7 Replies Latest reply on Jun 18, 2015 6:24 AM by ColdForest

    Automatic lens correction?

    jacekplacek1977

      Hello,

       

      Previosly when using lightroom 5.7 the program could automatically detect the correct lens used. In lightroom I went to lens corrections => basic => marked the box "enable profile correction and the program applied the corrections to the photo.

       

      This does not work anymore after my upgrade to Ligtroom CC. It only says "unable to locate a matching profile automatically.

       

      Grateful if anyone knows how to correct this?

        • 1. Re: Automatic lens correction?
          ManiacJoe Adobe Community Professional

          Are you using the same lens as before? (Not all lenses have profiles.)

          What lens and camera are you using?

          What OS are you using?

          • 2. Re: Automatic lens correction?
            Jao vdL Adobe Community Professional & MVP

            Most lens profiles only apply to raw files not to jpg, psd or tiff, so make sure you are not by accident looking at one of those.

            • 3. Re: Automatic lens correction?
              ColdForest Level 1

              Jao vdL wrote:

               

              Most lens profiles only apply to raw files not to jpg, psd or tiff, so make sure you are not by accident looking at one of those.

              I just ran into this: after editing an image in Photoshop CC (through LR CC) I see that the resulting .tif file isn't able to match the proper profile. The profile it selected is (oddly) "close" (it selects a Nikkor 14-24mm instead of the Nikkor 24-120mm) and this suggests that it is attempting to locate a profile given the existing EXIF data (which was at least preserved during the original LR->PS->LR cycle). So, two questions here: 1) is lens correction only available on RAW images (you indicate yes, why is this?), and 2) if only on RAW why does LR allow you to apply another profile (and why does it select an inappropriate one by default)?

               

              I guess I'm also interested in why the resulting profile list for "Nikon" (in my case) is different when applying to a tif vs raw file (the latter has a much longer list of available profiles).

               

              As an aside I've been resisting this correction step prior to some PS editing sequences (in particular photomerge and/or merge to hdr) because I'd thought it better to apply this as the last step on the final PS-saved image. However, if lens correction is not available on the resulting tif file then I guess I need to change this (and are there other side effects associated with performing this correction on a set of images destined for PS photomerge/hdr)? Just thinking about this some more perhaps it *is* better to perform this correction first (at least for photomerge) since this would at least correct for things like vignetting, which would otherwise be potentially problematic during the merge.

               

              OK, I'm rambling now ...

              • 4. Re: Automatic lens correction?
                ssprengel Adobe Community Professional & MVP

                Raw profiles can correct for any and all of geometric distortion, vignetting and chromatic aberration, although nowadays, LR corrects CA by modelling it for each image and using that correction instead of something that came from profiling a lens at Adobe that might not have been identical nor mounted precisely the same.

                 

                The problem for non-raw images is that it’s impossible to tell if the image has already had corrections done to it, either by the camera, itself, or by a program such as Photoshop, or even if the image is the original sensor size not cropped off-center, all of which will cause the correction of an applied profile to be wrong. Only with an original raw file can Adobe be sure there has been no correction already applied and that the imgae data is full sensor-sized, or at least from a known set of in-camera crops.

                 

                There are a few lenses that Adobe does supply non-raw profiles for.  These are typically for cameras that either don’t’ shoot raw or where the lenses are likely shipped with the camera, so called kit lenses, so people may not know enough to shoot raw or turn on in-camera corrections.

                 

                Having said all that, it is easy enough to hack a copy of a raw profile into a non-raw profile just be changing one XML tag value from True to False everywhere it exists in the lens profile file in a text editor and then copying that file to the users-library profile area that is shared between all versions of Photoshop and Lightroom so it doesn’t get overwritten by new installs.    I don’t recall the precise tag name without looking at it, but it is something only slightly less obvious than <this-is-raw>True</this-is-raw>

                 

                As you say, generally it would be good to correct lens distortions in the raw file before sending to Photoshop, as even if you used a hacked file, things might still not be quite right because the vignetting values would be based on raw data not JPG/TIF brightness data.

                • 5. Re: Automatic lens correction?
                  Jao vdL Adobe Community Professional & MVP

                  As always ssprengel is way faster than me answering and he is again correct.

                  • 6. Re: Automatic lens correction?
                    ColdForest Level 1

                    Thanks for this, everything here makes sense. From this I can divine other rationale for the more specific points I questioned in my note.

                    • 7. Re: Automatic lens correction?
                      ColdForest Level 1

                      Jao vdL wrote:

                       

                      As always ssprengel is way faster than me answering and he is again correct.

                      You guys do an amazing job keeping up with all of these posts and between all of you you're able to provide incredibly useful and timely responses. I for one am very appreciative of this. Thank you.