A Road to Sharpness

[xpatUSA]

It's interesting how we rely on post-processing for image sharpness. For example, the CiC mantra of several sharpening steps from 'capture' to the final image. It's also interesting how blurry the original captured image can be, especially on a high MP camera shot with less than perfect focus or a less than perfect lens!

By way of illustration, allow me to present an image at three stages in it's life:



At center, we see what is as near as I can get to 'what the sensor captured'. The image is simply the RGB channels from my Sigma SD9 presented without conversion as an export from RawDigger. Here, it is clear that the image is not terribly sharp.

At left, we see the RAW conversion by Sigma's PhotoPro v3.5.2. Saved as ProPhoto 16 bpc TIFF. It looks a bit sharper, but not a lot. I tend to neutral settings in SPP, preferring to do the fancy stuff elsewhere.

At right, we see the miracle of post-processing in all it's glory! RL de-convolution sharpening in RawTherapee with the following settings:

DeconvRadius=0.57
DeconvAmount=75
DeconvDamping=20
DeconvIterations=47

Not presenting this as the 'best' way to sharpen - we all have our own ways for that. Mainly, the original image blur is of interest, which is rarely seen except by pixel-peepers such as myself.

[chauncey]

Aah...could you not have done as well using LR/PS CC?

[xpatUSA]

Aah...could you not have done as well using LR/PS CC?

No, I could not, William. I don't have LR, I don't have PS and I most certainly don't do CC.

The actual point was how blurry the sensor captures can be and how essential post-processing is to produce decent image acutance.

[IzzieK]

Very interesting subject, Ted. I wonder what the other expert heads will be saying???

[DanK]

No, I could not, William. I don't have LR, I don't have PS and I most certainly don't do CC.

To be fair, I am guessing that Chauncey's question could be rewritten as "couldn't one do as well using LR/PC CC?" To which the answer is presumably "yes, and also with <insert other software names here>"

However, I realize that was not the point of your post, and while I knew the general principle, I found your concrete example interesting.

BTW, this may get tomatoes thrown at me, or maybe just have me marked as an ignoramus, but I for one have no truck with the mantra of multiple sharpening steps. [Sorry, for those not from the US: I don't know how common this idiom is. Here, "have no truck with" means "don't accept at all."] In particular, I think the distinction between capture and creative sharpening is often meaningless. To take an extreme example, suppose one uses a parametric editor such as Lightroom and edits an image solely to be displayed on a computer monitor. You could follow the mantra and do modest capture sharpening at the beginning and creative sharpening later, and the LR defaults actually do apply a bit of capture sharpening when you import the image. However, if I am not mistaken, the final product is completely independent of the order in which edits are entered. In other words, if I am not wrong, you could zero out the default capture sharpening and simply sharpen once at the end and be done with it. The honest answer is that I often have done that because at some points have zeroed out LR's default capture sharpening. I have no idea which of my images were processed in which of these two ways, and I would bet real money at unfavorable odds that no one looking at the images could tell. And there is no need for further output sharpening, as the intended display medium is the same as the editing display. So, I end up with just one sharpening step before posting to the web, which I generally do at the end of LR edits or in PS if have reason to take the image into PS.

Where multiple sharpening stages becomes essential is when one prepares an image for an output medium other than the one used for editing--e.g., for printing. The one needs the first type--whatever one calls it, the sharpening that takes one from the raw image to the edited image on screen--and then additional sharpening to handle what happens when the image is printed.

Ready, aim, throw.

[Manfred M]

Carefully said, the three step sharpening that a lot of members use, probably does not apply to the Sigma, as I don't believe it needs an AA filter as it doesn't use a Bayer filter. The first step of sharpening on other cameras is merely to counteract the softening from the AA filter. I guess some of the other cameras like all of the medium format ones, the full frame Leicas and D810 cameras which don't have an AA filter either would skip this step as well.

The second step of sharpening is exactly what you have done, the so called "in-process" sharpening which gets the image looking correct at 100% magnification. It also includes any localized sharpening that a specific image may require.

The third step in sharpening is "output sharpening", where adjustments are made for the final image size that is either displayed or printed. I find that I rarely bother with output sharpening when resizing for display on the web, as when I downsize the image, I actually may have to add a touch of blur to compensate for the effects of downsizing.

[Manfred M]

Dan - as you are a Lightroom user, your assumption is correct, as I don't believe that there is any localized sharpening functionality in that software.

As a Photoshop user, I can apply localized sharpening via layers, i.e. sharpen only parts of an image, so in my case, I do "import sharpening" as I open an image, much in the same way you would in Lightroom, but in certain images, especially in headshots, I will do a bit of in-process sharpening of eye lashes, eyebrows, eyes, sometimes lip details, etc, so I would make a distinction between the two types of sharpening.

