Skip to main content

Brightness Noise Artefacts

Comments

67 comments

  • Keith R
    Top Commenter

     It seems to me it's related to the sensor layout (demosaic) + the sharpening and denoise.

    Yep, and in my experience, very strongly related to sharpening.

    This is a 200% crop of a 2500 ISO Canon 1D-X file, a much older camera than the Sony, and one which - if Sony fundamentalists are to be believed (I don't) - has a far inferior sensor.

    NR at default, and all global sharpening disabled:

     None of that chequerboard artefact nonsense here (and feel free to muck about with the crop to try and bring them out by boosting levels, contrast and whatnot - you still won't see it.)

    Now, add some sharpening:

    This is precisely why I switch global sharpening off in Capture One - I was complaining about these artefacts when the old forum was still a thing, around Capture One version 14, IIRC. 

    Applying sharpening (or the Clarity "Structure" slider in my case) selectively is the only way to go.

    1
  • BeO
    Top Commenter

    EtMRS,

    But the support answer ! He says that I must buy the new version PL5 that solve many issue ! 

    And that reminds us of what other raw converter company? :-)

    1
  • SFA

    The Noise Reduction you have applied on the first image but not the second looks like it is uncovering some odd effects in the original interpretation of the data and making it more visible.

    I think you may need to check the visibility of the effect right the way through your process steps to see whether it is created from the processing or exists in the original interpretation of the source file.

    You might be able to use something like the colour editor tool to smooth the blue area to a more consistent colour and remove the artefacts (Skin Tone adjustment tool can be used for very fine tweaking of any colour) but if they are from the original data interpretation it may not help to "smooth" the appearance that much.

    Viewing at 100% is the right thing to do but have you checked whether the result carries through to whatever size your final output will be at whatever resolution you plan to use?

    0
  • gb

    Have to agree with SFA, artifacts seem to be in both images,
    just more disguised by the grain in the second one.

    0
  • BeO
    Top Commenter

    Agree with both.

    This is the typical pattern I often see in C1 if noise reduction values are set too high, this is how their algorithms work.

    Don't overdo the luminance (brightness) noise reduction value, also try to dial back the Detail slider and find the right balance.

    And when you zoom to a level comparable to your final output (or make a test export), this usually looks good, at least much better than 100%. In the end, that's what counts, not  the 100% view (see SFA's last sentence).

    Allow a little bit of luminance noise (and sometimes even color noise doesn't hurt in the final image size or print, but here I would be more careful). Add grain with the grain tool if you like.

    0
  • Matthias Roßkopf

    @SFA

    The image only got the lens correction and camerea settings from C1. Smoothing the colour with the colour editor tool was not successfull also with skin tone tool. I have now also exported to some jpg files and there you can also see the artefacts (the vertical and horzitonal short bars)
    I have right now never tried to print a image like that, so I can't tell that result.

    @BeO

    That's right if you don't overdo the noise reduction values it looks good but somethimes its still to noise.
    Ok maybe I should create some test prints to see the final results. For digtial use it is visibal without zooming in.

     

    Suggestion:

    Maybe it comes from the ISO2000 from the camera? I use a Sony A7 II

    0
  • BeO
    Top Commenter

    Matthias,

    I can't argue with you nor against you regarding your statement that sometimes it is still too noisy, because to some extent this is very subjective.

    Fact is that C1 has certain methods how to demosaic raw images and how to apply sharpening, local contrast, noise reduction algorithms, etc., and this all influences the result for the image in question, and it provides you with tools and sliders to finetune this.

    These algorithms work great on some images (mostly on images with not too much noise) and less great on other images, or image areas, but again, this is a quite subjective matter. I am not very averse to some noise, if it is not too coarse, so I would try to find a balance with luminace noise reduction, details, sharpening radius, amount and threshold, and the structure sliders. Sometimes I locally adjust the background, especially if it is unsharp (bokeh) or uniform as in your blue night sky.

    But, if you have another raw converter at hand, you might prefer the noise reduction and overall image quality over C1, for this particular and similar images. I remember having preferred LR for one or the other high-noise image due to the noise handling resulting in finer grain. I prefered this even over the highly praised DXO Prime NR, which was resulting in images painted by a comic artist, imo. All subjective. In most other aspects, for most images, I like C1 image rendering more. It usually result in more natural rendering, even if some noise is present (but I avoid creating artifacts).

    But there are also specialiced noise reduction apps. Choose the right tool (raw converter or NR application) for the job, and this is sometimes a hammer and sometimes a screw-driver, and only you can judge what tool that should be.

    Yes, without doubt ISO 2000 with this old camera in dark and even parts results in higher noise than ISO 100 in daylight with a newer camera, but the artifacts you see originate from how C1 algorihms work, imo. Did you increase the exposure or the HDR shadow slider then noise becomes more visible too.

    0
  • Keith R
    Top Commenter

    Maybe it comes from the ISO2000 from the camera? I use a Sony A7 II

    2000 ISO isn't high, even for a relatively old full frame camera. 

    What are your sharpening settings?

