lateral chromatic removal software

The most infuriating (to me) lens aberration is lateral
chromatic. With digital cameras which send files to a
computer, removing the obvious color blur is a near trivial
operation. But I don't see any easy way to do in with any
common software, like Photoshop. Is there software ...
preferably freeware, or a Photoshop plugin, that does this?

Ideally it would have a table of values of correction for
each of your lenses, and for each zoom lens, the focal
length you used. The files my camera produces have this
info (lens name and focal length used) in them for the
camera maker's lenses.

I can and will reinvent the wheel of necessary myself.

With modern zoom lenses, this is THE single easiest thing to
do to improve results.

Doug McDonald

Doug McDonald wrote:
> The most infuriating (to me) lens aberration is lateral chromatic. With
> digital cameras which send files to a computer, removing the obvious
> color blur is a near trivial
> operation. But I don't see any easy way to do in with any common
> software, like Photoshop. Is there software ... preferably freeware, or
> a Photoshop plugin, that does this?
>
> Ideally it would have a table of values of correction for
> each of your lenses, and for each zoom lens, the focal length you used.
> The files my camera produces have this
> info (lens name and focal length used) in them for the camera maker's
> lenses.
>
> I can and will reinvent the wheel of necessary myself.
>
> With modern zoom lenses, this is THE single easiest thing to
> do to improve results.
>
Could you kindly post a URL to a photo which clearly demonstrates this
aberration?

--
John McWilliams

John McWilliams wrote:
> Doug McDonald wrote:
>> The most infuriating (to me) lens aberration is lateral chromatic.
>> With digital cameras which send files to a computer, removing the
>> obvious color blur is a near trivial
>> operation. But I don't see any easy way to do in with any common
>> software, like Photoshop. Is there software ... preferably freeware,
>> or a Photoshop plugin, that does this?
>>
>> Ideally it would have a table of values of correction for
>> each of your lenses, and for each zoom lens, the focal length you
>> used. The files my camera produces have this
>> info (lens name and focal length used) in them for the camera maker's
>> lenses.
>>
>> I can and will reinvent the wheel of necessary myself.
>>
>> With modern zoom lenses, this is THE single easiest thing to
>> do to improve results.
>>
> Could you kindly post a URL to a photo which clearly demonstrates this
> aberration?
>

certainly:

http://polaris.scs.uiuc.edu/~mcdonald/IMG_0104b.JPG

capitalization matters

This is made by a Canon 30D camera and the cheapie 18-55
zoom that comes with it, at 18 mm. It was saved as raw (CR2)
format, and converted to jpg with NO sharpness enhancement
and a modest contrast enhancement.

Look ... at high magnification ... at the line at the bottom
of the (portrait orientation) page. Note the pink (magenta)
and green fringes. This is the effect. Note that these don't
appear at the center. If you rescale the green image so that
it is slightly (perhaps 0.1%) smaller, the fringes would go
away and you would have a much nicer picture.

Doug McDonald

Doug McDonald wrote:
>> Could you kindly post a URL to a photo which clearly demonstrates this
>> aberration?
>>
>
> certainly:
>
> http://polaris.scs.uiuc.edu/~mcdonald/IMG_0104b.JPG
>
> capitalization matters
>
> This is made by a Canon 30D camera and the cheapie 18-55
> zoom that comes with it, at 18 mm. It was saved as raw (CR2)
> format, and converted to jpg with NO sharpness enhancement
> and a modest contrast enhancement.
>
> Look ... at high magnification ... at the line at the bottom of the
> (portrait orientation) page. Note the pink (magenta)
> and green fringes. This is the effect. Note that these don't appear at
> the center. If you rescale the green image so that it is slightly
> (perhaps 0.1%) smaller, the fringes would go away and you would have a
> much nicer picture.

http://www.camerasunderwater.info/op...nscorrect.html
http://www.panotools.info/mediawiki/...rrection_model

BugBear

bugbear wrote:
>
> http://www.camerasunderwater.info/op...nscorrect.html
> http://www.panotools.info/mediawiki/...rrection_model

Missed a good one:
http://hugin.sourceforge.net/tutorials/tca/en.shtml

BugBear

bugbear wrote:

>
> http://www.camerasunderwater.info/op...nscorrect.html


Thanks! That's what one needs for Photoshop.

Works fine.

Still, it would be good to have a standalone program that
gets the necessary paramaters from the data file and
a file with parameters for your lenses.

The camera/lens people should supply this. In fact,
it should be an automatic part of their processing!

Doug McDonald

Doug McDonald wrote:
> The most infuriating (to me) lens aberration is lateral chromatic. With
> digital cameras which send files to a computer, removing the obvious
> color blur is a near trivial
> operation. But I don't see any easy way to do in with any common
> software, like Photoshop. Is there software ... preferably freeware, or
> a Photoshop plugin, that does this?
>
> Ideally it would have a table of values of correction for
> each of your lenses, and for each zoom lens, the focal length you used.
> The files my camera produces have this
> info (lens name and focal length used) in them for the camera maker's
> lenses.
>
> I can and will reinvent the wheel of necessary myself.
>
> With modern zoom lenses, this is THE single easiest thing to
> do to improve results.
>
> Doug McDonald

Well, there is, but it's not free. Try http://www.dxo.com

Having said that, DxO reduces and nearly eliminates not only CA, but
barrel/pincushion and other lens distortions almost universal with zoom
lenses. You can set it to maximize highlight recovery if the shot is
partly blown, among a lot of other features.

It has correction files for many slr lenses and camera bodies, and a few
high-end compacts as well.

It will correct direct from RAW or jpg files, outputting the results as
either jpg, tif, or DNG files, your choice, and it runs automatically.
Just point it at your source folder, name your destination folder, set
up your required parameters, and hit the go button.

I use it with my 300D and 17-85 USM IS lens, with incredible results.
The 17-85 by itself isn't too hot at the wide end, with barrel
distortion and CA, but DxO makes it look like an 'L' lens.

A satisfied user,

Colin D.

--
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