14 Replies Latest reply on Oct 29, 2012 11:44 PM by Andrew_Hart

    Cromatic aberration not corrected in NEF image

    Miljacc

      I have noticed one thing in regard the chromatic aberration. I am using Nikon D7000 camera, set to take NEF+JPG.  Watching the images in PSE(10), I can clearly see the aberration in the NEF image, while JPEG looks clear.  Watching the images in Nikon's View NX2, both NEF and JPEG are without the visible aberration.  D7000 camera supports the chromatic aberration correction. My conclusion is that JPEGs look good in both tools, since a camera processed it before the image download. NEF image is by definition uncorrected, but the file probably contains information needed to remove the aberration, which is I suppose well interpreted by View NX2 and ignored by Adobe ACR.  Could my conclusion be correct, or am I missing something?

        • 1. Re: Cromatic aberration not corrected in NEF image
          JimHess Adobe Community Professional & MVP

          I am not fully understanding your workflow. Have you opened the NEF images in ACR and used the chromatic aberration correction? If not, the correction you are seeing in the JPEG image might be applied by the camera, and that could be one of the settings not read by ACR. If that is the case, then you could enable chromatic aberration correction and then save new camera defaults. Then ACR would automatically apply the correction to new images.

          • 2. Re: Cromatic aberration not corrected in NEF image
            Yammer Level 4

            I don't use PSE, so someone would have to confirm this, but AFAIK, PSE doesn't support the advanced features of Camera Raw, and I think this includes CA correction.

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            • 3. Re: Cromatic aberration not corrected in NEF image
              JimHess Adobe Community Professional & MVP

              Oh, that's right. I'm so accustomed to Lightroom and Photoshop that I forgot about ACR limitations when using it in Photoshop Elements.

              1 person found this helpful
              • 4. Re: Cromatic aberration not corrected in NEF image
                Miljacc Level 1

                So ACR with PSE is then limited with functions in comparison with ACR working with Lightroom or Photoshop. I always thought that ACR behaves the same, irrelevant to the application it works with. Obviously wrong. Thanks a lot!

                • 5. Re: Cromatic aberration not corrected in NEF image
                  ssprengel Adobe Community Professional & MVP

                  ACR in PSE uses whatever the ACR defaults are for your camera.  The problem is you cannot enable Auto CA Correction using the ACR with PSE.

                   

                  HOWEVER (on Windows), you can edit the ACR defaults files manually with Notepad to enable Auto CA Correction.  The defaults are stored under your users folder:

                   

                  C:\Users\your-user-name\AppData\Roaming\Adobe\CameraRaw\Defaults\Default_gubberish.xmp

                   

                  Each file contains the camera-raw defaults for a different model/serial/ISO combination, depending on how finely-grained your defaults are.  If you’ve only ever had PSE on your system then they would only be by camera-model.

                   

                  To find the one for your camera, look for the KeyString tag near the top that matches your D7000.  Once you have the correct file, look for the AutoLateralCA tag and change its value from 0 to 1, then save the file.

                   

                     crs:AutoLateralCA="1"

                   

                  For AutoCA to be a setting, you need to be running PSE10 with ACR 6.7 or PSE11 with ACR 7.1/7.2.  The ProcessVersion tag in the Defaults file should say “6.7” indicating PV2012.

                   

                  If you have one of these combinations, then to add this setting to your D7000 Defaults file open a new D7000 NEF, click on the little camera tab in ACR and set your Process Version to 2012, then click on the little menu icon at the right of the title bar and choose Save New Camera Raw Defaults.  This should update the Default file with all the PV2012 tags, of which AutoLateralCA is one.

                  1 person found this helpful
                  • 6. Re: Cromatic aberration not corrected in NEF image
                    JimHess Adobe Community Professional & MVP

                    Although it is the same plug-in, it behaves much differently when running with Photoshop Elements. It is that way by design. You might want to consider getting Lightroom and using it with Photoshop Elements as your pixel editor. It's a good combination, and would give you all of the raw editing capabilities that ACR has when running under Photoshop.

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                    • 7. Re: Cromatic aberration not corrected in NEF image
                      ssprengel Adobe Community Professional & MVP

                      I second the idea about using LR instead of ACR in Elements.  You can still use Edit In Elements from within LR.

                       

                      LR has the more advanced defringing controls or moiré correction adjustment brush that can be used to correct fringes that come from bright edges in front and behind the plane of focus.

                      • 8. Re: Cromatic aberration not corrected in NEF image
                        Miljacc Level 1

                        Thanks a lot gentlemen, I am eagerly waiting to do the edits myself and check tre result.

