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

[arith]

That is alright, I am happy

[Shadowman]

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.

David,

In question#3, I wonder if you would change your answer depending on your audience? If you thought the viewer wouldn't notice would you bother or if you thought they would notice would you decline to do so or limit it hoping they wouldn't notice? There must have been times when you showed someone an image and based on their comments you applied additional sharpening.

[Nuno]

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?

Hello to all.

I am a newby here, but as a "sharpener", I found this discussion very interesting.
I think the items that Shadowman pointed are very important but I would like to add another idea:

1 - Do you need to highlight the main subject in the picture?
2 - Are there important details that should be brought up?
3 - Does shappening creates noise? And can that noise be corrected without noticing? (ex.: Big and clean skies)

The eternal quest for more and more detail sometimes can ruin our photographs, because it can also divert the attention of the main subject in the picture. In a panning picture, we can never expect for much shapness, except for the main subject.
in pictures with a small DOF, sharpness can be a meaning of lots of noise.
I am using an overlay of "Highpass" layers to create more detail, (I use allways masks).

My basic idea here is: it is very hard to resist to apply sharpness, but it should be used only to highlight the main subject in the picture.

Thanks, Nuno.

[Jack Hogan]

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.

I have it and I don't like it: lots of pages but nothing you could not pick up off a couple of free articles and tutorials on the net. You can find the premise of the book here.

[Jack Hogan]

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?

Hello David,

Interesting topic. IMHO the answer to your question depends on your objective.

If your objective is capture sharpening, the image is clearly oversharpened. If your objective is creative sharpening, I would be interested to know what you were trying to accomplish. If you were going for an old school 'photographic' look, I think it is oversharpenened as well (as evidenced by the halos at the interface between dark ridge and blue sky - top right - for instance). On the other hand, if you were going for a post-modernist realistic look it may be just fine.

To clarify, in my mind Capture sharpening is mostly global and not subjective or scene dependent: it is what is necessary to counteract known blurring introduced by the lens and camera during the capture process, as you say. If you always shot with the same set of lens and parameters you would always apply the exact same sharpening recipe to get the most accurate representation possible of the original scene. Starting from raw, I capture sharpen all my images.

Creative sharpening instead is mostly local, subjective and scene dependent - part of the artistic process. You are 'painting' to make the image look the way you like it - enphasizing this or de-enphasizing that. By definition it is not too much or too little, as long as the effect is what you want. I often add some sort of creative sharpening to some part of my images.

[Shadowman]

Hello to all.

I am a newby here, but as a "sharpener", I found this discussion very interesting.
I think the items that Shadowman pointed are very important but I would like to add another idea:

1 - Do you need to highlight the main subject in the picture?
2 - Are there important details that should be brought up?
3 - Does shappening creates noise? And can that noise be corrected without noticing? (ex.: Big and clean skies)

The eternal quest for more and more detail sometimes can ruin our photographs, because it can also divert the attention of the main subject in the picture. In a panning picture, we can never expect for much shapness, except for the main subject.
in pictures with a small DOF, sharpness can be a meaning of lots of noise.
I am using an overlay of "Highpass" layers to create more detail, (I use allways masks).

My basic idea here is: it is very hard to resist to apply sharpness, but it should be used only to highlight the main subject in the picture.

Thanks, Nuno.

1. Do you need to highlight the main subject? Yes, but only if you have not done so with the elements (composition, contrast, filling the frame) of a good photograph and then only if you feel the need to direct the viewer to the main subject. And when you say highlight, I am assuming you mean through sharpening.

[CypherOz]

I'm new to CiC but not photography...

