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Chromat Aberration Correction???

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Anonymous
March 30, 2005 9:16:57 PM

Archived from groups: rec.photo.digital (More info?)

I downloaded a trial version of JSC Paint Shop Pro 9.
It includes a tool for CA. I was expecting a routine
to realign the various colors but it appears instead to
merely be some sort of color filter.

Are all CA tools just color touchups, or do some of them
actually realign the various colors' images?

--
Chuck Forsberg caf@omen.com www.omen.com 503-614-0430
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Technology Inc "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231 FAX 629-0665
Anonymous
March 30, 2005 10:04:56 PM

Archived from groups: rec.photo.digital (More info?)

Chuck Forsberg wrote:
>
> I downloaded a trial version of JSC Paint Shop Pro 9.
> It includes a tool for CA. I was expecting a routine
> to realign the various colors but it appears instead to
> merely be some sort of color filter.
>
> Are all CA tools just color touchups, or do some of them
> actually realign the various colors' images?

how do you imagine that the perfectly aligned color images,
coming out of the camera perfectly aligned,

would get misaligned?

>
> --
> Chuck Forsberg caf@omen.com www.omen.com 503-614-0430
> Developer of Industrial ZMODEM(Tm) for Embedded Applications
> Omen Technology Inc "The High Reliability Software"
> 10255 NW Old Cornelius Pass Portland OR 97231 FAX 629-0665
March 31, 2005 11:25:27 AM

Archived from groups: rec.photo.digital (More info?)

Chuck Forsberg wrote:

> I downloaded a trial version of JSC Paint Shop Pro 9.
> It includes a tool for CA. I was expecting a routine
> to realign the various colors but it appears instead to
> merely be some sort of color filter.
>
> Are all CA tools just color touchups, or do some of them
> actually realign the various colors' images?


I think the photoshop raw plugin actually re-aligns the different color
channels. There are a couple sliders & you can see the magenta/green,
etc move from one side to the other while adjusting then stop when it's
best centered. The other technique I've seen uses Panotools to re-scale
the different color channels. That one sounds like a lot of work.
Related resources
March 31, 2005 12:51:34 PM

Archived from groups: rec.photo.digital (More info?)

I got the same kind of issue when photographing the moon afocally
thorough my 150mm reflector with an Oly C-5060; I got noticable
red-green fringing. It varied depending on which eyepiece I used, I
have a couple of Plossls and a wide-field - they were quite different.
A reflector (Newtonian) telescope doesn't have any CA issues from the
mirror, so it was either the eyepieces or the camera, and I've never
had issues with the camera before. Spotting scopes don't have the
complicated array of lenses that more expensive refractor telescopes
use to prevent CA - they're meant more for daytime use, so CA isn't as
much of an issue if it occurs.

I simply changed the pic to grey-scale - it got rid of the fringes
quite nicely, while the color of the moon didn't change at all. Here's
the grey-scale pic, sorry but I don't have the original with the
fringing available to display right now:

http://img.photobucket.com/albums/v496/ecmcdougall/Seao...

You could try "selecting" the CA by hand and then desaturating it a
bit; that's pretty much what most of the plugins do, though.

Good Luck!
ECM
Anonymous
March 31, 2005 4:18:54 PM

Archived from groups: rec.photo.digital (More info?)

Chuck Forsberg wrote:
> I downloaded a trial version of JSC Paint Shop Pro 9.
> It includes a tool for CA. I was expecting a routine
> to realign the various colors but it appears instead to
> merely be some sort of color filter.
>
> Are all CA tools just color touchups, or do some of them
> actually realign the various colors' images?
>
Unfortunately how a lens handles light of different wave lengths is why
you get chromatic abberations in the first place. Digital sensors also
contribute to the problem. The colours are not "misaligned" in the first
place, just focused at different lengths and the unfocused 'colour' is
fuzzy and looks larger than the focused colours or it's focused in
different place.

CA can only be corrected after shooting by manipulating the colour which
is causing the fringe in the edge which is offensive. Many programs are
out there to 'fix' CA but all they do is identify the colour abnormality
of edges and remove the offending colour.

