image to get that 'crisp' look.


I've just done the opposite in Photoshop. "Sometimes" I like my portrait photos to be soft and less saturated...it looks more natural to my eyes :P (Edmund, sorry for off-topic.)

Still a form of sharpening, really. But you might want to take a look at the Tutorials in Post Processing. There's one in there by gmitchell on how to achieve a "soft focus" look using Photoshop. Take a portrait and sharpen it a bit, then apply the soft focus look. It's can be very very nice.

[JX]

I agree with dhbailey I feel that sharpness is in the eye of the beholder. and what like to add is that it also depends on the subject. For portrait work I think a soft focus is more flattering. For landscape, sports action I think sharpness is critical.


I also agree with both Andythaler and nosquare2003. I use Photoshop’s Camera Raw to process the raw file then in Photoshop sharpen with USM or soften with Gaussian Blur depending on the subject.

But I think the most important point is to start witha photo that is correctly exposed and in focus.

[chris.bailey]

This is indeed an interesting one as there are two trails - the sharpness (whatever that means in a digital world) produced by the camera and lens (I think that is what Edmund was most interested in) and the post processing involved in Photoshop. It is difficult to seperate these two threads as post processing is a significant part of the process (especially if you do no in camera sharpening of jpgs or shoot in RAW).

To my mind/eye the level of sharpening applied should enhance the image based on the print size being produced. For me the sharpening level should be subtle when printed at the intended size which means going a little too far when viewed on the screen. If anything I am a little conservative.

Within any one persons 'taste' as to the right degree of sharpening, a so called sharp lens will allow more USM to be applied before it starts to look un-natural. Further, the 1D MkII tends to produce softer out of the camera images than a 10D BUT the data allows a greater degree of USM to be applied and the end result is a shaper picture. I was initially a little disappointed with the images from the MkII until I had tweaked my workflow to suit.

What most of us refer to as 'tack-sharp' is based on our individual experiences of what is less than 'tack sharp' and is wholly subjective. I know what I think is 'tack-sharp' when I see it but that may mean something else to another viewer. I recently did a portrait shoot for some friends and did half a dozen 8 x 10's that I thought were nice but not quite right (this was one of the first sessions with the MKII) so I went back and oversharpened them to my eye even to the point where I thought they were overdone in the prints. My friends much preferred the second set and thought I had softened the first set.

There is no right or wrong answer and yes I am sure you can objectively measure sharpness (heaven forbid) but I would really not want to. What I do want is a set of equipment and a workflow that every now and then lets me produce an image that I look at as it comes out of the printer and think WOW. Just like that one good shot you play on a round of golf, to be that makes it all worth while!

[JX]

chris.bailey wrote
Further, the 1D MkII tends to produce softer out of the camera images than a 10D BUT the data allows a greater degree of USM to be applied and the end result is a shaper picture.

Chris are you comparing the Mark II raws to the 10 D raws?

I have a ID Mark II, and have used a 10 D. I did a side by comparison. I used the same lens on both bodies and identical lighting. I tried to keep the camera setting as close to each other as possible. The Mark II JPEG images were better. I must admit that "better" was a bit of a disappointment considering the price difference between the two cameras. I was actually expecting a big difference. However, for sports and action photography the Mark II is clearly superior.

Unfortunately, I did not do a comparison on the raw files from each camera. 1D Mark II owners who also have 10D or 20D what do you think?

[phili1]

There you go how many different variations did we get.

I know the magnification is allot byt I use it as a test, if it blows ujp 4 to 7 time I kn ow how far I can push the printing. BUt it is like everything else in photography it is subjective.

[aam1234]

For me, as a novice, and with the parameter set to +2 sharpening on jpeg, I'd like to say that if I look at a photo and say "it doesn't need USM" then it's perfectly sharp. Sounds confusing I know, but as somebody said above:

Duke Ellington said about music "If it sounds good, it IS good."

[phili1]

Well with all kidding aside I find that my 20D is just fine out of the Camera and the most tweeking I have had to do is Levels. Everyonce in a while it needs sharpening and I use Fred Mirandas Intellesharpen. Now that I have Adobe CS I will use there raw conversion and it lets you adjust every aspect at a greater level then all the other program.

But I do take some marginal shots that need it.

[edmund]

One of the things I was wondering - when I started this thread - was: how can I be sure that a lens I have is a 'good' copy? Talk about this lens being 'tack sharp', that lens being 'soft' .... how do I know what is tack sharp and what is a bit soft? It's subjective, right?? I really love this gear I'm fortunate enough to have but naturally - I hope! - I'm wanting to know if it performs as it should.

[redbutt]

One of the things I was wondering - when I started this thread - was: how can I be sure that a lens I have is a 'good' copy?

Mount the camera on a tripod and use a shutter release cable to take some shots at different f-stop settings under controlled lighting. If you see that the shots are crap when shooting in "ideal" conditions, then you have a bad lens. Of course you'll need to do this will all of your lenses to have some form of control group. And for good sceintific measure, you should take control shots with a "known good" lens.

But, ultimately, if you like the pics your taking, then your stuff is fine.

DB

[phili1]

Edmund. There is no set system for lens quality. Men write rviews on lenses and we sometimes prove them wrong, at least to our selves.

The perception of a lens being sharp is in the eyes of the photographer and each of us has there own perception.

If you take a photo at 4 mega pixels and you can blow it up to 13 x 19 it is super sharp. If you take a photo a 4 mega pixels and all you can get sharp is a 4 x 6 then its not sharp.

