24 Replies Latest reply on Jan 13, 2009 1:59 PM by Ramón G Castañeda

    Red blooming & Defringe

    Yammer Level 4
      I took some photos with my Nikon D300 yesterday which turned out rubbish. No big deal - they were just snaps, I had the wrong lens and the light was tricky. They looked awful in Bridge, even after adjustment. I put it down to over-exposure, camera shake, and cropping.

      This morning, out of interest, I looked at the same photo in Capture NX. It was still a bad photo, but it seemed to be exposed correctly, and there was noticeably less red blooming on high contrast edges.

      I've just packed away my 50mm f/1.8 lens because of regular red blooming, but it seems that I'm getting small amounts with other lenses too. Revisiting old images with Capture NX shows that the problem is not nearly as noticeable. This suggests there's something wrong with my ACR settings.

      I've now altered my defaults to -0.30 exposure and +10 clarity, vibrance and saturation - which has helped create a less washed-out appearance, out of the camera.

      I've played with Defringe, and the All Edges options seems to remove most of the blooming, and also desaturate the image slightly. But surely I should only need Defringe on over-exposed images? And why would I need it more with my 50mm lens?
        • 1. Re: Red blooming & Defringe
          Yammer Level 4
          Sorry, I should add that I'm using ACR 5.2 with a custom camera profile based on Adobe Standard beta 1.
          • 2. Re: Red blooming & Defringe
            Thomas Knoll Level 2
            Without posting the actual raw file, it is going to be hard for people here to help you.
            • 3. Re: Red blooming & Defringe
              Dennis 1111 Level 2
              Keith,

              Does your problem look anything like this?

              http://www.fredmiranda.com/forum/topic/724673

              What colorspace are you using? I ask because I suspect that using a more restricted colorspace like sRGB probably makes the problem somewhat worse by clipping the already saturated areas of the fringe.
              • 4. Re: Red blooming & Defringe
                Yammer Level 4
                Okeedokee then. Here's the dodgy photo in question:
                http://www.yammer.myzen.co.uk/D3C_6445.NEF

                the adjusted image saved as DNG is here:
                http://www.yammer.myzen.co.uk/D3C_6445.dng

                And screen shots from the two applications are here:
                http://www.yammer.myzen.co.uk/red-bloom-acr.jpg
                http://www.yammer.myzen.co.uk/red-bloom-cnx.jpg
                • 5. Re: Red blooming & Defringe
                  Yammer Level 4
                  Dennis,

                  Yes, it does look like that, but not quite as bad! :-)

                  I use 16 bit ProPhoto.
                  • 6. Re: Red blooming & Defringe
                    MadManChan2000 Adobe Employee
                    The fringing is being made more visible by the high level of sharpening you're applying to the image. (Note the halos in your CR image compared to the NX.) Also note that if you choose Camera Raw Defaults from the flyout menu the fringing is not nearly so obvious; in fact it looks much more like what the NX image looks like.
                    • 7. Re: Red blooming & Defringe
                      Yammer Level 4
                      Thanks for pointing that out Eric.

                      Although I've been very pleased with ACR reproduction since 4.5, I've recently come to the conclusion that things could be better.

                      It seems that I'm sharpening too much too early, and the custom camera profile I created from the Adobe Standard beta profile is too washed out in the highlights and has too much contrast.

                      I've now created a new custom camera profile from Camera Standard and reduced my sharpening default to 35. Skies and highlights are now better defined, straight out of the camera, with less blooming.

                      Ideally, something in between Adobe Standard and Camera Standard would be best, but I'll have to do my homework to work out how to achieve that.
                      • 8. Re: Red blooming & Defringe
                        MadManChan2000 Adobe Employee
                        Keith, just FYI, in general if your default sharpening level is over 50 in ACR that is probably too much. 25 to 45 is more reasonable.
                        • 9. Re: Red blooming & Defringe
                          Yammer Level 4
                          Thanks. I changed my default to 40 this morning, and I'm sharpening more in post-processing now. It'll probably take me a while to sort out a decent preset.

                          I spent a lot of time messing with camera profiles this morning. Although highlights were better defined using my new custom camera profile, I wasn't very happy with the new skin tones. I ended up scrapping my custom profile and using the canned Camera Standard instead.

                          I'm still not 100% happy with the results, and ideally need something between that profile and my old modified Adobe Standard beta profile. I noticed in DNG Profile Editor that the base tone curves are quite different for the two canned profiles, so I guess I'll have to manually draw one somewhere in between the two, in order to improve the contrast and retain the highligh detail.

                          I'm still very confused about the way DNG Profile Editor works. Can anyone recommend reading material for this?
                          • 10. Re: Red blooming & Defringe
                            Dennis 1111 Level 2
                            Keith,

                            If you are wrestling with getting a profile that suits you, I strongly suggest getting a Colorchecker chart, shooting it, and using it to make your own custom profile using the Profile Editor. It is easy-peasy and, in my experience, works very well. I like my custom profile better than any of the Adobe or Camera profiles (although those have been improvements over the 4.4 and earlier profiles).

