RAW Conversion: Adobe Capture Raw vs. Canon Digital Photo Pro

Discussion in 'Canon' started by W, Oct 18, 2006.

  1. W

    W Guest

    Folks,

    I have done alot of RAW conversions (20D) with ACR. I like ACR's
    interface and the chromatic abberation correction. However, I seem to
    keep coming across situations where ACR does not do a good a job as
    Canon's RAW conversion (whether in camera to jpeg or via DPP). I have
    seen the following issues:


    - sudden light to dark tranasitions (e.g. a lampost against a bright
    sky). ACR seems to generate color artifacts whereas Canon's conversion
    significantly less so.


    - very dark areas of the image. Canon's conversion seems to generate
    smoother more 'photographic' or desireable results whereas ACR tends to

    look noisy and/or posterized. I have noticed that sometimes the way ACR
    converts,
    it creates a spike at '0' in the Blue channel histogram. DPP with the
    same image does not (even with a whole lot of tweaking, ACR still does
    this). I wonder if this is why shadows appear noisier?


    - color rendition. Canon seems to give a more neutral natural looking
    result, whereas I have seen some casts when using ACR. I typically set
    my WB to Sunlight when working outdoors, and the results seem to be
    more what one would expect with Canon's conversion, even when I use the

    'as shot' setting in ACR

    - I have also occasionally noticed less detail with ACR but this is
    hard to quantify (e.g. I had one
    image where a building reflected in the glass of another building, and
    there was noticeably less detail in the ACR image in this reflected
    area. Sharpening was off, but even with the sharpening turned way up in
    ACR, the detail was still less than the DPP conversion. Yet, other
    parts of the image did not exhibit less detail...a strange one).


    I really want to use ACR for the chromatic abberation and workflow. But
    based on my experience, I now am using DPP. Also, it would seem not
    even to make sense
    for me to consider lightroom if it is built on the same RAW conversion
    engine as ACR.


    Has anyone else seen these or other issues with Adobe Camera RAW?

    Thanks


    W
     
    W, Oct 18, 2006
    #1
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  2. W

    Jeremy Nixon Guest

    Yes, clipping of shadows will create a noisy appearance. However, the
    shadows may very well not really be clipped; what color space are you
    converting to in ACR? A *LOT* of images will clip shadows going into
    sRGB, but not with a wider space like Adobe RGB or ProPhoto RGB. You
    may be able to squeeze the range into sRGB with adjustment, though the
    quality will suffer for it.
    Canon's conversion has the advantage of knowing what 'as shot' means.
    ACR can only approximate. More adjustment will often be necessary as
    a result of the simple fact that it's a third-party conversion versus
    one designed to match the camera exactly.
    You could also use both, choosing whichever one you feel will best suit
    a given image.
     
    Jeremy Nixon, Oct 19, 2006
    #2
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  3. W

    W Guest

    Thanks for the response. I used Adobe1998 color space for both
    converters. Even when I used 'exposure' and/or 'brightness' in ACR
    making the image appear significantly lighter than the DPP conversion,
    there was still a spike at '0' in the blue channel histogram on the ACR
    converted image whereas the DPP converted image did not display such a
    spike(and by the way, I am talking about the histogram as displayed in
    photoshop on the converted image in both cases). That's why I suspect
    something is 'not right' with the ACR conversion. I guess I will use
    DPP as my default converter and ACR only when I feel a DPP result is
    lacking in some regard.
     
    W, Oct 19, 2006
    #3
  4. W

    Jeremy Nixon Guest

    What do you have the "shadows" slider set for in ACR, when you get blue
    channel clipping? Do you get it even when you set it to 0?
     
    Jeremy Nixon, Oct 19, 2006
    #4

  5. one question from my side...i've read that these express photo labs which
    (at least here) widely use Fuji 350....photo lab - by default use sRGB color
    space, so if sending to develop pics, saved in other spaces, as Adobe or
    ProPhoto may result in different colors in final developed picture...they
    also can't read embedded color space (if it is embedded in jpg, that is)..
    so, let's say i convert in ACR and use ProPhoto...then i get jpg in that
    color space. What next? When final work on them is done, convert to sRGB?
     
    Protoncek \(ex. SleeperMan\), Oct 19, 2006
    #5
  6. W

    W Guest

    yes even with the shadows slider set to 0

     
    W, Oct 19, 2006
    #6
  7. W

    W Guest

    Typically it makes sense to give a photo-lab files in sRGB space unless
    they state otherwise. So before saving your jpg, convert to sRGB for
    files destined for such labs.
     
    W, Oct 19, 2006
    #7
  8. i wonder...never tried yet...is it possible to convert jpg images? I mean,
    if i'd set to sRGB in ACR, what's the point of ProPhoto then... I guess i
    should convert to jpg in ProPhoto mode, and then convert jpg's i want send
    to lab into sRGB...?
     
