15 Replies Latest reply on May 13, 2011 9:19 AM by compositor20

    e-pl1 yellow/green colour blotches at high iso

    compositor20 Level 1

      Hello to all members and Adobe Team.


      i use lightroom 3.3 and i have made a comparison between my 2 cameras with the same sensor , e-p1 and e-pl1 and e-p1, and while they have identical grain like pattern and rendering at high iso (which is what i was expecting since they have the same sensor and only the Anti-Aliasing filter is lighter in e-pl1), colour rendering at high iso is very different (at low iso its different but i have profiles with colorchecker and the differences are minor).


      So i will post raw files in tungsten lighting (the most demanding for high iso-.-- 1600 i mean and even at 800 i can clearly see the problems i am describing).


      Olympus e-pL1 white balance is really, but really bad.. everything turns green (its really bothering to adjust and affects low iso images too... i spent so much time correcting the green cast but there is something that i can never get right).


      There are green/yellow/orange and purple/blue blotches at high iso.... it happens in tungsten lighting and fluorescent (less so at fluorescent, but still), those green/yellow blotches appear in uniform color areas that are in shadows its like a tint and there is nothing of this sort in e-p1 at iso1600 and even much higher isos have this kind of noise well distributed by all colour channels (they are usually small blotches/spots a little to the irregular round shap but sometimes have big size and very irregular shape).


      I believe its something in the blue channel but in the green channel also!


      Reds and colours at high iso are much more saturated in e-pl1 than in e-p1 (and from imaging-resource samples and dpreview e-pl1 its one of the cameras which has more saturated colours at high iso which sometimes it looks they are clipping channels).


      By the way this is not something just related to these testfiles it happens in almost all high iso files i believe different colour rendereing/demosaic would do much better.


      Here are the raw files, the first one is Olympus e-pl1:




      The second one is Olympus e-p1:




      Notice in the blue trip Samsonite bag there are much more blue blotches with the chroma noise slider at 0 (even at 25 there is a difference in Dynamic range between e-p1 and e-pl1, when all review sites clearly say that e-pl1 is a little better at high iso even in raw, and its not just because it has more detail that you can use to kill a little grain and make things equal).


      Please dont post or use this photos as examples as they are not flattering... they are just for Adobe engineers or private testing by users not for posting in other forums.



      So Olympus cameras and Panasonic camera sensors all exibiht this problem but i have never seen something like this.... the cameras are quite good at iso1600 except all shadows have that tint even with chroma noise sliders at 40 they never disappear ... is it possible to solve the colour demosaicing and left intact the luminance one?


      Please be kind to m43 cameras since they are selling very well and i think they dont have proper support... ( i bet if this was a problem with Canon or Nikon it would be corrected in a time... we dont have coustum profiles but there is a solution for that... although for this problem we dont have better solution since its too selective and only in shadows).



      By the way in Rawtherapee i have made adjustments in channel mixer (the levels of green that the blue channel has are very high; so i took a little green (and just a tiny bit of red) and the shadow areas start getting rid of the green dots, so here it is a HINT) and there were many improvements almost making them disappear... however i want to use lightroom not rawtherapee with AMAZE demosaicing.


      Oh by the way look at Rawtherapee way of removing colour moiré with AMAze algorithm its fantastic it gives you detail back and no colour moire which shows a lot with e-pl1 in lightroom (but i know its because of lighter AA filter and its not a priority).


      Thanks for your help!

        • 1. Re: e-pl1 yellow/green colour blotches at high iso
          Noel Carboni Level 8

          compositor20 wrote:


          Olympus e-pL1 white balance is really, but really bad.. everything turns green (its really bothering to adjust and affects low iso images too... i spent so much time correcting the green cast but there is something that i can never get right).

          I could only download one file at first - the first one you linked to.  That file sharing site you used is very restrictive.


          I opened the file with Photoshop Camera Raw - not Lightroom I know, but my comments should be applicable...


          I was able to click around on various things using the White Point dropper and get a decent overall white balance in just a few seconds.  However, the colors on the wall shift from magenta to green from left to right.  I suggest that the color of the light in your room is varying.  Do you have any other test images from your E-PL1 - say from outside with something that's lit by light that's not likely to be carrying reflections from objects in the room?