                            So far I haven't even bothered to do the dual-profiling using daylight and incandescent. I just shot the one in daylight and it seems to work pretty well, even for indoor shots.

                            Now I can get skin tones and saturated reds pretty close in the same shot. Before, using ACR calibrator scripts, I could tune for skin or tune for saturated colors but not both at the same time. The Profile Editor is also much more consistent compared to the ACR calibrator scripts. It used to drive me nuts running the calibrator scripts twice on the same Colorchecker chart and getting significant differences each time.

                            The Colorchecker chart is available (either the large or mini version will work) for as low as $65. Seems like a lot of money for a piece of cardboard with colors on it but I think the time it will save you to create a neutral baseline specifically for your camera will likely be worth it.
                            • 11. Re: Red blooming & Defringe
                              Yammer Level 4
                              Hi Dennis

                              I've already got one!! I did the calibration thing last year when 4.5 and DNGPE came out.

                              I created a custom profile using Adobe Standard and a shot of my card. This is what I've been using for the last 6 months, until this week, when I noticed the improved highlights in the Camera Standard profile.

                              I tried creating another custom profile using the Camera Standard profile as the base, but it just didn't look very good, so I ended up using the profile itself.

                              I still wasn't happy, so I've gone back to using my original custom profile again. This time, however, I've been playing with the Tone Curve tab in DNGPE. I've added a sag at the top half of the curve, in order to shave a bit off the top of the base curve. So far so good. I get the colours and contrast of my original profile, and the finer highlights of the Camera Standard profile.
                              • 12. Re: Red blooming & Defringe
                                Panoholic Level 2
                                Keith,

                                if I see that what you see and complain about, then it is not blooming but very regular, old-fashioned color aberration. Particularly visible along the power line and the top of the power pole, it can be eliminated easily by Red/Cyan Fringe +25, Blue/Yellow Fringe -15.

                                I wish my fav lens would create so easily removable CA. I guess CNX does this automatically.

                                Btw, your default exposure adjustment should be -0.5 EV, except for ISO 100, when it should be about +0.15 EV.
                                • 13. Re: Red blooming & Defringe
                                  Yammer Level 4
                                  Hi G

                                  I don't think you are looking at what I see. I always correct for Chromatic Aberration, as best I can. Granted, your CA settings are best for correcting the aberration in the corner of the image, but these days, I tend to correct on high-contrast edges about a third of the way in, as CA tends to be irregular with my camera, and this seems to be the best compromise.

                                  If you look at the spire of the church and the white bits of the houses to the top right of the spire, you'll see what I mean.

                                  > Btw, your default exposure adjustment should be -0.5 EV, except for ISO 100, when it should be about +0.15 EV.

                                  Sorry, you lost me there. What are you referring to? This photo, or in general? My camera settings, or my ACR settings? And why?
                                  • 14. Re: Red blooming & Defringe
                                    Panoholic Level 2
                                    Keith,

                                    I'm sorry, the spire is so small, it has avoided my attention, for the CA is much worse.

                                    Well, there is a TINY clipping in the image (I mean real clipping, i.e. saturated pixels): 142 red and 20 blue pixels, and that happened just on the spire and on the triangular roof of one house far away. Obviously this is caused by reflection; the spire appears to be gold-plated.

                                    The following capture shows first the enlarged spire (undemosaiced raw pixels), the second one shows the clipped pixels.

                                    http://www.panopeeper.com/Demo/KeithNuttal_D3C_6445_ChurchSpire.GIF
                                    http://www.panopeeper.com/Demo/KeithNuttal_D3C_6445_ClippingOnChurchSpire.GIF

                                    The clipping caused the loss of the golden color on much of the spire, and that appears to you as blooming. In fact that, what you dislike is the true color, the middle of the spire is blown.

                                    ACR makes a clandestine adjustment of +0.5 EV to all D300 raw images, except those with ISO 100; they get adjusted by -0.5 EV, which is incorrect (the first one is correct in the amount, though it is a nonssense to do that). Therefor what you see initially does not reflect the real exposure.
                                    • 15. Re: Red blooming & Defringe
                                      Ramón G Castañeda Level 4
                                      Just an expression of gratitude to G Sch for his readiness to help. We all benefit from it.
                                      • 16. Re: Red blooming & Defringe
                                        Yammer Level 4
                                        Thanks for clearing that up, G.

                                        Yes, the CA is worse in the corners, but I was trying to illustrate the blooming effect with the image. Even properly corrected, the effect is the same.

                                        It appears that, between you and Eric, you have identified the problem exactly: the spire and white details in the middle of the image are blown, and the sharpening has exaggerated the surrounding colours (which are red brick and gold), producing an orange-red bloom.

                                        As I said in the original post, it was a rushed photograph. I chose it to illustrate two points: the blooming, which I see more with my 50mm lens; and the loss of highlight detail, compared with CNX.

                                        I now use a home-made camera profile with a tone curve which is less steep at the top end, and this helps to better preserve highlight detail, at the expense of slightly less midtone contrast. This also negates the need for the ACR exposure compensation you suggest.

