15 Replies Latest reply: Nov 13, 2012 1:55 PM by trshaner RSS

    LR 4.2 D600 deep shadow magenta color cast

    jarau_de

      LR4.2 gives some ugly magenta color cast on deep shadows especially at high iso pictures. Nikon Capture NX2 gives them too, but not  so heavy. If I push the shadows at iso 1600, they are all magenta. Is it related to the beta state of the D600 support? My D700 is at iso 3200 in deep shadows completely black (only luminance noise), even pushed. Is there a possibility to correct that issue with LR (high iso blackpoint correction)? The shadow color tint correction from the calibration option is not really a solution, because it does not only correct the deep shadows, so the other shadows  get a green tint.

        • 1. Re: LR 4.2 D600 deep shadow magenta color cast
          DdeGannes Community Member

          The following is copied from the release notes for LR 4.2 on the Lightroom Journal website.

           

          "Please note that the support for Nikon D600 is preliminary and there is a minor risk that the appearance of your images may change when the final support for Nikon D600 is available in an upcoming release."

          • 2. Re: LR 4.2 D600 deep shadow magenta color cast
            Jao vdL Community Member

            I don't see this with files from my D600. Can you show an example? Also, if you want I can send two profiles I created using a colorchecker that give subtly different color rendering from the built-in beta profile.

            • 3. Re: LR 4.2 D600 deep shadow magenta color cast
              web-weaver Community Member

              I don't see it neither with my D600 files.

              I shot some images at dusk at ISO 2500, there's quite a bit of noise overall but no magenta in the shadows. WB was set to Auto.

              Even at ISO 12800 there's no magenta in the shadows.

              What WB setting did you use on your D600?

              • 4. Re: LR 4.2 D600 deep shadow magenta color cast
                Astrowheat

                i also face this problem...

                _DSC0353.jpg

                _DSC0610.jpg

                • 5. Re: LR 4.2 D600 deep shadow magenta color cast
                  jarau_de Community Member

                  I think, Lightroom should have a black level adjustment, because the strength of the amp glow depends strongly on the ISO and exposure time. RawTherapee has something like that and it works quite good. The other option is, that  Adobe make this profiling for us, likewise the lens profiles. It would be a great improvement of LR against other raw converters and many users would be happy.

                  • 6. Re: LR 4.2 D600 deep shadow magenta color cast
                    jarau_de Community Member

                    I've tried DXO Optic pro v8 and I can say, that there is no magenta cast in deep shadows. The color noise reduction works much better than in Lightroom. This red-blue noise has gone completely. Very, very amazingly.

                    • 7. Re: LR 4.2 D600 deep shadow magenta color cast
                      Jao vdL Community Member

                      The purple is indeed amp glow - infrared photons generated by the electronics exciting pixels on the sensor. This can be fixed by a black level adjustment indeed. Lightroom still has this and it can be done most efficiently with the curves adjust. Just move the left bottom point slightly to the right. You can also do this in the DNG profile editor and generate a profile that does it. This is one thing that LR3 had better control over with a specific black slider. I personally see a lot less glow than the above images so perhaps there is per body variation on this. I also wouldn't be surprised if the final, non-beta profiles are better at this.

                      • 8. Re: LR 4.2 D600 deep shadow magenta color cast
                        jarau_de Community Member

                        I know, that this is so called amp glow. But DXO Optic does it with its noise removal toolbox. The trick with the curve adjustment is not a solution. I've tried it. At high iso the amp glow overlays the real image signal. That gives a magenta color cast. If you simply set the blacklevel to a higher one, you darken the image signa too. That's not what I want. If you know the amp glow noise, you can just eleminate it without touching the image signal. That seems to be the way of DXO. Lightroom has to respect that amp glow in his color noise removal toolbox. And of course it depends strongly on the ISO level. Either Adobe do an amp glow profiling and correct that automatically or they let the user decide with a pimped color noise toolbox. I don't want to switch to DXO, because LR has a much better workflow. So I hope Adobe will face this problem of amp glow and do something against it.

                        • 9. Re: LR 4.2 D600 deep shadow magenta color cast
                          ssprengel CommunityMVP

                          Commenting on the two example images:

                           

                          Amp glow, caused by warm internal components adding electrons to various areas through heat, is a given in astrophotography and is removed, along with other pattern noise using dark-frame subtraction, which doubles the exposure time, and is usually available as some type of high-ISO noise-reduction in the camera settings.  Is there a reason this form of in-camera noise-reduction was not used in the night-time exposure, shown? 

                           

                          Adobe’s raw processing doesn’t have the capability to subtract a synthetic dark-frame the may have been created by Adobe through profiling of a camera, but why should they, when the camera, itself, can do this, and be more accurate as well.

                           

                          DXO does do things differently than Lightroom, so if you need what it does, isn’t it possible to create linear-DNGs and process those, further, in LR?

                          • 10. Re: LR 4.2 D600 deep shadow magenta color cast
                            Lee Jay Community Member

                            DdeGannes wrote:

                             

                            The following is copied from the release notes for LR 4.2 on the Lightroom Journal website.

                             

                            "Please note that the support for Nikon D600 is preliminary and there is a minor risk that the appearance of your images may change when the final support for Nikon D600 is available in an upcoming release."

                             

                            Please note what is said above, as it is likely at least a portion of the issue.

                            • 11. Re: LR 4.2 D600 deep shadow magenta color cast
                              jarau_de Community Member

                              4.3 RC is out and the magenta noise remains. With the now available Nikon color modes it is a bit weaker to see, but it is still there. The color noise removal of LR does not remove this magenta noise like DXO.

                              • 12. Re: LR 4.2 D600 deep shadow magenta color cast
                                ssprengel CommunityMVP

                                I believe Adobe only profiles noise overall for an ISO range, not by regions of the sensor, which DxO may do.  Maybe in a few releases they’ll do something like this, but not for now.

                                • 13. Re: LR 4.2 D600 deep shadow magenta color cast
                                  trshaner Community Member

                                  Astrowheat wrote:

                                   

                                  i also face this problem...

                                  _DSC0353.jpg

                                  _DSC0610.jpg

                                   

                                  It appears the magenta shdow area in the above shot is confined to the bottom edge of the image.  I just discussed this on a similar post concering a Canon 5D MKII with the same issue in the bottom corners of the image. I suspect it may be due to light entering the viewfinder and leaking into the mirror box:

                                   

                                  http://forums.adobe.com/message/4843206#4843206

                                   

                                  It's simple enough to try similar shots with the viewfinder blocked. When I shoot images on a tripod I always make it a point to block the viewfinder with the Canon strap mounted blind, a hat, or even my hand to keep direct light from entering the viewfinder. The only thing between your viewfinder and the image sensor is the foam seal that the mirror rests on in the up shooting position. At high ISO even the tiniest light leak could cause fogging of the image, and it will be most visible in the image bottom edge or corners (i.e. image is upside down on the sensor).

                                  • 14. Re: LR 4.2 D600 deep shadow magenta color cast
                                    web-weaver Community Member

                                    trshaner,

                                    your post triggered a thougt: Nikon recommends that the viewfinder of the D600 be covered with the supplied viewfinder cap when shoting in Live View.

                                    I don't know if the OPs picture was taken in Live View.

                                    • 15. Re: LR 4.2 D600 deep shadow magenta color cast
                                      trshaner Community Member

                                      Live view and high ISO is also a bad combination, since it causes sensor heating and significantly raises both Chroma and Luminance noise levels.