    0
  • ---

    this converter increases local contrast without user control on default so when you add luminance NR which also adds sharpening (!) artefacts get without surprise more visible.  just look at what NR does to the branches btw. only solution try to live with some noise when using c1.  this kind of artefacts are also a c1 speciality I do not see with other converter and it seems they are aware of this issue as they add noise as default for high iso to mask the problems. 

    0
  • Propheticus

    Out of interest I tried to spot the same. Comparing an image (ISO 3200) in C1 and RawTherapee shows the same horizontal/vertical patterns when zooming in. It seems to me it's related to the sensor layout (demosaic) + the sharpening and denoise. Especially the Chromatic (colour) noise. 
    Unaltered there's clear patches of iso noise in different colours, which to be honest C1 manages to remove very effectively. The below examples are zoomed in 200% on a green leaf. 

    With sharpening and noise reduction at defaults in C1, green:

    With only exposure compensation in RawTherapee, coloured patches most obvious the blue:

    Dragging all sharpening and noise reduction sliders to 0 in C1 looks very similar btw.

    0
  • BeO
    Top Commenter

    How does it look if you crank up the noise reduction in both apps?

    0
  • Propheticus

    Cranking up to max did not compare well, RawTherapee allows to go more extreme. Full slider right noise reduction turns it into a blur. 

    To be somewhat fair I: enabled default sharpening and local contrast in RT, then noise reduction luminance 50, luminance detail 50, chrominance 30 (defaulted to 15). In C1 I removed my default Clarity/Structure setting and reset the base characteristic (camera/film) curve.

    Freehand screengrabs, so forgive size difference, both at 200%

    C1 luminance 100, detail 50, colour 100:

    RT, luminance 50, detail 50, chrominance 30:

    0
  • Propheticus

    Found it (Laplace edge detect):

    Sorry, just being obnoxious now... saw a challenge in  "feel free to muck about" :P

    0
  • ---

    this has nothing to do with sharpening the base of the problem is the c1 demosaicing which is simply unable to render smooth areas without artefacts in high iso images ! this is a comparison with dp but also arc is similar clean and artefact free.

    0
  • ---

    another example, this is an extrem push of +4 stops @ 6400 iso and it demonstrates how far behind c1 is now regarding NR. 

    0
  • Keith R
    Top Commenter

    this has nothing to do with sharpening

    Of course it has - it only becomes a problem when sharpening brings it out.

    I'm well aware that other converters don't produce the artefact (as I suggest up the page, I was railing against this problem eight Capture One generations ago, and used examples from other converters to make my point) - but we're not talking about other converters, we're talking about how to mitigate it in Capture One, and the fact remains: if you want to see it, sharpen the file.

    0
  • Keith R
    Top Commenter

    I was complaining about these artefacts when the old forum was still a thing, around Capture One version 14, IIRC. 

    I tell a lie - it was version 6!

    https://support.captureone.com/hc/en-us/community/posts/360012212657/comments/360002124258

    ...isn't nearly enough of a temptation to make the step to Pro 7, especially when in terms of IQ improvements from 6 to 7, Phase One is again promising more than it delivers - new bells and whistles as usual, but the chequerboard demosaicing artefact is still there in the new engine...

    And even then, some things were apparent:

    https://support.captureone.com/hc/en-us/community/posts/360012172857/comments/360002616578

    The problem I'm seeing - and "problem" is the word - is not with Chroma NR (I've always been very happy with Cap One's Chroma handling), it's the "chequerboard" effect caused by the demosaic, with a nominal amount of Cap One sharpening applied, even at lower ISOs.

    The take-away? There's nothing new about this, CSP - and sharpening is inextricably linked with the seriousness of the problem.

    True then, true now.

    0
  • BeO
    Top Commenter

    In most of my images I experience the below artifacts (two variants at the bottom) with too high values for NR Luminance and Details sliders, sharpening (or structure) can bring this out even further. If the NR algorithm is part of the demosaic I don't know.

    0
  • ---

    Of course it has - it only becomes a problem when sharpening brings it out.

    hm, but the artifacts have still to be there in the first place to be revealed with usm. reality is that other converter do simply a much better job cleaning up this artefacts than c1. 

    and yes it is a very old issue without much improvements over the years c1 demosaicing is still inferior when it comes to rendering high iso images but as in the past  they seem not willing or able to address it.

    0
  • ---

    ....NR algorithm is part of the demosaic I don't know

    probably not but demosaicing is more than just de-bayer as far as I understand all kind of processing is applied before a file is displayed.

    "detail" seems to control a kind of sharpening on the pixel level but the checkerboard artefacts are clearly caused by NR. at the end what matters is the overall performance and how demosaicing and all tools interact and this does not look good here. 

    0
  • ---

    the NR problem was  discussed again and again for years, did something change ? yes it got a little better years ago  but in comparison to other plugins and solutions it was even then not really great.  now it's undeniable bad and what many don't see is that  it does not only impact high iso work but also low ISO shots when you try to maximise DR and lift shadows. 

    I think the c1 team does simply not have the brain power to fix this and they are only focused on half baked tools to compete with LR .  but there are many great options available today when you want to stick with c1 for other reasons.