                                        As it seems that the blooming is a combination of over-sharpening and over-exposure, I need to work out why this affects my 50mm photos more than those taken with my zoom lenses. I had previously decided there was something wrong with the 50mm, but it appears that I was wide of the mark!
                                        • 17. Re: Red blooming & Defringe
                                          Panoholic Level 2
                                          Ramón,

                                          I am speechless (well, not totally).

                                          Thanks for the appretiation.
                                          • 18. Re: Red blooming & Defringe
                                            Yammer Level 4
                                            Firstly, I've no idea what Ramón is on about. Is G famous or something? Or am I missing a joke somewhere.

                                            Mainly though, I'm updating the topic for completeness ...

                                            I wasn't convinced that the blooming effect was purely down to over-sharpening and over-exposure - exaggerated by it, certainly, but not caused by it.

                                            I dug out my 50mm again and fired off some photos this weekend. Looking at the photos, together with lots of old ones, I'm convinced that over-exposure is not necessary the cause of the blooming. Using Rawnalyzer, i see that most of the bloomed images are not over-exposed. Even reducing ACR to the default sharpening amount (of 25) I can still see definite blooming, albeit very subtle.

                                            One of the test images was a slanted close-up of a black and white print at f/2.8. The centre of the image is dead sharp; the top of the image shows a green bloom; the bottom of the image shows a magenta bloom. It seems that the bloom is a by-product of the lens being out of focus (due to the shallow depth of field).

                                            http://www.yammer.myzen.co.uk/_D3C67142.dng

                                            This ties in nicely with the fact that my 50mm (my fastest lens) has been giving me autofocus issues, which would explain why I might see red blooming on highlights - if the lens was rear-focussing.

                                            Now, this phenomenon is completely new to me. I wasn't aware that lenses could produce blooming when out of focus. My 50mm seems much worse than my zoom; maybe due to the much faster apertures possible. It is a cheap lens, but always gets rave reviews nontheless.
                                            • 19. Re: Red blooming & Defringe
                                              Yammer Level 4
                                              New word for the day: Spherochromatism.
                                              • 20. Re: Red blooming & Defringe
                                                don solomon Level 1
                                                Sample variation on inexpensive Nikon produced lenses can vary by 30% at the extremes. I went through 3 returns on my 50 1.8 before getting a good one. By contrast, my first 60 micro 2.8 was virtually flawless by comparison. It's a QC issue.

                                                Adobe has come a long way with the profiles in attempting to closely emulate Nikon's proprietary 'look'--but the standard is still only seen in NX2, which is what I use exclusively on my really valuable shots. It may be a bit slower (but nothing like previous versions), but it saves some very difficult and tedious tweaking in ACR/PS. But that is not to bad mouth ACR--it has improved immensely and gives me good results for 95 % of my work, thanks to Thomas, Eric, and all the others who continually fine tune it.

                                                Excellent thread, by the way.
                                                • 21. Re: Red blooming & Defringe
                                                  Ann Shelbourne Level 1
                                                  >The centre of the image is dead sharp; the top of the image shows a green bloom; the bottom of the image shows a magenta bloom.

                                                  There is another thread where someone had this problem and it was traced to the fact that they were saving their 14-bit NEFs with Compression.

                                                  Try saving them as UN- compressed; or see if Lossless Compression works safely in this regard.
                                                  • 22. Re: Red blooming & Defringe
                                                    Panoholic Level 2
                                                    Keith,

                                                    there is still no
                                                    i blooming
                                                    there. Blooming is a phenomenon of the sensor, connected to well saturation; this is plain color aberration, even in the center. For CA correction you need to enlarge the view to 300%. The only spot free of CA is between the C and L of CLUB, but already the C's top half and the L's bottom half exhibits the CA.

                                                    This lens sucks; Photozone's test too shows this, but this copy appears to be exceptionally bad.
                                                    • 23. Re: Red blooming & Defringe
                                                      Yammer Level 4
                                                      Ann: it is saved as lossless compressed, which I take to mean reversible compression. Thanks for the suggestion though.

                                                      G: I called it blooming because it surrounds objects rather than presents to one side, like in common lateral CA. I could have called it fringing, but we're splitting hairs.

                                                      I usually correct lateral CA at 400% (max in ACR), but, as I already said, what often works in one spot doesn't work in another and vice versa; I could probably get better correction with more effort, but that's not what this topic is about. In my opinion, lateral CA isn't the main problem here, spherochromatism is. I can clearly see symmetrical green fringing at the rear and magenta at the front.

                                                      All of the impartial reviews I've read of this lens are positive. It's generally held to be a remarkable lens because of its sharpness and its price. I may well have a bad copy though. It's second-hand, so I'm stuffed if it is.
                                                      • 24. Re: Red blooming & Defringe
                                                        Ramón G Castañeda Level 4
                                                        Re #18:
                                                        >Firstly, I've no idea what Ramón is on about.

                                                        That's fine. It was not directed at you, whoever you are. :|