To Sharpen or not to sharpen ~ that is the question...

[David deSousa]

Over the past six months or so I have had one fundamental post processing focus: sharpening. Although I wanted to puckishly fold Shakespeare into my title, the question is not actually whether or not to sharpen, but how much, and using which method(s).

Most of the exceptional digital photographers I have seen, read, or have spoken with, rely on some sharpening, even very accomplished impressionists will do it. The upshot seems to coalesce around two seemingly disparate requirements: One is relevant to the overall message of the image; form, light, color, and content; the story. The other is more to do with post processing technique; never to let it be seen (be detectable). The latter has to do with a general philosophy regarding post processing, applying the same admonition. If it shows, then it detracts, sometimes fatally, to the entire effort.

One of the excellent photography tutorials available is on this website called "Understanding Sharpness." This takes us through the fundamentals of sharpening; what it is and how it is done. My question is less technical, more subjective.

We all know that white (or dark) halos are one of the unpleasant artifacts of over sharpening, which can kill an image on delivery. It takes some very, very good content in the image to overcome this and other exposure and processing errors.

The impression of infinite depth of field is another, where the overall image acutance is another bane of global sharpening, lending an unnatural impression or an unbelievable quality that almost hurts your eyes to look at.

And there are more.

I wanted to throw this topic out to the CiC community for comments from one and all. I know there must be a lot of questions about this subject; and there may be some who have answers they can share with us.

So, I will cast one of my own guinea pigs into the ring for sacrifice. Is this image over sharpened? If it is to your eyes, can you say specifically why, or better yet what to do about it. Or, was it sharpened at all? How can you tell?



Cheers,
David

[Shadowman]

I'll take a guess and say that it hasn't been sharpened, only because the image looks unsharp throughtout the entire frame. I believe there was some post processing, contrast or noise reduction however.

[carregwen]

I'd say it has not been sharpened. Partly because John just said so and I trust his fine judgement and partly because it doesn't look sharp.

Your image original is 750px long-side. You can post at 1024px. It still gets rescaled to 700px, but you can view it in a new tab/window of the browser at 1024px. It makes judging things like this easier.

[David deSousa]

Hi John,

Well, thanks for the guess. It is too soon in the game to tip my hand, but you touch on a similarly oriented plague, which is processing for uploading to achieve maximum perceived acutance or the perception of sharpness. This image is an example, it is partly why I chose it. In it's original size it is sharper. Resizing degrades that aspect. The choice facing us all is what to do. Sometimes it seems like a crap-shoot. This one probably should have had some post reduction sharpening. It didn't get it.

Thanks for my part,
D.

[David deSousa]

OK, Rob, I'll try it.



There, that seems to have worked.

The point of my thread is not my picture though. I have made images that are over sharpened, some not. I see "over sharpened" images everywhere on the Internet, here and elsewhere, even from people who are supposedly immune. The thumbnails on CiC look way over sharp to me most of the time. I don't remember one in print in a gallery though.
D.

[ascott]

It's very hard to tell at this size of pixels, David but I'm going to stick my neck out and say that it has had some sharpening as the FG surf looks to have sharpening artifices and the near rock face looks bright which can happen when sharpening for web.
I always sharpen on a different layer so I can paint back anything that I don't want on a mask layer, that way I have control over how the finished image is going to look. If you shot in RAW like I do then this processing is best IMO, in camera sharpening is OK if you FTP shots to a clients.

[carregwen]

OK, Rob, I'll try it.
D.

It looks the same on the page here. But when you view it in a new window it looks sharper with the new version.

[David deSousa]

Roger that, Alex; about layers. Your way is my way too. This is from RAW, but without special effort to optimize perception of sharpness for jpg reduction. I don't do in-camera sharpening. Normally I do a final light sharpening after reduction ~ a three-step process basically. Not this time. The image, this one, has tell-tales everywhere, especially if you zoom in on a screen shot.

Thanks for your input. Any more advice?
D.

