Sharpening

I don't get it.

I shoot RAW
I get into Photoshop having applied some sensible sharpening in conversion
Manipulate levels etc.
Save as PSD
Then for web use
Convert to profile
Resize
And then apply unsharp mask
Usually you need some and a little fiddling about gets it OK
I have two lenses that just don't seem to like this and you get artefacts quite quickly with even modest sharpening

I don't understand how this can be as I thought the need to sharpen came from the resizing vagaries not the lens itself.

Help?

Mike

Hi Mike -

You are effectively sharpening twice - once when you "applied some sensible sharpening in conversion" and once when applying the unsharp mask after re-sizing etc. I'm sure that others will have other ideas, but applying the unsharp mask is the very last thing I do to a photo. I leave the sharpening options well alone in Lightroom and just do it in PS4 if necessary.

Resizing & heavy postprocessing can create a need for further sharpening Mike, but a RAW image will need sharpening anyway, even with the best lenses. I believe this is to do with the filter in front of the camera sensor causing a little loss of sharpness.

A technique I've read about but haven't practiced as much as I should (cos I'm lazy) is "Lab colour sharpening" where basically you only sharpen the "lightness" channel whilst leaving the colour layers intact. Sharpening can be pushed much further this way.

I have a tendency to oversharpen anyway, so should really look into this & maybe create a PS custom function for it to cut down on processing time.

Mike

As I understand it a raw file needs some "capture sharpening" at the raw conversion stage.

After resizing you are right to use the USM to do "output sharpening".

My question is what size are you viewing the final image at when you apply USM ? Only 100% view makes sense.

As far as I know all RAW conversions require sharpening due to the technology and I tend to accept the PS defaults except when using my lensbaby and sometimes if I use a lens wide open. I'll happily be corrected but I think RR is agreeing with me that you need to apply sharpening at the RAW stage but I don't think this is the same as the unsharp mask in any case.

So I'm pretty certain I am applying RAW conversion sharpening correctly.

As I say what I don't get is why the Vivitar macro (a cheap but good lens) usually requires almost no sharpening after resizing. The same is true of the 70 ltd but not the 21 ltd for example.

I can see that some PP might introduce the need for the unsharp mask while other PP might encourage the production of artefacts. I suppose there's no easy answer and I'll be trawling the internet for some time

Mike

Maybe the answer is in how sharpening works since it creates the appearance of sharpness by increasing contrast with edges.

So we have two bases now, edges is depend on resolution and we have contrast.
Resolution is depending on how well the lens keep all the colours/light together basicly.
Contrast is also a lens quality so there you have it why things are different per lens.

Maybe not the best explanation or 100% correct but I believe it comes close to the answer you're seeking.

Sharpening is a minefield of information, but good advice is found in Martin Evening's books.

Many people turn off the sharpening in the RAW converter and as a general principle (keeping things very simple) sharpening is done as the very last stage in Photoshop. Different sizes of print and different useages such as Web need different amount of shapening. As do different resolutions of sensor.

Assumning 10 MP or more, try simple Unsharp mask, Radius 1.9, Threshold 3, and using the following as starting points. Web use at 1000 pixels wide, 50% Print at 300ppi at A3 100%

The Lab method works but is getting a bit unnecessary now. There are also High Pass techniques and Blending Mode techniques. Then of course our very own Mattmatic's "Sharpen-o-Matic" just to name a few.

Finally, +1 in camera to sharpening can help as well.

If submitting to fotoLibra, do not sharpen at all in Photoshop. Sharpening in-camera is allowed.

John the +1 in camera doesn't work if you shoot RAW but is the best way to do it if you shoot JPG though.

It will work if you use Pentax Digital Camera Utility. The info is embedded in the image and used by Pentax Raw Converter.

I've heard it also works with the lens correction of the K7.
But you must agree that the program does that to the RAW file on the computer so you can just as easily do that manually on your PC with the same effect.
Now with JPG you want to have the perfect photo straight out of the camera since every time you re-save it you lose data because of the compression.

LAB mode works for me, create an action and one key press and sorted.

Hi Mike,

Just to add my 2 cents to this.

As above mentioned I dont do any sharpening in the RAW conversion and leave it all until I have finished what ever processing/editing I am doing.
Then I use the default sharpening in PS (Filters>Sharpen>Sharpen) that usually suffices. If I feel I need more then I will create a duplicate layer and use the High pass filter (Filters>Other>High pass) and adjust the radius to suit. Then I set the blending mode of this new layer to either Overlay, Soft Light or Hard Light and finally I reduce the opacity of the new layer until it looks right.

Regards
PaulM

There is an excellent guide on TheLightsRightStudio.com
http://www.thelightsrightstudio.com/digital-darkroom.htm

Check out "Put a fine edge on your sharpening skills" on this page: http://www.thelightsrightstudio.com/tutorials-pdf.htm


Matt