          Also keep in mind that it's usually not possible to get really great color with any camera from a scene that's lighted with very yellow incandescent light.


          There are green/yellow/orange and purple/blue blotches at high iso....


          Seems pretty typical to me...  With the E-PL1 image I had no problem removing the color noise with suitable application of the Color slider in the Noise Reduction section.



          • 2. Re: e-pl1 yellow/green colour blotches at high iso
            compositor20 Level 1

            Well the white balance in olympus e-p1 with the same lighting is much

            better, there doesnt seem to be the color cast and with sodium lamps its

            really difficult to get it right  unlike e-p1.


            the green blotches are common in panasonic  blotches but my e-p1 is much

            better and yes the lighting is mixed with 2 tungsten lightings



            im not at home now but when i get home i will get one file with both cameras

            and post a rar file with both cameras


            its in the shadows


            which settings did you apply in the chroma noise slider?


            i used the HSL sliders in lightroom for saturation and i reduced yellow and

            green to -32 and blue and violet to -32 and things got better so i know its

            a problem in the blue channel (although i couldnt replicate performance of

            e-p1 it got close)


            i used raw therapee and i could minimize the problem in the channel mixer

            but it should be good without it so its the demosaicing


            if there is tungsten lighting with e-p1 the image is still good till iso1600

            because lightroom is very good at removing noise in the red channel.


            colour noise is obtrusive and olympus e-pl1 is good in luminance noise till

            iso1000 and usable till iso 2000 but the camera lacks a little detail in the

            shadows compared with e-p1



            thanks for your help

            • 3. Re: e-pl1 yellow/green colour blotches at high iso
              Noel Carboni Level 8

              I was able to convert both your images and get very similar color using the white balance dropper on the same places in the images.  I don't think it's practically possible to get absolutely identical color out of two different cameras.




              Regarding the noise, like I said, there was significant color noise in both cameras until I dialed in a fair bit of color noise reduction via the Color noise slider (e.g 25 or so), which seemed to take care of it very well.





              • 4. Re: e-pl1 yellow/green colour blotches at high iso
                compositor20 Level 1

                Well if you search in the middle of the image you will see at 100% that the open bag has those green spots where it should be gray! and near the door at bottom left of the image you will see those green spots that are very distracting because they happen in shadow areas... (and by the way the red cloth is not the same red as the e-p1 image and its noticeable even at small size).


                What white balance did you use?


                I know these are just test shots but they appear in people shots too..



                Im going to prove that ACR interpretation of olympus auto white balance in olympus e-pl1 is just horrenduos with this raw file (by the way i use this one since its one of the ones with less publicity and with the most straight forward uploading, if you know one that is better to upload tell me please).




                Now try white balance at 2850 and tint at 0 (things improve).


                Now look at the clock.. it has a contour with the wall that is green/yellow its that kind of problem (i have noise reduction in teh color at 50 and in the detail at 25 to try to mitigate its effect but still not much luck).


                Next i will go to the HSL tools in lightroom and select yellow color and select saturation tab and dial in -30 for yellow and voilá! it has reached the kind of performance that i see with e-p1 (a little worse but almost unnoticeable),.. adobe should correct this problem in lightroom 3.5 please.


                then i used the split toning slider and in the shadows i dial in hue at 340 and saturation at 10 and there was a bigger reduction in the yellow spots so its the default rendering that is a mess (by the way sometimes if i reduce saturation in the green and in the blue channel it helps a little too like -30 in each) so try to correct these please, if possible by not dessaturate the channels but with an algorithm that detects only those kinds of spots and not all yellow info like you do in the red channel so well!!



                • 5. Re: e-pl1 yellow/green colour blotches at high iso
                  Noel Carboni Level 8

                  Replying to this thread at the Admin's request to try to work out why the second image above is not showing properly.



                  • 6. Re: e-pl1 yellow/green colour blotches at high iso
                    Noel Carboni Level 8

                    compositor20 wrote:


                    well if you search in the middle of the image you will see at 100% that the open bag has those green spots where it should be gray!