[ascott]

I save all my images as TIFF files without any sharpening until I know what the final output is going to be, as each will need different amounts of sharpening.
For web I give it three or four passes of Smart Sharpening at:
amount:180
radius:0.2

[David deSousa]

I save all my images as TIFF files without any sharpening until I know what the final output is going to be, as each will need different amounts of sharpening.
For web I give it three or four passes of Smart Sharpening at:
amount:180
radius:0.2

That is a good method. Sounds too easy (smile). I use TIFF only out of DxO, so I can tell them from ACR = PSD basically. My RAWs go to ACR these days, where I make standard adjustments with some sharpening, etc. and then open them in Photoshop. I then save in PSD. When I revisit the RAW file I always kill the sidecar anyway ~ fresh view and all that.

What I was trying to evoke in this thread was more nuanced viewpoints about over sharpening vs. image content, and if others wanted to take it there, about value of post processing in general. Maybe too much from one thread, eh? I guess if the sharpining issure were a pattented 1-2-3 kind of thing then it wouldn't have such mystery, at least for me.

D.

[Shadowman]

That is a good method. Sounds too easy (smile). I use TIFF only out of DxO, so I can tell them from ACR = PSD basically. My RAWs go to ACR these days, where I make standard adjustments with some sharpening, etc. and then open them in Photoshop. I then save in PSD. When I revisit the RAW file I always kill the sidecar anyway ~ fresh view and all that.

What I was trying to evoke in this thread was more nuanced viewpoints about over sharpening vs. image content, and if others wanted to take it there, about value of post processing in general. Maybe too much from one thread, eh? I guess if the sharpining issure were a pattented 1-2-3 kind of thing then it wouldn't have such mystery, at least for me.

D.

I think this discussion can go a couple of ways.
1. Do you sharpen if you want CIC?
2. Do you sharpen if you expect your audience to be novices or pros?
3. Do you sharpen because you think the image needs it?
4. Do you sharpen because the image is just out of focus?

[arith]

I thought dslr's were different beasts to film camera's and demosaicing causes blur. Different dslr's have different resolutions and can only be sharpened so much.

I use a different sharpening tool to most, I don't even do capture sharpening but sometimes apply a high pass filter to a resized image. The tool I use is more commonly used by those that like extreme effects, but I've learned to tame it.

I thought I would do an example

this is unsharpened:




Deconvolution only after cleaning noise





Normal Topaz sharpening





I'm just about seeing some artifacts creeping in the last but I always sharpen assuming enlargement to about A2 or A1 size,
even if I don't

[ascott]

IMO all images from a RAW file will need some sort of sharpening to bring the best of it out. The end results depends on the technique used and the person sitting in front of the computer, like all things in PS, they're numerous ways to do the same thing.
If an image isn't sharp to start with due to camera shake etc then bin it, no matter how good it is.

[arith]

I thought it was sharp actually; but it is 1.3 seconds on a monopod. I didn't think you would ever be able to read the text from so far, I could be wrong though. I was just showing there is a difference between undone and done. cheers

[ascott]

I thought it was sharp actually; but it is 1.3 seconds on a monopod. I didn't think you would ever be able to read the text from so far, I could be wrong though. I was just showing there is a difference between undone and done. cheers

Wasn't meaning your image Steve was answering John's last question. Sorry for the confusion.

[arith]

Yes but since you mentioned it, it could be blurred due to camera shake. Should take a tripod with me. cheers

[David deSousa]

I think this discussion can go a couple of ways.
1. Do you sharpen if you want CIC?
2. Do you sharpen if you expect your audience to be novices or pros?
3. Do you sharpen because you think the image needs it?
4. Do you sharpen because the image is just out of focus?

This is an interesting comment, John. I can answer #2 and #3 for myself and perhaps others to some degree.

Of course I sharpen because I think the image needs it. I think everyone does, n'est-ce pas? But the reasons I may think sharpening is needed vary all over the map.

The first reason is because I work directly from RAW. I know there is an inherent sensor phenomenon called mosaicking that can lead to an apparent loss of acuity in the overall image. This has nothing to do with focus, motion blur, camera shake, or diffraction limit. In-camera jpg algorithms handle that in some fashion automatically, besides file compression, but with RAW you have to do it manually (or get to do it).