[chauncey]

"have no truck with" means "don't accept at all

Means the same thing over here...among the rural type folks.

Gotta agree with Manfred on this sharpening thingy.

[DanK]

Manfred,

Thanks. Point taken: there are more instances than the one I gave in which there are reasons to sharpen in steps.

However, I think I made my point unclearly. I understand the need (at least with my cameras, complete with AA filters) to sharpen to offset the loss of sharpness in the capture. My point was that the distinction between capture and creative sharpening really reflects a difference in the reasons sharpening is needed, not when one should sharpen. We now have on the table a couple of cases in which sharpening in stages makes sense, and I am sure there are others. However, in those cases, the reasons for doing the sharpening in stages are not necessarily related to factors that make sharpening necessary. For example:

-- in the example I gave, a single sharpening step at any point in the parametric editing process will have the same result as doing the same amount of sharpening in two separate stages. [I honestly don't recall whether I currently have LR set to do capture sharpening or not, as the total sharpening applied to the product will be the same regardless.]

--in your example of selective sharpening, there would be a reason to sharpen in separate steps even if one shot a camera with no AA filter and hence no need for 'capture sharpening.'

So, my point is that I don't find it useful to maintain the distinction between capture and creative sharpening. It's more helpful, I think, to start with the sharpening one wants (the output medium, whether selective or not, whatever) and then decide on an approach to sharpening that fits with those goals.

Dan

[NorthernFocus]

...I honestly don't recall whether I currently have LR set to do capture sharpening or not...

The LR default setting is "25" on the sharpening slider(whatever that means). I haven't found a way to turn it off in any preferences etc. So unless I'm mistaken, unless you set the slider to zero in each image, it "capture" sharpens by default.

I'm always interested reading all these technical explanations about sharpening. I'm amazed that I ever get a decent looking image because I sharpen the way anyone says you should. Until I started using LR I never did any capture sharpening. At least not consciously. I've always tried to undo any in camera setting and start as raw as possible with my images. And typically only do output sharpening.

Now that I shoot D7100 and D810 I guess capture sharpening is a moot point anyway. I frequently get comments here on CIC that images that I post from the D7100 are over sharpened. And in most cases the ONLY sharpening that they've been given is the LR export sharpening for screen set to "normal". That after deliberately turning "capture" sharpening off in LR. Though in all fairness, the clarity slider in LR is essentially a micro contrast/coarse sharpening tool. Recently I've been shying away from clarity.

[Manfred M]

Dan - again, from a Lightroom standpoint, I can see where you are coming from.

In the Photoshop world things are definitely a bit less straight forward. Generally input sharpening is done at the RAW conversion stage, and in-process sharpening will be done in Photoshop itself. While in Lightroom, you can tweak settings and go back and change things, but the Photoshop workflow is a bit different.

Once you click the "Open Object" button in Adobe Camera RAW (ACR) and start editing in Photoshop and save the file (as a *.psd; Photoshop document), you have no more ability to do any edits in ACR (or any other RAW converter). So if I do any edits that impact the sharpness; for instance additional noise reduction, I have to use Photoshop, or Photoshop plug-in, like Nik Dfine.

[Manfred M]

The LR default setting is "25" on the sharpening slider(whatever that means). I haven't found a way to turn it off in any preferences etc. So unless I'm mistaken, unless you set the slider to zero in each image, it "capture" sharpens by default.

Dan - easy to change the defaults in LR.

Set you sharpening parameters the way you want them. Then click on the "Develop" tab and select "Select Default Settings" on the drop down list and click the "Update to Current Settings" button. Until you change sets or reset to the default, your sharpen settings will carry over to any RAW file that you open and the new settings will remain, even when you shut down Lightroom.

[Stagecoach]

Once you click the "Open Object" button in Adobe Camera RAW (ACR) and start editing in Photoshop and save the file (as a *.psd; Photoshop document), you have no more ability to do any edits in ACR (or any other RAW converter). So if I do any edits that impact the sharpness; for instance additional noise reduction, I have to use Photoshop, or Photoshop plug-in, like Nik Dfine.

Manfred,

I have found that if I save the working PS file document in '.psb' format I can open that file at any time later in PS and have the ability by using the 'Camera Raw Filter' function to return back into ACR and undertake editing.

[Manfred M]

Manfred,

I have found that if I save the working PS file document in '.psb' format I can open that file at any time later in PS and have the ability by using the 'Camera Raw Filter' function to return back into ACR and undertake editing.

Thanks for the tip, Grahame.

I just checked it out. It works for *.psd files too. It's nice to have another tool in the toolkit.