Sadly, this often results in an identical colour elsewhere in the image
also being killed. Another point worth considering is that a lot of
'colour fringing' caused by sensors recording against lighter
backgrounds can be mistaken for CA. These purple and sometimes magenta
fringes are much easier to correct with software than true abberations
from a lens.

The 'filters' you can get for Photoshop and others only delete the
colour which offends on the most noticible edge is is on. THat's about
as good as it gets unless your wallet is large for expensive glass and
even then, you can still get CA if you don't know how it occurs and how
to avoid it.

Douglas.
Anonymous
March 31, 2005 4:18:55 PM

Archived from groups: rec.photo.digital (More info?)

In article <424b5e11$1@dnews.tpgi.com.au>,
Graham Hunt <million_pics@yahoo.com> wrote:

> The 'filters' you can get for Photoshop and others only delete the
> colour which offends on the most noticible edge is is on.


Can you elaborate on these filters and how they might be obtained?

Here is an example of what I am trying to eliminate. Note the purple
fringe:

http://www.mhmyers.com/temp/fringe.jpg

m-m
March 31, 2005 4:18:56 PM

Archived from groups: rec.photo.digital (More info?)

"M-M" <nospam@ny.more> wrote in message news:nospam-
> Can you elaborate on these filters and how they might be obtained?
>
> Here is an example of what I am trying to eliminate. Note the purple
> fringe:
>
> http://www.mhmyers.com/temp/fringe.jpg
>
> m-m

That fringe is not chromatic abberation, it's sensor based and is a classic
example of the problems associated with Sony and Kodak sensors when there
are bright (or dull) objects against a dark (or bright) background. Other
sensors will also produce the effect but those two are the worst I've
experienced. Add it to a cheap lens and it doesn't get much worse than that!

You should get a program called CAfree from www.Shaystephens.com It costs
$10 US and is well worth the cost. Unfortunately it need photoshop or
paintshop pro to work but it does indeed work. I found Shay to be on the
ball and easy to communicate with and no... I have no relationship in any
way, shape or form other than to have bought his product to fix one of my
wife's Olympus camera's fringed pictures so I could enlarge it... But that's
another story.

Douglas
Anonymous
March 31, 2005 5:27:19 PM

Archived from groups: rec.photo.digital (More info?)

Kibo informs me that Crownfield <Crownfield@cox.net> stated that:

>Chuck Forsberg wrote:
>>
>> I downloaded a trial version of JSC Paint Shop Pro 9.
>> It includes a tool for CA. I was expecting a routine
>> to realign the various colors but it appears instead to
>> merely be some sort of color filter.
>>
>> Are all CA tools just color touchups, or do some of them
>> actually realign the various colors' images?
>
>how do you imagine that the perfectly aligned color images,
>coming out of the camera perfectly aligned,

If they were perfectly aligned, there wouldn't be any chromatic
aberration, surely?

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
Anonymous
March 31, 2005 5:27:20 PM

Archived from groups: rec.photo.digital (More info?)

Lionel wrote:
>
> Kibo informs me that Crownfield <Crownfield@cox.net> stated that:
>
> >Chuck Forsberg wrote:
> >>
> >> I downloaded a trial version of JSC Paint Shop Pro 9.
> >> It includes a tool for CA. I was expecting a routine
> >> to realign the various colors but it appears instead to
> >> merely be some sort of color filter.
> >>
> >> Are all CA tools just color touchups, or do some of them
> >> actually realign the various colors' images?
> >
> >how do you imagine that the perfectly aligned color images,
> >coming out of the camera perfectly aligned,
>
> If they were perfectly aligned, there wouldn't be any chromatic
> aberration, surely?

and I think you would be incorrect.
the image colors are correctly aligned,
in the center parts of the image,
but probably towards the edge, the color alignment varies
as a function both the color and the distance from center.

're-alignment', better called 'correction'
would be a function of the lens, of the sensor, of the color,
and of the position from the center of the image.

someone already makes such a correction tool.
it also corrects lens distortion.
you buy the correction software in modules
for the camera, and for each lens separately.


> --
> W
> . | ,. w , "Some people are alive only because
> \|/ \|/ it is illegal to kill them." Perna condita delenda est
> ---^----^---------------------------------------------------------------
Anonymous
March 31, 2005 7:55:58 PM

Archived from groups: rec.photo.digital (More info?)