If the image lacks acuity for those reasons above, then there is no correction for them. Not with film, not with digital. What we can do with digital post processing is reduce the impression and or perception of them in the final output. We can create an illusion of "sharpness." That ability, I think, leads us to overdo it, i.e. over sharpen. Sometimes the in-camera jpg algorithm makes a mistake as well, leading to visual artifacts ~ which can be cleaned up BTW.

My question really has nothing to do with why we sharpen, it has to do primarily with over sharpening and how over sharpening is perceived, or made known to the viewer of the end result. We often read in critique that the image is over sharpened, but the commentator rarely says or describes why he or she says it it over sharpened ~ not that they are wrong, necessarily.

And now what about under-sharpening, or not sharpened enough or at all? I chose my example image deliberately for this thread because it represents a scene that has haze in the air. It is a tumbling surf scene after all, and you can clearly see it off in the distance. This is water vapor in the air, which causes refraction, and leads to an overall loss of apparent acuity and contrast. This is what was real at the time of exposure (all I had on the lens was a UV filter). I know full well that attempting to rid the image of these issues would result in an impression of over sharpening, even if I avoided the artifacts by process, or edited them out afterward.

Perhaps a better way to ask my question in part is would you add more sharpening to this image (past RAW sharpening)? And if not, would you put it up for critique? Why?

Thanks for you comments, John, and others too. I think this is a very tough and complex topic, but one that has a big influence on how others perceive our work.

Cheers,
D.

[arith]

My names not John, got it; your not interested in my comments about different kinds of sharpening. Well there exists lots of different kinds of sharpening, and every one has its place to make a photo special.

With digital, you have to sharpen some way; in fact I think I will sell all my equipment to get a decent film medium format camera, then the main job of sharpening isn't going to happen except by chemical means, weaker solution processed longer.

A decent medium format camera even second hand costs more than the **** I've got, so I will keep sharpening. Film is not the same.

I keep saying; digital is only made to look like film, it is completely different.

[The Blue Boy]

Hi guys,

Quite suprised Colin hasn't commented. About a year and a half ago a similar thread got started (can't find it) and Colin recommended the book, Real World Image sharpening with Adobe Photoshop, by Bruce Fraser. There is a newer version of the book, but at the time (and even now) it quite simply is the industry standard for this subject. It should be required reading also for noise reduction. It tackles sharpening in three ways.

Here's the original blog post. Enjoy, or tear your hair out.

[David deSousa]

My names not John, got it; your not interested in my comments about different kinds of sharpening. Well there exists lots of different kinds of sharpening, and every one has its place to make a photo special.

With digital, you have to sharpen some way; in fact I think I will sell all my equipment to get a decent film medium format camera, then the main job of sharpening isn't going to happen except by chemical means, weaker solution processed longer.

A decent medium format camera even second hand costs more than the **** I've got, so I will keep sharpening. Film is not the same.

I keep saying; digital is only made to look like film, it is completely different.

I apologize, Steve, Arith, or whatever, I meant no slight whatsoever. I am interested in your comments, which were not for my eyes only I hope. In fact, I agree with most of what you say above. I was in part hoping someone else would chime in. I didn't intend a monologue here in the first place.

Yes, I get confused frankly with all these incomprehensible, cutesy monikers and screen names. I have never been enamored of those things. The quote in my last post was from John's post, actually, which seems to me I got right. So cool down bro, I'm not your enemy!

I am not saying one should not sharpen. I explained that. And I was intending to devote separate post to your well presented series of pictures, and I will if we are good. I don't want to irritate you any more, however.

I am an old film guy. I have been doing digital for only four years or so. From age 10 until age 66 film was photography to me. I have one 35mm film camera left over out of thousands of dollars worth of film-based equipment, all the rest, such as it is, is digital now. I own Photoshop CS5 and some plug-ins, not free I think you would agree. Why would I invest in digital if I didn't in most ways agree with what you have said? Sorry if that makes you unhappy.

David