[Stagecoach]

Thanks for the tip, Grahame.

I just checked it out. It works for *.psd files too. It's nice to have another tool in the toolkit.

You are welcome Manfred,

The files are 'larger' but a small price to pay if it's going to give that added ability if required.

[dje]

With CS6, when you open an image from ACR into PS, you can do it as a straight image (Open Image) or a Smart Object (Open Object). The Open button can be set to either as a default. Or if it is normally sitting at Open Image, hold the shift key down and Open Image will change to Open Object.

If the image is opened as a Smart Object, you can double click on the Smart Object layer in PS and it will re-open it in ACR for further editing. You can then return to PS for further editing. You can also do this after it has been saved as a psd or psb.

Dave

oops, I'm too late, just seen M's post.

[pnodrog]

Dan - as you are a Lightroom user, your assumption is correct, as I don't believe that there is any localized sharpening functionality in that software.

As a Photoshop user, I can apply localized sharpening via layers, i.e. sharpen only parts of an image, so in my case, I do "import sharpening" as I open an image, much in the same way you would in Lightroom, but in certain images, especially in headshots, I will do a bit of in-process sharpening of eye lashes, eyebrows, eyes, sometimes lip details, etc, so I would make a distinction between the two types of sharpening.

In lightroom you can use the adjustment brush and leave all adjustments (apart from sharpen) set to 0 and set sharpen up to 100 and you can get some localised sharpening. For portraits you can use this tool to lighten eyes, add contrast and/or saturation to them and up the sharpness slightly - fine for eye lashes but you need to do a separate adjustment on the eyebrows because generally you do not want them or the surrounding area lightened.. I must confess when I want optimum control I use Photoshop.

[dje]

Whilst I recognize the 3 stage sharpening process as legitimate, I rarely use the middle step, the so called "creative sharpening". I do capture sharpening in ACR and regard this as compensation for all softening effects in capture - AA filter, lens aberrations and diffraction, and the discrete nature of sensor pixels. If I do want to create extra sharpness to parts of an image, I do this in PS. I use output sharpening in PS after re-sizing for screen and web display (having used the non-sharpened version of bi-cubic for re-sizing.)

Each to his own !

Dave

[NorthernFocus]

Dan - easy to change the defaults in LR.

Set you sharpening parameters the way you want them. Then click on the "Develop" tab and select "Select Default Settings" on the drop down list and click the "Update to Current Settings" button. Until you change sets or reset to the default, your sharpen settings will carry over to any RAW file that you open and the new settings will remain, even when you shut down Lightroom.

Thanks for that, Manfred. It appears that you can set the defaults for each camera. When I did the above, the box that opened up indicated the defaults would be changed for "files with following attributes" which showed D7100 which was the body used to shoot the image that I had opened at that particular time. There is also a big warning that the changes can't be undone but at the same time a reset button to go back to original defaults. It's also not self evident whether it is global for specific to that particular catalog. So I'll need to do a bit more investigation before using that feature. But it will be welcome because the only files that I leave the original capture sharpening turned on is for low ISO files shot with the D4.

Also so you understand, I don't use LR exclusively. I basically use it like ACR. If the file doesn't need additional processing then I'm done. But I also use Perfect Photo Suite and in some cases PSE11. Though as PPS improves I find myself going to PSE less and less. There are some layering techniques that are still much easier in PSE. But its Achilles heal is that it is limited to 8-bit processing for all of the advanced functions. But due to my experience/comfort level with it, I still go to PSE to finalize files for printing. One reason for that is that is when I do selective sharpening if needed which the other tools still don't do as well/easily.

I've never understood PS/PSE being characterized as non-reversible editors. While technically correct, functionally all one has to do is retain intermediate layers. Granted it causes larger files, but if the work is critical enough to warrant the effort, the file size is likely the least of the evils.

[mikesan]

Carefully said, the three step sharpening that a lot of members use, probably does not apply to the Sigma, as I don't believe it needs an AA filter as it doesn't use a Bayer filter. The first step of sharpening on other cameras is merely to counteract the softening from the AA filter. I guess some of the other cameras like all of the medium format ones, the full frame Leicas and D810 cameras which don't have an AA filter either would skip this step as well.

The second step of sharpening is exactly what you have done, the so called "in-process" sharpening which gets the image looking correct at 100% magnification. It also includes any localized sharpening that a specific image may require.

The third step in sharpening is "output sharpening", where adjustments are made for the final image size that is either displayed or printed. I find that I rarely bother with output sharpening when resizing for display on the web, as when I downsize the image, I actually may have to add a touch of blur to compensate for the effects of downsizing.

I think this sums it up very well. What software one uses at the various stages is simply a matter of personal preference.