In article <8jP2e.18737$C7.12876@news-server.bigpond.net.au>,
"Douglas" <decipleofeos@hotmail.com> wrote:

> > http://www.mhmyers.com/temp/fringe.jpg
> >
> > m-m
>
> That fringe is not chromatic abberation, it's sensor based and is a classic
> example of the problems associated with Sony and Kodak sensors when there
> are bright (or dull) objects against a dark (or bright) background. Other
> sensors will also produce the effect but those two are the worst I've
> experienced. Add it to a cheap lens and it doesn't get much worse than that!

It's likely more from the lens (it's a spotting scope). It happens if I
connect a film camera to it and I can even see it just visually without
a camera connected.

m-m
Anonymous
March 31, 2005 9:30:56 PM

Archived from groups: rec.photo.digital (More info?)

"Chuck Forsberg" <caf@omen.com> wrote in message
news:iIGdnSy5Fs4U0tbfRVn-vw@giganews.com...
>I downloaded a trial version of JSC Paint Shop Pro 9.
> It includes a tool for CA. I was expecting a routine
> to realign the various colors but it appears instead to
> merely be some sort of color filter.
>
> Are all CA tools just color touchups, or do some of them
> actually realign the various colors' images?
SNIP

No, some really correct for the geometric distortion which can differ
per color channel.
http://www.uni-koeln.de/%7Eal001/radcor.html will do what you are
looking for.

Bart
Anonymous
April 1, 2005 8:34:49 AM

Archived from groups: rec.photo.digital (More info?)

In message <8jP2e.18737$C7.12876@news-server.bigpond.net.au>,
"Douglas" <decipleofeos@hotmail.com> wrote:

>"M-M" <nospam@ny.more> wrote in message news:nospam-
>> Can you elaborate on these filters and how they might be obtained?
>>
>> Here is an example of what I am trying to eliminate. Note the purple
>> fringe:
>>
>> http://www.mhmyers.com/temp/fringe.jpg
>>
>> m-m
>
>That fringe is not chromatic abberation, it's sensor based and is a classic
>example of the problems associated with Sony and Kodak sensors when there
>are bright (or dull) objects against a dark (or bright) background.

Nope. Look closely; there are purple *AND* green casts, if you zoom in,
and they are directional.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
April 1, 2005 8:34:50 AM

Archived from groups: rec.photo.digital (More info?)

JPS@no.komm wrote:
> "Douglas" <decipleofeos@hotmail.com> wrote:
>>"M-M" <nospam@ny.more> wrote in message news:nospam-
>>>
>>>Here is an example of what I am trying to eliminate. Note the purple
>>>fringe:
>>>
>>>http://www.mhmyers.com/temp/fringe.jpg
>>
>>That fringe is not chromatic abberation, it's sensor based and is a classic
>>example of the problems associated with Sony and Kodak sensors when there
>>are bright (or dull) objects against a dark (or bright) background.
>
>
> Nope. Look closely; there are purple *AND* green casts, if you zoom in,
> and they are directional.


That's really strong though. I wonder if it was cropped and was off to
the side. Did the OP say this was through a telescope with maybe pretty
iffy optics?
Anonymous
April 2, 2005 1:49:16 AM

Archived from groups: rec.photo.digital (More info?)

In article <RJKdnY3gzOIXStHfRVn-qg@speakeasy.net>, paul <paul@not.net>
wrote:

> >>>http://www.mhmyers.com/temp/fringe.jpg
> >>
> >>That fringe is not chromatic abberation, it's sensor based and is a classic
> >>example of the problems associated with Sony and Kodak sensors when there
> >>are bright (or dull) objects against a dark (or bright) background.
> >
> >
> > Nope. Look closely; there are purple *AND* green casts, if you zoom in,
> > and they are directional.
>
>
> That's really strong though. I wonder if it was cropped and was off to
> the side. Did the OP say this was through a telescope with maybe pretty
> iffy optics?

OP here.

Yes, a telescope- really a zoom spotting scope with about 30 internal
lenses.

m-m
April 2, 2005 1:49:17 AM

Archived from groups: rec.photo.digital (More info?)

