Skip to main content
news

Re: Lenses and sharpening

Floyd L. Davidson
SubjectRe: Lenses and sharpening
FromFloyd L. Davidson
Date09/15/2014 07:31 (09/14/2014 21:31)
Message-ID<87bnqh1mby.fld@barrow.com>
Client
Newsgroupsrec.photo.digital
FollowsKevin McMurtrie
Followupsnospam (27m) > Floyd L. Davidson
Kevin McMurtrie (23h & 7m)

Kevin McMurtrie <mcmurtrie@pixelmemory.us>wrote:

Kevin McMurtrie
In article <MPG.2e7f6291cf0026d798cc0c@news.supernews.com>, Alfred Molon <alfred_molon@yahoo.com>wrote:

Alfred Molon
In article <2014091316132932858-savageduck1@REMOVESPAMmecom>, Savageduck says...

Savageduck
...and what PP software, & what sharpening methods do you use? I am not going to advocate one application, or method over the other, I know what advice I can give with what I am familiar with in my workflow.

Alfred Molon
Isn't unsharp mask the same across all PP applications? I would have thought it's an algorithm which is implemented in various PP applications, or are there differences?

Kevin McMurtrie
The digital form of unsharp mask is the inverse of a blur. There's both a frequency (diameter) and an intensity.

Not the case. It is the high pass sharpen tool that is the inverse of blur. They can use the exact same algorithm with different parameters. Using one and then the other virtually reverses the results.

UnSharpMask is not reversible.

The fancier sharpening tools analyze an image and adapt the sharpening to different types of blur in the image. This handles minor focus problems, simple motion blur, and some of the radial blurring found in cheap lenses.

The super-fancy tools will trace camera shake and estimate a corrected image.

-- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) floyd@apaflo.com