                        • 9. Re: Cromatic aberration not corrected in NEF image
                          Miljacc Level 1

                          I experimented a bit with the xmp files assigned with particular NEF images.

                          I changed crs:AutoLateralCA="1" and I got a significant improvement.

                          I haven't yet edited the Default_gubberish.xmp, assuming that the result (for experimentation) would be the same.

                           

                          The result I got is however a bit different, when comparing with View NX2. I can't yet say if any is better or worse, just different. It is now puzzling me a bit, so I would like to investigate it further.

                          I have noticed  that Nikon software offers correction of both: axial and lateral CA, while I can find only lateral CA variable in Adobe xmp file. That will be one thing that I would like to look into.

                          • 10. Re: Cromatic aberration not corrected in NEF image
                            Yammer Level 4

                            Miljacc wrote:

                             

                            The result I got is however a bit different, when comparing with View NX2. I can't yet say if any is better or worse, just different. It is now puzzling me a bit, so I would like to investigate it further.

                            I have noticed  that Nikon software offers correction of both: axial and lateral CA, while I can find only lateral CA variable in Adobe xmp file. That will be one thing that I would like to look into.

                            Firstly, getting different results between NX2 and CR is to be expected, just as it's to be expected to get different results from any other Raw converter. This is because every application works with the raw data differently, so the interpretations are slightly different. Which one is best is usually down to a matter of personal taste. There is no right or wrong way to convert from Raw; just different ways, although lots of people seem to think that the camera manufacturers' processes are the right way.

                             

                            Secondly, I'd be interested to know how Nikon corrects axial CA, because, as far as I know, it can't be done in PP. Sure enough, you can minimise the effect using Defringe processing, but that's not really fixing the problem so much as compensating for it. BTW, there is a Defringe tool in CR, if you're interested.

                            • 11. Re: Cromatic aberration not corrected in NEF image
                              ssprengel Adobe Community Professional & MVP

                              Here is a blog post by Camera Raw engineer, Eric Chan, describing the new defringing controls in Camera Raw under Photoshop and Lightroom:

                               

                              http://blogs.adobe.com/lightroomjournal/2012/04/new-color-fringe-correction-controls.html

                               

                              The user-interface for these controls is only available in Lightroom and Camera Raw with Photoshop.  The XMP settings are near the one for Lateral CA so you may be able to blindly adjust them in ways that help but it is much easier to do so when there is visual feedback.

                              • 12. Re: Cromatic aberration not corrected in NEF image
                                Andrew_Hart Level 2

                                My understanding from reading Eric Chan's article is that ACR (as from 7.1) and Lightroom (as from 4.1) can indeed now compensate for axial (aka longitudinal) chromatic aberration. I have proved that to my own satisfaction by correcting the purple colour (in front of the point of focus) and green colour (behind the point of focus) in images of lens tests designed to establish whether lenses are front or back focusing.

                                According to the physicist's comments at the bottom of the article there is a third type of CA known as OOF (out-of-focus) CA which is inherent with glass lenses and which cannot be corrected except by stopping down.

                                He seems to think that Eric Chan does not appreciate the distinction. I certainly don't.

                                Does anyone else have anything to offer on this apparent distinction?

                                • 13. Re: Cromatic aberration not corrected in NEF image
                                  Jeff Schewe Level 5

                                  Andrew_Hart wrote:

                                   

                                  Does anyone else have anything to offer on this apparent distinction?

                                   

                                  I think the comment is confusing Lateral/Longitudinal CA with Spherical Aberration which isn't really a chromatic abberation...read this.

                                  • 14. Re: Cromatic aberration not corrected in NEF image
                                    Andrew_Hart Level 2

                                    Thanks for that reference, Jeff.

                                    The author of that article, Paul van Walree, does indeed appear to distinguish spherical aberration from the two (only ?) types of chromatic aberration, namely lateral (or transverse) and longitudinal (or axial).

                                    His link to "longitudinal" in your referenced article (which is about spherical aberration) takes you to a separate discussion of Chromatic Aberration where he has this to say:

                                    "Longitudinal chromatic aberration often operates in tandem with spherical aberration to shape the bokeh of a large-aperture lens. The combined effect of longitudinal chromatic aberration and spherical aberration is also known as spherochromatism [7,8]."

                                    He also says this in a sidebar: "Strictly speaking color artifacts in out-of-focus parts of the image should not be called chromatic aberration, since the aberration is only defined for the plane of focus."

                                    Perhaps our physicist was not entirely correct himself

                                    For anyone else feeling inquisitive, these articles by van Walree are very interesting.

                                     

                                    Message was edited by: Andrew_Hart