Sharpening

[David Sutton]

Human vision is dominated by medium to low frequency detail, so enhancing pixel level detail at the expense of low to medium frequency detail may be a less than optimal sharpening strategy. This video explains some things pretty well: https://www.youtube.com/watch?v=iBKDjLeNlsQ&ab_channel=FallenEmpireDPS

Best regards
Erik

Eric, thanks for that link. It's that first time I've got an idea of what mtf graphs are about and their limits. I tend to sharpen mid tones and highlights more than shadows by using a luminance mask, but depending on the output and viewing distance I wonder now if I should look at pushing low and medium frequency detail a bit more.

I got up this morning and had a bet with myself that OP's thread had turned into a discussion on optimal sharpening. Well I guess it's interesting. Perhaps a new thread could be started.

[Bart_van_der_Wolf]

Call it what you will but obsession (or otherwise) to understand and make improvements is what makes the world go round and advance.

Hi Tony,

I somewhat agree, as my signature quote suggests, although I've also suggested and agreed with the gist of Mark's point in that there has to be a visual and/or workflow benefit to be had, otherwise it really becomes an obsession.

And that's part of the difficulty in getting the message across. There are many possible applications for photographic images, some for small size web-publishing (for which our cameras usually have way too much resolution), and some for (very) large output which demands the ultimate in technique, and meticulous attention for detail (since errors accumulate and are literally magnified).

Those that are prepared to work (and capable of understanding the fine details!),  freely share their findings and are open to discussion deserve our admiration or at least our attention.

When I started working commercially in Photography, almost 4 decades ago with Kodak (in the Netherlands) as an 'Instrumentation/Photofabrication/Aerial/Scientific' products customer support representative, I had to share lots of in-depth technical and practical usage information, and found that sharing information also caused others to share their information. The resulting synergy benefited all involved. I am still a strong believer in synergy, 1+1>2. Also an undogmatic attitude, and willingness to embrace new insights has proved to be beneficial.

BTW, is your server down as I was trying to access your article on image quality and sharpening (the one where the user inputs requirements)?

Yes, sorry, I'm in the middle of an ISP transition that's not going as smooth as I had hoped, and a lot of work that keeps me from fixing things. If there are any specific things needed, just drop me a PM and I'll see what I can do.

Cheers,
Bart

[Mark D Segal]

............... Perhaps a new thread could be started.

Sure, and it will be interesting to see the value-added relative to the other 766 entries in this Forum accumulated since 2010 that respond to the Search Term "Sharpening" - of course there is never an end to what one could learn - things keep evolving.........

:-)

OK - no joking - no harm! But on a more serious note, I do think it important to keep tools and purpose well-related to each other in whatever further discussion one wishes to have on this topic.

[TonyW]

...Yes, sorry, I'm in the middle of an ISP transition that's not going as smooth as I had hoped, and a lot of work that keeps me from fixing things. If there are any specific things needed, just drop me a PM and I'll see what I can do...

Hi Bart, what a kind offer many thanks. 
Its just that I had saved some of your works as bookmarks for later study and recently replaced an old and faulty PC found that I had neglected to back up this aspect so when I rediscovered them you had seemingly gone awol  .  Anyway hope your ISP transition improves

OK - no joking - no harm! But on a more serious note, I do think it important to keep tools and purpose well-related to each other in whatever further discussion one wishes to have on this topic.

I know there are a lot of topics and opinions on sharpening here and elsewhere on the net, some plain wrong, some old but still relevant and some either not seen by me (or others) or quite new based on different tools.

I do agree with yours and Bart's points that there has to be a visual and/or workflow benefit to be had to make jumping through sharpening hoops worthwhile.  And I still cannot work out just how many angels can dance on the head of a pin