1. Digital images need some sharpening - its a fact of life due to the gap between pixels and the bayer pattern of GRGB

2. Masking and selective NR on the non subject and sharpening of the main subject is a common approach, esp with birds and wildlife

3. Personally I tend to use high pass sharpening (Dave's actions from here http://www.atncentral.com/sharpeners.htm )

4. Sharpening cannot fix blurry images. So here are some tips...

1. Nail your focus, for people and wildlife that means the eye (also get to eye level when you can, esp. children)
2. Get as close as you can to your subject so you don't have to crop too much (i.e. get the framing right in camera)
3. Keep your shutter speed high enough to avoid camera shake and/or subject movement
4. A noisy sharp image is better than a blurry less noisy image, raise your ISO as need to get the shutter speed you need
5. Work with your lens sweet spot as best you can

[Nuno]

1. Do you need to highlight the main subject? Yes, but only if you have not done so with the elements (composition, contrast, filling the frame) of a good photograph and then only if you feel the need to direct the viewer to the main subject. And when you say highlight, I am assuming you mean through sharpening.

I agree with you.
Of course I'm talking about photographs with good composition, ilumination and contrast.
But I allways use lots and lots of sharpening to enhance a portrait of an elderly person. But I don't use it in an photo of a little baby's face. (Sometimes I even blur it). What I am saying is, sometimes sharpening can be distractive and adds nothing to the picture.
In an out-of-focus image, I assume that something failed during the shot, or it is intentional, and in this case, I don't sharpen the image.

Hey, please don´t get me wrong. I use HighPass, Topaz and NIK sharpeners all the time!

[Gingerbaker]

What does "over-sharpened" mean?

I came back from Lasik surgery a few years ago, and for a while ( my eyes have slipped badly since) I was seeing better than 20/20. Do you want to know what the world looked like? Exactly like high-acuity photographs that commonly get attacked as "over-sharpened"!

As long as artifacts are not generated, what is judged as "sharp" is going to change, I believe - you heard it here first - over the next few years. As lenses continue to improve, and as more people get true HD programming on HDTV's, higher visual acuity than what we accept as normal right now is going to be expected.

I recently watched "King Kong" in Blu-Ray on a relatives HDTV. The resolution was stunning and equivalent to the eyesight I enjoyed in the real world during my days home right after that Lasik surgery. When that kind of acuity becomes the norm, people will expect it in their still photography as well.

[Davey]

Perhaps this is a bit late in the discussion to mention but you touch on never seeing an image in a gallery or print being "too sharp". I'm sure you know but it is easy to forget about the world of differences there to what we see on screen. I do fair amount of stuff that looks way too sharp on screen especially at 100% but the intended output is printed brochures and flyers etc. I have to print draft copies for review since people take one look on screen and mention images and artwork looks too sharp, it's always fine when comes back from printers unless I make it just right on screen when it comes back unintentionally soft.

We all know that monitors have square pixels and print is either dots for inkjet and some digital printers (ie laser) or a more varied pattern of colour in the case of offset printing and high end digital prints from pro digital press which have offset like result such as Indigos and the like. Most photos people view in print are going to be printed on inkjets or digital press if sent out for printing (some exceptions as some photoprint companies will use inkjet for certain sizes) but I mention offset too since that's what bulk stuff will usually always be.

Either way whether it be digital printing (as in laser), offset, or inkjet the nature of the print process means that the result is much softer compared to how it displays on screen. Ignoring the fact without backlighting it can appear very different the very nature of image being comprised of lots of tiny squares means it will look oversharp on monitors.

Even TVs which are identical to monitors in most respect except oval shaped pixels will render images undersharp so that's a consideration if it is for none monitor style screen viewing. The result is it takes a completely different type of sharpening approach depending on the desired viewing output and print and monitor can't really be compared as they are very different. I could be completely wrong and admit this is just my opinion and I'm far from an expert but I feel the only way to get right amount of sharpening is by having one master image and applying different levels/types for different outputs and viewing sizes. There is never going to be one correct level since medium and size/viewing distance variables change the "how much is right" by a huge amount. Again I could be wrong on this but it's what I personally have found so far.

