5 Replies Latest reply on Sep 21, 2010 11:13 AM by PBoehme

    Luminance Contrast

    PBoehme Level 1

      I am just wondering if the luminance contrast slider in ACR 6.2 actually does anything (or is it a placebo).  I have tried to see what it does on numerous images and am about to go blind from pixel peeping trying to see something that it actully does.  Is there some trick to seeing what it does (something like holding down the ALT key while tweaking the sharpening sliders or the CA sliders)?

        • 1. Re: Luminance Contrast
          Jeff Schewe Level 5

          Unless you are working on high ISO raw captures, the odds are you won't be seeing much if any changes when adjusting the luminance contrast slider. If you are at 6000+ ISO (I can easily see slight changes when shooting at 12000 ISO) you may as well leave it at default.

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          • 2. Re: Luminance Contrast
            Noel Carboni Level 7

            There is one trick:  Hit the P key after making a change in a particular panel.  It will toggle between before and after.  Perhaps that can help you see a change.

             

            By the way, I just leave the Luminance Contrast slider at default myself, for the reasons mentioned above - I couldn't really see any change.

             

            -Noel

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            • 3. Re: Luminance Contrast
              PBoehme Level 1

              Thanks very much Jeff and Noel.  Both of your answers are very helpful.

               

              I generally try to keep the ISO at 400 or below for bird images for maximum sharpness.  I will occasionally go as high as ISO800 when shooting very late in the day.  With my Canon 7D, ISO 400 is quite clean and 800 is often usable if the exposure is on the money.

               

              I made some test shots at ISO 3200, 6400, and 12800 and see that the results are at least noticeable when using the luminance contrast adjustment on those images.  I have also been very pleased with the results of the Neat Image plug-in when using CS3 and believe it should also be useful after an image is imported into Photoshop CS5 from ACR.

               

              Paula

              • 4. Re: Luminance Contrast
                Robert Shomler Level 4

                PBoehme wrote:

                 

                ...  I have also been very pleased with the results of the Neat Image plug-in when using CS3 and believe it should also be useful after an image is imported into Photoshop CS5 from ACR.

                 

                Paula

                I too have long used Neat Image -- theatre onstage photos in low lighting at iso 800 to 1600.  Now with ACR's pv 2010 and new enhanced noise reduction I find I can achieve almost all needed noise reduction in ACR and only rarely need Neat Image.

                • 5. Re: Luminance Contrast
                  PBoehme Level 1

                   

                  Thanks for the reply, RWSP.  I am still having a bit of trouble with the new NR in pv2010 smearing more of the fine detail than I like when processing bird images where maintaining all of the feather detail is important.  Neat Image seems to be somewhat better in that respect although I have to also be careful when applying sharpening in NI to avoid creating halos.

                   

                  I have decided to minimize both NR and sharpening at that step in ACR and then do a small amount of sharpening in NI along with cleaning up residual noise and lastly do output sharpening using some of the techniques that I have found extremely useful from Bruce Frasers' book on Image sharpening (the original version).  I might check out the latest revision to see if anything has changed in the world of image sharpening.

                   

                  Paula