M-M wrote:

> In article <RJKdnY3gzOIXStHfRVn-qg@speakeasy.net>, paul <paul@not.net>
> wrote:
>
>
>>>>>http://www.mhmyers.com/temp/fringe.jpg
>>>>
>>>>That fringe is not chromatic abberation, it's sensor based and is a classic
>>>>example of the problems associated with Sony and Kodak sensors when there
>>>>are bright (or dull) objects against a dark (or bright) background.
>>>
>>>
>>>Nope. Look closely; there are purple *AND* green casts, if you zoom in,
>>>and they are directional.
>>
>>
>>That's really strong though. I wonder if it was cropped and was off to
>>the side. Did the OP say this was through a telescope with maybe pretty
>>iffy optics?
>
>
> OP here.
>
> Yes, a telescope- really a zoom spotting scope with about 30 internal
> lenses.


Well then I guess it ought to be correctable. Panotools would be a free
option, maybe tricky though.
Anonymous
April 2, 2005 5:19:32 AM

Archived from groups: rec.photo.digital (More info?)

In article <HMqdneCQLIKhc9DfRVn-hQ@speakeasy.net>, paul <paul@not.net>
wrote:

> > Yes, a telescope- really a zoom spotting scope with about 30 internal
> > lenses.
>
>
> Well then I guess it ought to be correctable. Panotools would be a free
> option, maybe tricky though.

I am having some good results with Photoshop Elements-> Enhance-> Adjust
Color-> Replace Color. I can click on the purple, replace with whatever
I set, then adjust the fuzziness to include as much of the off-color as
I determine.

I was hoping there was a simpler way.

m-m
Anonymous
April 5, 2005 9:09:21 PM

Archived from groups: rec.photo.digital (More info?)

Chuck Forsberg wrote:
>
> I downloaded a trial version of JSC Paint Shop Pro 9.
> It includes a tool for CA. I was expecting a routine
> to realign the various colors but it appears instead to
> merely be some sort of color filter.
>
> Are all CA tools just color touchups, or do some of them
> actually realign the various colors' images?
>
> --
> Chuck Forsberg caf@omen.com www.omen.com 503-614-0430
> Developer of Industrial ZMODEM(Tm) for Embedded Applications
> Omen Technology Inc "The High Reliability Software"
> 10255 NW Old Cornelius Pass Portland OR 97231 FAX 629-0665


Hello

This is good

http://flofilters.free.fr/

It makes geometric corrections, with Magenta/Green,Blue/Yellow and
Red/Cyan. It also corrects for barrel and perspective distortion.

Mike Engles
Anonymous
April 6, 2005 1:02:30 AM

Archived from groups: rec.photo.digital (More info?)

On Thu, 31 Mar 2005 15:55:58 GMT, M-M <nospam@ny.more> wrote:

>In article <8jP2e.18737$C7.12876@news-server.bigpond.net.au>,
> "Douglas" <decipleofeos@hotmail.com> wrote:
>
>> > http://www.mhmyers.com/temp/fringe.jpg
>> >
>> > m-m
>>
>> That fringe is not chromatic abberation, it's sensor based and is a classic
>> example of the problems associated with Sony and Kodak sensors when there
>> are bright (or dull) objects against a dark (or bright) background. Other
>> sensors will also produce the effect but those two are the worst I've
>> experienced. Add it to a cheap lens and it doesn't get much worse than that!
>
>It's likely more from the lens (it's a spotting scope). It happens if I
>connect a film camera to it and I can even see it just visually without
>a camera connected.
>
>m-m

Without taking the time to view the image, I'll share my experience of
several years ago. When I first tried "digiscoping", I borrowed
several Kowa standard glass spotting scopes and they all yielded
images with color fringes. I was led to believe that WAS indeed
chromatic aberration, but right or wrong - I eventually bought a
Swarovski spotting scope with the HD glass (similar to Flourite glass
by Kowa) and that eliminated the problem entirely. All these tests
were run on the same camera, hence the same sensor.

Of course the scope and the package of tripod and case cost nearly
$2000, so you get what you pay for in this situation. I've never
looked back!!!!

Olin McDaniel
!