                    Are you seeing something different than this?





                    • 7. Re: e-pl1 yellow/green colour blotches at high iso
                      adobe-admin Adobe Employee

                      Thanks, Noel.







                      Did they both show?



                      • 8. Re: e-pl1 yellow/green colour blotches at high iso
                        compositor20 Level 1

                        Thanks for posting those comparative images


                        in the picture 1 (the one with the bag opened) its actually the other black bag that we can see only a part at 100% and not the green bag and it shows in the opening area in the shadows


                        in the 2nd picture the one with the black/blue samsonite trip bag you can clearly see yellow dots in the outline of the image between the bag and the wall that you dont see in the e-p1 picture since they are side by side its easy to spot it


                        please try to analyse the second image that i posted since it has faces and a clock there and the shadow of the clock populated with the problem that i said and the white balance is really bad



                        its something that works if i dessaturate yelow/green

                        • 9. Re: e-pl1 yellow/green colour blotches at high iso
                          Noel Carboni Level 8

                          adobe-admin wrote:


                          Did they both show?


                          I see both images now.  Thanks for looking into it, John.



                          • 10. Re: e-pl1 yellow/green colour blotches at high iso
                            Noel Carboni Level 8

                            I discern that you feel there are two issues:  Color noise, and a poor white balance.  I'm really not seeing either as an excessive problem in any of these images.


                            There are limits to data quality at high ISO.  Noise reduction sliders are there to handle most of it, but some of it is just going to degrade the image.  The only real solutions are to shoot with better light, get a more expensive camera, or wait until higher sensitivity, lower noise models come out.


                            Not that many years ago people would be drooling over this level of image quality at ISO 1600.


                            Regarding the white balance...  Is some part of "activate the white balance dropper and click on various neutral things in the image until you like what you see" not working for you?  I didn't have a problem finding a good white balance in the image of the two women.  I found a few good spots, e.g., the pot in the china cabinet, etc.  This looks pretty natural to me.  The light seems warm, and thus the ladies are a bit redder than you might see in an image lit with a higher K light.  We also see a bit of blue in the door - which I perceive as light from a window somewhere.




                            You have to understand that if you light a scene with a combination of incandescent light and light from a window, you're likely to sense the multiple colors of light in the image.  This is true with any camera model.



                            • 11. Re: e-pl1 yellow/green colour blotches at high iso
                              compositor20 Level 1

                              thanks for your Help you are a very professional team replying fast


                              in the shot of the 2 ladys i just dont understand that if it was taken with e-p1 the white balance would be much closer to the one you post (when you have many images in different lighting conditions its difficult to check white balance in all, even syncing)... there is something wrong with the way ACR or lightroom interprets whats in the camera in auto mode...



                              now the white balance has a solution even though its difficult to find a real neutral value (i believe a value of 50R, 50B, and 50G would be neutral to use the white balance droping tool right?)

                              i think there wasnt any window light but it might i find it strange too! its only incandescent light


                              what i find strange is the area around the tower clock... the way it blends with the wall... its yellow and blotchy and i dont know why (its a little different from the shadow area between the clock and the furniture which im used to see in many cameras of all brands so its a kind of noise that doesnt bother me much)...only this one thats specific


                              could you please tell me which white balance values and tint did you have to get the imag as if



                              only dessaturating yellow would decrease those yellow/green blotches that are the trademark of panasonic sensors, but i dont want to do this in every high iso since i would shoot even to iso2000 since colors Dr and grain are +- well controlled till that level but now im using just 1000 and thinking about 800 and even then there are some images that have those blotchesi in shadow areas that i dont like... they have good quality its just that color noise is very intrusive to me and your are the best one till today i just would like that you tried something to deal with this problem since it appears in many images but much less with e-p1 and they have the same sensor (its probably related to electronics or better QC on the sensors of e-p1)...

                              • 12. Re: e-pl1 yellow/green colour blotches at high iso
                                Noel Carboni Level 8

                                You're welcome, but let me just say I'm only another user, just like you.  I'm not with Adobe.