Four people can buy the same lens and get four different results. That does not make the lens bad.

Chart lens test can't tell you anything no matter what anyone says and the reason why is it will tell you within 2 inches weither it is sharp or not. IN most cases you need to know how sharp it is within feet.

A wide angle lens should give you a very large DOF and a t f8 it should theoreticalaly be from 20 feet to infinity and at F16 even greater.

a 17 to 85mm lens should give zt f16 a wide range of in focus at 17 but at 85 ist smaller.

A telephoto should give less DOF as you climb the mm spectrum.

So if the lens is giving you pictures to your satisfaction then dont question it all you will do is confuse yourself.

Do you like the pictures your are getting, that is what counts.

All the lenses you have are quality lenses, you can't get much better, some people say the Tamron 28 to 75 out performs Canon 17 to 40 but I can't tell the difference in picture quality. I like the Tamron nad a friend of mine loves her 17 to 40 Canon.

Like I said go to www.fredmiranda.com, go to reviews look up your lenses and read the different perceptions of the same lens.

I think what you have to do is shoot with your lenses, look at your photos and if you like what you got you have sharp lensed. Just make sure its not you and not the lens. As good as we think we are, even the best lens scan give bad results if we do not use the best tech.

[chris.bailey]

chris.bailey wrote
Further, the 1D MkII tends to produce softer out of the camera images than a 10D BUT the data allows a greater degree of USM to be applied and the end result is a shaper picture.

Chris are you comparing the Mark II raws to the 10 D raws?

I have a ID Mark II, and have used a 10 D. I did a side by comparison. I used the same lens on both bodies and identical lighting. I tried to keep the camera setting as close to each other as possible. The Mark II JPEG images were better. I must admit that "better" was a bit of a disappointment considering the price difference between the two cameras. I was actually expecting a big difference. However, for sports and action photography the Mark II is clearly superior.

Unfortunately, I did not do a comparison on the raw files from each camera. 1D Mark II owners who also have 10D or 20D what do you think?

Both RAW or JPG (I leave the MKII jpg processing settings at low) the out of the camera image with the same workflow will leave you wth a better image from the 10D because the MKII data needs and will take more post processing (if all that makes any sense). Adjust your workflow and the difference is significant.

[photofinish]

One thing I've noticed in my limited travels as a photo-taker is that no matter how much time and effort I put into the post-processing and USM, if my eyes are tired when I do this, sometimes the next day I find myself asking 'what was I thinking'! :wink:

[Jon, The Elder]

Tremendous amount of rhetoric in the previous posts.

Heres a real scenario. Shooting outdoors at a "hunt class" horse show.
Horse and rider about 150' straight across from me. Bright gray day.
300d and my trusty 28/135.

Experience told me that the horse/rider combo were about 3' "thick" so I set the aperture to 6.3 and it was bright enough to give me a quick shutter speed. The background was 5-7 feet beyond the horse, and sloped up and back (green grass + small pines).
Centerpoint focus on the riders hip/thigh which put me dead-on the center of the horse/rider combo.

In PS I had 5 or 6 sharpening tools to use. All the way from the native PS stuff up to Fred Mirandas and a few private methods I use.

I had a certain "look" I was trying to achieve which included the horse/rider heads. I had taken care of the basic 10' x 10' key subject area with the camera/lens settings. A little judicious sharpening and viola,
I had the "look" I intended. The check for $125.00 from the riders sponsor told me I was right.

To make a short story longer - I have no set formula and I am not much a believer is those that do.

Good Shooting to all

[Andy_T]

I had a certain "look" I was trying to achieve which included the horse/rider heads. I had taken care of the basic 10' x 10' key subject area with the camera/lens settings. A little judicious sharpening and viola,
I had the "look" I intended. The check for $125.00 from the riders sponsor told me I was right.


Setiprime,

now we all want to see that photograph.

The way you describe it makes my mouth (er ... eyes) water :D

Best regards,
Andy

[nosquare2003]

Still a form of sharpening, really. But you might want to take a look at the Tutorials in Post Processing. There's one in there by gmitchell on how to achieve a "soft focus" look using Photoshop. Take a portrait and sharpen it a bit, then apply the soft focus look. It's can be very very nice.

Thanks. I will have a look there.

[amorrison]

One sort of side question. If you capture an image from the lens as sharp as possible, one would think you then have captured the most amount of information that the lens is capable of delivering. Then, if you apply any softening, you reduce the total information in the image. There must be a difference between the sharpness added by photoshop for instance, and sharpness added by a lens. Common sense would lead you to think that post processing could not increase the total amount of information in an image right? It could decrease it, as in softening it, but not create more information than was in the original image. So is it really sharper, or does it just appear to be sharper when post processed?

[Jon]

I think you're looking at two different things here. The amount of information in the picture would be an indication of the resolution, not "sharpness". Sharpness is really just the tonal gradient at an edge. Increasing the gradient/sharpening the image won't add real detail to the picture; it may make it easier to see detail that's there or, if carried too far, introduce artifacts and "false" detail.

[maderito]

Sharpness is really just the tonal gradient at an edge.

I like that definition.

"Tonal gradients" would include contrasts between light and dark as well as between colors (their hue, brightness and/or saturation). Thus one approach to improving perceived sharpness in an image focuses on enhancing color contrast rather than relying solely on standard ege sharpening. Some of the sharpness seen in expensive lenses is a function of their improved capture of color contrast.

[Jon, The Elder]

Very good thread for me - I just hope the originator EDMUND - got something out of it !!