    Protoncek \(ex. SleeperMan\), Oct 19, 2006
    #8
  9. W

    tomm42 Guest

    You can convert Adobe RGB to sRGB in Photoshop, but you won't get any
    more colors going the other way. So it makes sense to use Adobe RGB (or
    ProPhoto) and convert later to sRGB. Some printers do use Adobe RGB
    like a Chromira or Lightjet, so alway ask your printer. I did have some
    vacation 4x6s made at CVS recently, they said they had an sRGB printer,
    so I converted my files, everything looked flat, sent some back in
    Adobe RGB ancd these came out looking like my files, pays to
    experiment.

    Tom
     
    tomm42, Oct 19, 2006
    #9
  10. W

    Jeremy Nixon Guest

    My recommendation for "what next" is to avoid those labs like the plague
    on photography they are.

    sRGB butchers images. Almost all print processes are capable of gamuts
    exceeding sRGB, especially photographic printing processes. Use a lab
    that (preferably) supports color managed workflow, or (at least) doesn't
    require sRGB input.

    In addition to the smaller gamut, there is an issue with doing the
    conversion in working space -- if you convert from a wider-gamut working
    space into sRGB, out-of-gamut colors are simply clipped. You can't use
    "perceptual" rendering here, because there is no such thing as a perceptual
    conversion to sRGB (Photoshop will let you choose it, but it will do a
    relative colorimetric conversion anyway). If, however, the lab itself
    does a conversion from your working space into its output space, the
    conversion can be perceptual, and out-of-gamut colors can be scaled back
    rather than clipped, resulting in better output quality.

    So, avoid sRGB and the labs that require it.
     
    Jeremy Nixon, Oct 19, 2006
    #10
  11. W

    Jeremy Nixon Guest

    It sounds like you may just have images that are better suited to the Canon
    software, since it doesn't produce that problem on output. Sorry I couldn't
    be of more help...
     
    Jeremy Nixon, Oct 19, 2006
    #11
  12. W

    W Guest

    yeah, but I question why an image should be 'better suited' to a
    particular RAW converter. If I had to guess, I would guess that there
    are subtleties particular to the 20D sensor that maybe only Canon knows
    about. ACR must work for a whole boatload of different cameras. Perhaps
    whatever public data that Adobe gets from the various vendors does not
    completely describe how the sensor captures the image. Perhaps the
    transmissive characteristics of the red green and blue filters in the
    Bayer array vary among manufacturers and are not completely described
    in the public data. Or maybe they are but it is asking too much of ACR
    to accomodate such sublteties for all sensors. I really don't know, but
    I do know that I have seen deficiencies in some ACR
    conversions...enough to (at least for now) switch me over to DPP as my
    default converter. I did find a post in some other photo site
    newsgroup with similar 'complaints' about ACR vs. DPP. So at least I
    know I am not completely nuts! It is an interesting topic, but it takes
    away from photography time :(.
     
    W, Oct 20, 2006
    #12
  13. W

    W Guest

    I just did a quick check of Lightroom Beta 4....it seems to do the same
    thing as ACR :(
     
    W, Oct 20, 2006
    #13
  14. W

    W Guest

    I just did a quick check of Lightroom Beta 4....it seems to do the same
    thing as ACR :(
     
    W, Oct 20, 2006
    #14
  15. from i saw it does quite a bit more than ACR...
     
    Protoncek \(ex. SleeperMan\), Oct 20, 2006
    #15
  16. W

    W Guest

    Yes, featurewise it does alot more. I was referring to the fundamental
    RAW conversion issues I mentioned in an earlier post on this thread.
     
    W, Oct 21, 2006
    #16
  17. that's similar, yes. In fact, maybe is lightroom for normal user even too
    rich with features which will rarely be used...
     
    Protoncek \(ex. SleeperMan\), Oct 22, 2006
    #17
  18. W

    PhotoBee Guest

    I have similar experience. I experiemented with RAW+JPG using PS CS2,
    ACDSee Pro 8, and Canon's Zoombrowser 5.6c. Photos converted from Raw
    to Jpg by Zoombrowser is more vivid and smooth while PS CS2 and ACDSee
    produce flat and darker pictures. Zoombrowser produced Jpg is very
    close to the camera's JPG output.
     
    PhotoBee, Oct 24, 2006
    #18
  19. W

    W Guest

    Yes it is unfortunate that ACR has this problem. It kind of eliminates
    the usability of Lightroom since it seems to exhibit the same 'noisy
    shadow' problem. All the features in the world don't help when there is
    such a fundamental shortcoming in the RAW converter :(
     
    W, Oct 25, 2006
    #19
  20. W

    chung Guest

    The sad thing for me is I have been using ACR for the last couple years
    for converting my 300D raw photos. At first, I thought it is my camera
    that produce darker photos as I have read many threads indicating 300D
    are deliberately set to use lower exposure. Adjusting higher exposure
    in ACR will make the photo look flat. When I upgraded to 20D, the
    exposure improved but still photos showing in ACR is not as vivid as my
    friend's Nikon D200. He suggested to me to try using Canon's own
    solftware to display the RAW because he has similar experience that
    Nikon's own software shows NEF photos much better than ACR. Now I have
    to go back and re-convert my last 2 years of RAW. Fortunately, I
    didn't delete those RAWs. I am really pissed with ACR!!!
     
    chung, Oct 25, 2006
    #20
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