                                Do I understand you to say that the probably you feel you have with the white balance is with the "As Shot" setting?  In other words, the result of the White Balance determination in the camera?  Is it possible you have the camera set up wrong?  Are you sure it's set to Auto White Balance, and not some other setting, e.g., Daylight?


                                The Color Temperature and Tint in my conversion were 2700 and +1.


                                Even if it IS set to Auto White Balance, I would have no trouble believing it could be as far off as 3900K.  Auto White Balance can be downright BAD.  Canon cameras, for example, are well known for making images shot in incandescent light into orange mush.  You'd almost never want to use Auto with a Canon and incandescent light.  That you sense a difference between your two cameras may just be a change in the design Olympus has put into those cameras.  I had an Olympus quite a while ago, and it tended to make everything too blue-white.


                                One of the advantages of shooting raw is that you can set the white balance in the converter, and the camera doesn't have to get its snap judgment about the color of the light in the room exactly right.


                                Almost no one relies on automatic white balance settings.  Lightroom (or Camera Raw) allow you quickly to review your image(s) so you can confirm (or remake) the white balance judgment, among other things.


                                Regarding a yellow shadow near the clock, it's quite clear there are two colors of light illuminating the room.  Look at the bluish reflections in the glasses on the table, or the bevel in the cabinet door, for example.  If not a window, was there a TV or computer on, or maybe a fish tank or fluorescent fixture?  Where the clock body blocked the bluish light, the wall looks more yellow - makes sense.


                                Regarding it looking a bit blotchy...  That's just life with high ISO photography.



                                • 13. Re: e-pl1 yellow/green colour blotches at high iso
                                  compositor20 Level 1

                                  Thanks for your help.


                                  Yes i was talking about "As shot" white balance (sometimes i dont have time to see the WB in every image and i need to trust it or when i want to show photos to family that were taken that day i must use olympus jpgs since they are much better)


                                  well in that shot it may be a differente light source in color temperature and then it would explain the green yellow shadow in the clock but how do you explain these shots in studio iluminated pictures that show the kind of noise i dont like (specialy because in the 3rd picture you will see that it usually extends over big areas in a picture



                                  teste 2 .jpg


                                  teste 3.jpg


                                  I thikin those were clearl they have those yellow blotches while the other comparable sensor doesnt have (the 2 last ones are panasonic gh-2 and panasonic g3 jpgs and since their sensors are close enough in performance it means there is a processing way of removing those yellow blotches over the midtones and i want adobe to correct it if they can and i believe they can.

                                  • 14. Re: e-pl1 yellow/green colour blotches at high iso
                                    Noel Carboni Level 8

                                    At this point I have no more to offer that I haven't already said.


                                    In summary:


                                    High ISO photography with ambient light (especially warm light) WILL show noise.  These inexpensive Olympus cameras just don't seem to be up to your noise performance expectations.


                                    You may want to look into learning how to light your photographs with flash for better quality.  That's what pros do.  I don't know if the models you have support flash.


                                    Yes, indeed there are different noise reduction algorithms in use, and I think the color noise reduction processing you're looking for already exists in Photoshop and Lightroom - simply crank the Color Noise reduction up and the color blotches will be reduced, usually at some detriment to the real color detail in your image.


                                    Sports photographers have to deal with low light and high ISO all the time - and there are cameras (usually very expensive ones) that deal with the issues you're describing much better than consumer or prosumer cameras with tiny imagers.  Look up the Nikon D3s some time, as an example.


                                    And, as always, next year's model will beat the performance of anything available today.


                                    I turn the floor over to any Adobe engineers who may wish to comment...



                                    • 15. Re: e-pl1 yellow/green colour blotches at high iso
                                      compositor20 Level 1

                                      well you were right there was a fluorescent light in the other room reflecting the 2 lady shot!


                                      i have found a quasi perfect solution and it is to slide the saturation of yellow color to -30 and the problem is corrected it makes almost all images good and without those speckles but at a cost of a little less saturation in yellow color (i will compare barroch churches golden tiles with both cameras to see if they match). so Adobe could correct that yellow saturation cast