[Nomadr]

i will just add my two penneth, i shoot mainly in raw and process through CS3, in ACR i have sharpening switched off (use 25 sharpening in preview only just so i can see if the image is ok with no camera shake),
i will always sharpen as the last stage,i only use selective sharpening through masks which gives me total control,as previously mentioned its especially important in bird photos,
if you can see halo's and other sharpening artifacts then its over sharpened,cheers martyn

[tameigh]

Thanks for the great tips. I had no idea that sharpening was required on most digital images. I just improved one I had been working on. I was getting discouraged that all of my pictures had a Vaseline haze. Bought a new tripod, which improved things, but still I don't get results like I see here.

[Colin Southern]

Thanks for the great tips. I had no idea that sharpening was required on most digital images. I just improved one I had been working on. I was getting discouraged that all of my pictures had a Vaseline haze. Bought a new tripod, which improved things, but still I don't get results like I see here.

Hi Tim,

If you're shooting RAW then sharpening is required on ALL images. If you're shooting JPEG then some sharpening is usually applied at the time, but it's rarely an optimal amount.

Optimal sharpening of a RAW image usually requires at least 3 passes (sometimes more): Capture sharpening to counter the softening of the anti-aliasing filter, digitization process, and demosaicing, content/creative sharpening to give your images the required degree of crispness & "pop" when viewed at normal size, and output sharpening to cater for the characteristics of the printer or monitor you're using (especially after down-sampling).

I've written a bit more about it here if this helps.

[tameigh]

Thanks. Since the camera and camera raw fell in my lap, there is a lot I didn't know. I am learning though. I am enjoying working with sharpening.

[tameigh]

The real problem, I believe, was that I was re-sampling every time I cropped without knowing it. I cleared the crop settings on the tool, and this prevents the re-sampling. Then, if I need to change the size or resolution, I do it only once, knowingly, and with control of the algorithm used.

This has improved the clarity of my photos.

[tameigh]

Is this oversharpened?

It feels like it to me, but I couldn't say why.

[Nuno]

Like I see it in my monitor, it is NOT oversharpened. I like it.
The background doesn't need any sharpening, I think i can go softer. (Maybe a little blur in PS)

[Colin Southern]

Is this oversharpened?

It feels like it to me, but I couldn't say why.

Yes it is, slightly. You're starting to get high-frequency frosting on the bark of the foreground tree, and on the bird. If you wanted to fix it in this image (at this resolution) then add a low-pixel blur and then re-sharpen at a higher radius / lower amount.

For an image like this, I think that fairly standard settings should work well, so what I'd start with is ...

1. On the full resolution image, capture sharpening of 0.3 pixel @ 300% @ 0 threshold

2. On the full resolution image, content / creative sharpening of 4 pixel @ 40% @ 0 threshold

3. On the down-sampled image, output sharpening of 0.3% @ 100% @ 0 threshold - assuming that you downsampled using bicubic SMOOTHER.

Hope this helps

[jiro]

Tim, I don't know if this is relevant. Normally, over-sharpened images tend to fall on the 'overly bright and high-contrast images'. They usually go the same. Sharpen a dark image and not all can notice it unless you really magnify the image. However, sharpen a really high contrast image and you'll get that over-sharpened look. If you back down on the highlight values by playing on any software that you have that can do that, you'll find a balance between the right amount of sharpening and the right amount of brightness and contrast. On your set of 2 examples, they do look "over-sharpened" because they are bright and with high-contrast. Our eyes are a very extra-ordinary kind of machine. If you feel that it is over-sharpened yourself (in your honest to goodness assessment) then it is actually over-sharpened. We are merely agreeing with it. I hope I did not offend you on my comment.

I've included this image (edited) to explain my point:


There was no sharpening adjustment done, just some highlight values, exposure, and contrast adjustment. It looks different, doesn't it?

[Colin Southern]

In contrast, here's a quick rework where I've applied a slight blur and then re-sampled with new parameters (also a tiny tweak to cure the slight over-exposure).