    0
  • BeO
    Top Commenter

    NX Studio - NR OFF

     

    NX Studio - NR Normal:

     

    NX Studio - NR High:

    0
  • BeO
    Top Commenter

    Affinity Photo (zoom 320%)- Luminance NR OFF:

     

    Affinity Photo (zoom 320%)- Luminance NR 20%:

    0
  • BeO
    Top Commenter

    The default from C1 is not so bad actually:

    (zoom 300%)

     

    0
  • BeO
    Top Commenter

    There is no default in darktable (too many denoise tools) but I think if I fiddle for one hour then I can find a similar result at 300% zoom.

    Anyway, zoom level 33% on my 1920k monitor (which is roughly dpi 300 when printed) there is nothing overly distracting with C1 default settings, and the differences of the other converters are not so evident either.

    But yes when upsizing the image, a better NR would be desirable. Are there tools which fit in a C1 workflow?

     

    0
  • BeO
    Top Commenter

    DXO  DeepPrime default setting (40 )
    300%, after export to jpg and loaded in C1 because preview in not available in DXO:

    As far as noise is concerned, this is the best of the converters I've tested with this image (C1, NX Studio, Affinity, darktable)

    0
  • ---

    looking at your samples I think affinity with different settings allowing some noise left would outperform c1 as it renders a finer more uniform noise compared to c1.  ( L higher up to 100 / LD 50-100 / LD around 50 )

    being equally good or a just below average  is not right for the most expensive raw converter on the market imho. considering the overall quality I think a dxo dng workflow is the best option for c1 user who process a lot of high iso images, in the past I did also use the topaz plugin but can not say how good or useable the dng files are from their current version but it is worth considering .  

    ( we can learn a little about how the c1 NR and demosaicing interact when you feed c1 for example a affinity processed file without NR and sharpening.  in this case at  higher NR settings c1 produces this characteristic pattern but interestingly more random )

     

    0
  • ---

    dxo is a class for its own, but it would be a big step forward when c1 would even match adobe ! 

    0
  • BeO
    Top Commenter

    Affinity: NR can't get rid of the color noise in the yellow wall above. And the luminance noise doesn't get better than C1 either with your suggested settings nor with fiddeling around, though this is a bit subjective.

    So, then I developed the raw file in Affinity, and exported to tiff which I imported to C1.
    Without NR and without sharpening Affinity creates a pattern like a fisher net (50px or so) which can look like broad stripes depending on the zoom level (e.g. 100%). T
    his structure is created where there are clusters of green from the demosaic and remain as luminance patterns after color noise reduction. This is visible in AP and even more so in C1 without luminance NR in C1, with and without color noise reduction in C1.

    C1 color noise reduction works good on this AP tiff,  C1 luminance noise reduction too, but when I almost removed the fisher net structures then other image details vanish too.
    So, interesting idea but the result is not very good.

    Learned (of confirmed): The C1 luminance NR tries to keep structures if it thinks there are image structures , but it keeps also noise structures, the Detail slider emphazises them.

    How big the differences between Affinity -> print or C1-> print at 300 dpi really are would have to be tested.

    What I like about DXO DeepPrime is that I can lift more shadows with a lower noise penalty (mainly in other, darker areas of that image), which increases my choices, my editing "envelope".
    It's actually better than the watercolor effect I remember from the DXO Prime a few years ago, though even the deepPrime tends to look a tad unrealistic too, but not so much. With different value settings (and maybe some editing in C1, incl. adding grain :-) it might result in a low noise, "realistic image" quality.

    I think I will investigate this workflow further, including the DXO dng import into C1.

    0
  • ---

    So, then I developed the raw file in Affinity, and exported to tiff which I imported to C1.
    Without NR and without sharpening Affinity creates a pattern like a fisher net (50px or so) which can look like broad stripes depending on the zoom level (e.g. 100%). T
    his structure is created where there are clusters of green from the demosaic and remain as luminance patterns after color noise reduction. This is visible in AP and even more so in C1 without luminance NR in C1, with and without color noise reduction in C1.

    this is strange don't see this with my sony files.

    Learned (of confirmed): The C1 luminance NR tries to keep structures if it thinks there are image structures , but it keeps also noise structures, the Detail slider emphazises them.

    always thought detail is something more sophisticated but it seems just another micro contrast enhancement. so in fact most of the weird pattern comes von NR and not from the demosaicing as I thought.

    How big the differences between Affinity -> print or C1-> print at 300 dpi really are would have to be tested.

    there may not be a lot of difference.

    what I like most about dxo that the files look natural and smooth compared to c1 which is rather digital in my view especially with high iso. a dding some noise to the dxo images is for sure a good idea or maybe you try a lower settings 20 - 30 ?

    think they should rename the NR tool to "art filter" .  this are extrem settings but they demonstrate how NR works. lower luminance levels are blurred but the midtons and up get sharpened, also interesting in this sample is the massive color and contrast shift which is already visible at  moderate values.  this explains why processing artefacts are unavoidable.

    0

Please sign in to leave a comment.