DPP Noise Reduction Settings

Discussion in 'Canon EOS' started by lotsawa, Jan 4, 2007.

  1. I wonder how those of you who use Canon's DPP set the settings for noise
    reduction (NR) when converting files from RAW. There are three settings:

    * suppress luminance noise: no, low, high
    * suppress chroma noise: no, low, high

    * suppress chroma noise (no RAW): no, low, high

    (sorry, I have the German version, but I think you know what I mean).

    I suppose the third option has no effect when converting from RAW (?).

    For the first two, I set both to "no" if the pic is shot with ISO <=200, both to
    "low" if ISO is between 400 and 800, and "high" if ISO = 1600. But this is the
    result of guessing, without really knowing what's going on there.

    I have a 400D (DRebel XTi).

    Any hints are appreciated. Thanks,
    Christof
     
  2. Hello Christof,

    I do all noise reduction in PS using NoiseNinja - the same is true for sharpening. Pretty much the only thing I use DPP for is White Balance adjustments, Picture Style and Exposure variations (I only shoot RAW). The rest is better done in PS (at least that's what works best or me)
     
  3. I use DPP for everything except image rotation (horizon straightening etc). I hardly ever used its NR features. I find my 20D sensor so good that it doesn't need NR even at ISO 1600.

    My recommendation: Leave both NR settings (luminance & chroma) OFF, except if you have an underexposed ISO 1600 image. Then you can experiment.

    You definitely don't need any NR for ISO 400 and 800 - if your images are correctly exposed.
     
  4. I did a few comparisons when I got my 400D (XTi) a month or so back. In summary, I leave the NR features OFF in DPP unless I have shot at either iso 800 and underexposed, or at iso 1600. I would say however that a well exposed iso 1600 shot remains highly useable at A3 size even without the NR.

    I think, from other forum threads, that a dedicated NR program is likely to yield even better results. (Also I do most of my post RAW conversion adjustements in PS - I only use DPP for exposure compensation, white balance and occasional NR).

    I'd recommend that you take a test shot and try the settings to see what suits you best?
     
  5. When I see comments about how clean everyone's images are it worries me. I see visible noise in my 30D images even at ISO 200. I am not used to seeing this level of noise from my Minolta 7D DSLR and I worry that something might be wrong with my neo 30D.
    Look at the bottom of this shot and tell me what you think. This was not cropped at all. Just resized and saved as a jpg. One USM pass at 50%,.5,0
    http://www.pbase.com/jhuddle/image/72466350.jpg

    Another one with only a tad bit of cropping:
    http://www.pbase.com/jhuddle/image/72135162.jpg

    Both of these have not had the exposure adjusted.

    Should I be worried.

    This is the kind of noise free image I am used to from the Minolta:

    http://www.pbase.com/jhuddle/image/60441074.jpg
     
  6. The lack of control over noise reduction in DPP is one of the reasons I don't DPP. ACR lets me tailor the noise reduction, both in finer steps, and on an image-by-image basis. Even two perfectly-exposed images of different scenes at the same ISO can need different noise reduction settings. Deeper shadows tend to show more noise, so lower-contrast scenes often need less NR than higher-contrast scenes. Areas with texture (e.g. the rough, mossy rocks in this image; this image is too small to show the texture but you can imagine what it would look like) can make noise less noticeable, as it can come across as part of the texture rather than as noise.
    As for what constitutes a normal or acceptable amount of noise, that's like asking what constitutes a normal or acceptable amount of grain in a film. I was more anal than the average person about film grain, easily finding grain in 4x6" prints from films that some other people would say were virtually grain-free in 8x10" enlargements. So I'm not surprised that I would disagree strongly with a statement that 20D images at 1600 or 800, or even 400, never require noise reduction if the shot is correctly exposed. The statement that noise levels are acceptable at these ISOs is more of a judgment call, and depends on subject matter and enlargement size. I have had images at 100 that have needed NR because they were high-contrast images and I've pulled up some shadow detail (that I couldn't have pulled up at exposure time because it would have resulted in blown highlights), and I've had images at 800 that have needed little or no NR.
     
  7. Jim, you are introducing many variables into this equation.

    Are you shooting JPG or RAW? If you're shooting RAW, you're not taking advantage of the camera's internal post-capture noise reduction algorithms, so a RAW file will always look "noisier" than a jpeg.

