7 Replies Latest reply on Oct 2, 2014 2:30 AM by jophotoshop

    Lens correction

    jophotoshop Level 1

      Dear all, using the same jpg image, I used two ways to apply Lens correction.

       

      1) <In PS> Open jpg file in PS and camera raw filter> lens correction> Manual> Full. Result = excellent straight.


         ScreenHunter_193 Sep. 23 23.14.jpg

        

        2) Open the same jpg file in Bridge and Command R to get into Adobe Camera Raw. Using lens correction> Manual> Full. Result = as following

      ScreenHunter_192 Sep. 23 23.08.jpg

      It is noted that other modes are ok, only Full 'distorted' so much that it show transparent background.

       

       

       

      I am using Full because works perfectly (got the perspective I want) when using Camera Raw Filter (Result 1). Can anyone explain why are there such big difference in result 1 and 2?

        • 1. Re: Lens correction
          ssprengel Adobe Community Professional & MVP

          Can you supply the original JPG, please, using www.dropbox.com?

          • 2. Re: Lens correction
            jophotoshop Level 1

            Sure, please provide me with your ID ^^.

            • 3. Re: Lens correction
              jophotoshop Level 1

              Dropbox - 06_Building copy.jpg

              Let me know if you can get it.

              • 4. Re: Lens correction
                ssprengel Adobe Community Professional & MVP

                I asked for your example file to test with the latest updates of everything and I'm seeing the same thing you are, where the Camera Raw Filter in PS CC 2014.1 is different than the ACR 8.6 plug-in hosted PS CC 2014.1 and the plug-in is the same as in Lightroom 5.6:

                 

                I cannot explain why the Camera Raw filter is different.

                 

                Thanks for the example photo.  I am passing on this forum discussion to Adobe and see what they say.

                • 5. Re: Lens correction
                  jophotoshop Level 1

                  Please go ahead. ^^

                  • 6. Re: Lens correction
                    ssprengel Adobe Community Professional & MVP

                    Photoshop and LR/ACR are different because of the differences in working spaces, which dictate the color numbers that the algorithms are looking at.  You were having ok results in PS's CR Filter.  I was too, until I converted your image from my PS's internal working space of ProPhotoRGB to sRGB.  Then I got a worse perspective but the opposite way from LR/ACR:

                     

                    Eric Chan is a camera raw engineer at Adobe--you'll see his name in the list if you do (Help /) About Plug-ins / Camera Raw.  Here is Eric's response when I asked him about the differences you (and I, above) were seeing after observing I could see differences in PS's CR-Filter if I converted one colorspace to another.

                    Yes, the results in ACR Filter will depend on color space (and bit depth). 

                     

                    In general, Upright is (very) sensitive to both the input data, and how the code is built.  Change a single pixel in the input image, and you can get a different result.  Change the instruction ordering/scheduling, and you can get a different result.  This means Mac and Windows builds may produce different results, because Mac and Windows have different compilers; same is true between 32-bit and 64-bit builds (e.g., on Windows), since the instructions are different.

                     

                    For these reasons, you should not actually expect that invoking Upright will produce the same results, under different circumstances / entry points.  However, it is expected that once Upright has computed a result on a particular image, wherever you take that image afterwards (Mac vs Win, ACR vs Lr), it will always continue to look the same -- i.e., the computed transform/correction will remain the same.

                     

                    Eric

                     

                    So it's not a bug that things are different, at if the workspace and therefore the internal pixel numbers are different, which is true between LR/ACR and PS-Filters.

                    • 7. Re: Lens correction
                      jophotoshop Level 1

                      Thanks aot. Eric Chan thanks too.

                      Excellent explaination.