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Lenses and sharpening



 
 
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  #41  
Old September 16th 14, 03:08 AM posted to rec.photo.digital
nospam
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Posts: 24,165
Default Lenses and sharpening

In article , Eric Stevens
wrote:

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.


Fine, fine. If you wear a reversible jacket do call it, too, a
non-destructive work flow?

Of course not. There are several subtly different meanings to the word
'reversible' and you seem to have only learned one of them.


floyd would be the one who has only learned one of them.

everything in a non-destructive workflow is reversible. that's the
whole *point* and why it's so useful.
  #42  
Old September 16th 14, 03:08 AM posted to rec.photo.digital
Floyd L. Davidson
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Posts: 5,138
Default Lenses and sharpening

nospam wrote:
In article , Eric Stevens
wrote:

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.


I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.


there are indeed such functions, but that doesn't matter to users. they
want to edit photos, not learn mathematical theory.

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.


Squirm all you like, but USM is well known to be a
non-reversible function.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)
  #43  
Old September 16th 14, 03:12 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Lenses and sharpening

In article , Floyd L. Davidson
wrote:

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.


there are indeed such functions, but that doesn't matter to users. they
want to edit photos, not learn mathematical theory.

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.


Squirm all you like, but USM is well known to be a
non-reversible function.


i never said the *function* was. i said usm is reversible in a
non-destructive workflow, and it is, as are all adjustments.

that's the main point of a non-destructive workflow, something you
refuse to acknowledge.
  #45  
Old September 16th 14, 03:56 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default Lenses and sharpening

On Mon, 15 Sep 2014 22:08:25 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.


Fine, fine. If you wear a reversible jacket do call it, too, a
non-destructive work flow?

Of course not. There are several subtly different meanings to the word
'reversible' and you seem to have only learned one of them.


floyd would be the one who has only learned one of them.

everything in a non-destructive workflow is reversible. that's the
whole *point* and why it's so useful.


It's your point, but it wasn't Floyds and it's not what I want to
discuss. Why don't you shut up? You may learn something.
--

Regards,

Eric Stevens
  #46  
Old September 16th 14, 03:58 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default Lenses and sharpening

On Mon, 15 Sep 2014 22:12:53 -0400, nospam
wrote:

In article , Floyd L. Davidson
wrote:

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

there are indeed such functions, but that doesn't matter to users. they
want to edit photos, not learn mathematical theory.

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.


Squirm all you like, but USM is well known to be a
non-reversible function.


i never said the *function* was. i said usm is reversible in a
non-destructive workflow, and it is, as are all adjustments.


Yes, you changed the subject, and now you are trying to blame Floyd
for wanting to go on talking about his original subject.

that's the main point of a non-destructive workflow, something you
refuse to acknowledge.


He doesn't acknowledge it because that's not what he was (trying) to
talk about.
--

Regards,

Eric Stevens
  #48  
Old September 16th 14, 04:19 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Lenses and sharpening

In article , Eric Stevens
wrote:

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.

Fine, fine. If you wear a reversible jacket do call it, too, a
non-destructive work flow?

Of course not. There are several subtly different meanings to the word
'reversible' and you seem to have only learned one of them.


floyd would be the one who has only learned one of them.

everything in a non-destructive workflow is reversible. that's the
whole *point* and why it's so useful.


It's your point, but it wasn't Floyds and it's not what I want to
discuss. Why don't you shut up? You may learn something.


tell that to floyd.

he knows nothing about non-destructive workflows or how they work,
going so far to say that they are for cartoon characters.

if anyone needs to learn something, it's him.
  #49  
Old September 16th 14, 05:37 AM posted to rec.photo.digital
John McWilliams
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Posts: 6,945
Default Lenses and sharpening

On 9/15/14 PDT, 7:07 PM, Floyd L. Davidson wrote:
Savageduck wrote:


I got what Floyd was talking about when he was talking
of high pass sharpening, and reversing it by applying
the corresponding reverse parameter blur. However, he
also stated above, "UnSharpMask is not reversible". My
point addressed the fact that for some of us, that is
not an entirely valid statement.


That is in fact a valid statement. The USM function is
not reversible.

That isn't a opinion, it's a fact.


For one definition of the word!

  #50  
Old September 16th 14, 05:39 AM posted to rec.photo.digital
Kevin McMurtrie[_3_]
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Posts: 108
Default Lenses and sharpening

In article ,
(Floyd L. Davidson) wrote:

Kevin McMurtrie wrote:
In article ,
Alfred Molon wrote:

In article 2014091316132932858-savageduck1@REMOVESPAMmecom, Savageduck
says...
...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.


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?


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.


Mathematically, it's nothing more than a frequency enhancement. It's
like an audio EQ but for two dimensions instead of one. Maybe you're
thinking of reversing USM from a saved file that suffers from clipping
and severe loss of precision.



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.


--
I will not see posts from astraweb, theremailer, dizum, or google
because they host Usenet flooders.
 




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