    On the other hand, you will get more blocking and blotching with a jpeg, especially noticeable in smoothly gradated areas of the picture.

    Sharpening before noise reduction will enhance the existing noise that is present in the photo.

    Resizing will generally reduce the visible noise, often allowing a resize of an ISO 800 or 1600 photo to look quite good without additional noise reduction.

    The severity of the recompression of the photo will affect what one perceives as visible noise.

    Generally, with the 350d/20d/30d, I start to notice objectionable noise in a properly exposed RAW file at 100% crop at ISO 400. With the 400d, I sometimes see a bit more shadow noise than with the 8MP sensors.

    Looking at your example pictures, it appears that the picture of the kestrel is extremely over-sharpened.

    The noise in the owl picture looks to be primarly jpeg recompression artifacts.

    Your Minolta may do heavier in-camera noise reduction, but it's hard to tell with resizes, etc.

    You'd have to provide maximum quality 100% crops to make much of a determination as to the cause of the "noise" in each photo- where it's introduced, where it's enhanced, where it's removed.
     
  8. I do my NR Photoshop. Going from RAW I use the RAW conversion colour noise reduction if required. Once I have it in photoshop I do luminance noise reduction using a gaussian blue layer with a surface mask generated using TRL actions. I can then paint the surface mask as needed to increase or reduce the local NR effect.

    I find this gives me more control than noise ninja and fits better with my work flow.
     
  9. Additionally I do masked capture sharpnening using a TRL action to generate the edge mask. If I need I can then modify the sharpening mask also. As pointed out above simple overall sharpening will add a lot of noise.
     
  10. Amazing bits in this thread that caught my eye:

    "...I see visible noise in my 30D images even at ISO 200..."

    "...easily finding grain in 4x6" prints from films that... grain-free in 8x10" enlargements..."

    That's nothing, I saw a movie with a kid who could "see dead people".
     
  11. They really need to take the noise reduction controls out of the preference menu and put it into the toolbar. Because it is under preferences, when you batch convert, it will apply the same noise reduction to every image. Most images don't need noise reduction anyway, but it is still annoying. If it were under the tool pallete, you could apply custom noise reduction on an individual basis. If you want to see the effects of the noise reduction there is an option to view that (sorry, I don't have it in front of me at work). But it causes delays because every image you see in the image window is converted first. If there is any noise reduction necessary, I normally use Noise Ninja.
     
  12. Hi Greg, yes, the NR controls should be part of the conversion toolbar as in ACR! What I did is to mark files that need more NR differently and then converted them in a batch using the proper settings. But I think I follow Steve's path and use ACR, although I don't find ACR very intuitive, and it lacks the picture styles. What do values of "25" and so on mean? Why is 25 the default? Ok, I have to read the manuals more seriously ... And I have idea what "luminance" and "chroma" mean as different qualities of noise.
     
  13. Christof

    I did not like ACR when I first used, but loved DPP.

    ACR got a lot better for me as soon as I defaulted all the auto boxes on the first tab to off and took control. The initial default values then are a good representation of the 'as shot' case.

    My notes at the time I changed over where "....ACR tends to a warmer and brighter interpretation." I have some comparative tests from that time here http://www.zen20934.zen.co.uk/photography/convertertests.htm
     
  14. Hello Lester (and all others),

    thanks for sharing your experience and the comparison. What changed in DPP since your review is the NR settings. ISO 1600 files from my 400D are more or less useless without some NR and I found DPP does a pretty good job here, better than NoiseNinja does after conversion (it seams NR of ACR is also quite good). NoiseNinja became more or less obsolet for me.

    I find adjusting WB easier in DPP than in ACR.

    What I noticed is that the preview in DPP differs from how the pictures look when they are opened in (or passed to) PS CS2 after conversion - but maybe I didn't set DPP's preview to highest quality.

    And what annoyes me is that DPP doesn't pass the file name when transferring the file to PS via Alt-p.

    Another disadvantage of DPP is that it doesn't cache the preview which makes looking into different directories annoying.

    Other than that, I am quite happy with the conversion quality of DPP.

    So I'll continue to try both ...
     

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