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Thread: Converting to dng

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    Senior Member Robert Campbell's Avatar
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    Converting to dng

    There's a school of thought that says you should convert raw files to dng, as dng is a format of the future; and you should archive the original raws for the time when a better converter comes along.

    So, are there any disadvantages in converting to dng; does the process change anything in the raw file? -- is there any demosaicing required for the change in format?

    And if there is no disadvantage in raw > dng, then why don't we all do it all the time?
    Sláinte

    Robert.

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    Subscriber Member Streetshooter's Avatar
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    Re: Converting to dng

    I use to convert everything to dng. Now with the DP1 & DP2
    I just keep the raw filesas they don't convert well. In time
    if Adobe fixes the converter, I will go back and convert everything.
    I attended the seminar with Adobe in NY years ago and learned
    That dng is the future. I still believe that.
    I would suggest you keep your raw files backed up offline
    just in case.
    There is no degradation to the converted files. They may be
    Smaller but that's because they don't need that stupid sidecar.
    Don

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    Re: Converting to dng

    Hi Robert
    I do it - I've really looked hard to compare the Aperture conversions from the original with those from the .dng, and I can't see any difference.
    I do it with both Olympus .orf files and Sony .arw files - Aperture still recognises the camera and if it's supported, then it uses the camera specific conversion rather than the default DNG 2 conversion.

    I know what it's like, you use a camera for a year or so, then, 6 years later you want to look at the files again you may find that your converter of choice no longer supports them. At least, that's my logic.

    Just this guy you know

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    Re: Converting to dng

    As yet the DNG format is far from having become the universal format that Adobe wishes it to be. Once it or something else does it would only take a couple of days to convert all your files to it.

    That said I do convert to DNG for one reason only. You need a DNG to embed a custom colour profile in ACR/LR. I don't like DNG for quite a few reasons but having the location specific profiles that I make during a wedding embedded is worth the hassle for me.
    I am not a painter, nor an artist. Therefore I can see straight, and that may be my undoing. - Alfred Stieglitz

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    Senior Member Robert Campbell's Avatar
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    Re: Converting to dng

    I'm struggling a bit to understand where dng conversion starts and ends, and where ACR [or any other program] continues from. As I understand, any raw image has to be 'converted' -- in the sense of demosaicing -- to be visible in your pp program. So, if I convert .orf or .cr2 to .dng and then view in Lightroom, the image has undergone two conversions -- or have I got it all wrong?

    And if the demosaicing requires a specific profile, then presumably so does the dng converter -- hence the need to update it regularly, as new cameras appear.

    There's been some talk here about the abilities of various demosaicing programs to render better than others, or get out greater detail, or more accurate colours; yet I'm not sure how much of the improvement is real and how much is artefactual -- there doesn't seem to be any benchmark available to test various algorithms against. Some of this seems to assume either that all Bayer grids, no matter what the camera, have identical colour characteristics -- not just rgb, but identical rgbs -- or that it's possible to calibrate the Bayer grid for any particular camera model.

    If there are several potential variables in any raw file before demosaicing begins, does not a conversion to dng add to the complexity, and thus to the potential for error -- 'wrong' colours, jaggies etc?
    Sláinte

    Robert.

  6. #6
    hardloaf
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    Re: Converting to dng

    Whatever Adobe propaganda and their "victims" say just make sure that under no circumstances you delete or loose your original Raws from camera.
    Raws are actual Originals and results of Raw->DNG conversion are only inexact replicas. If you need DNG for some reason - fine as long as you have separate and multiple backups of your original Raws, because everything is restorable and reversible as long as you have your Originals.

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    Subscriber Member Jonathon Delacour's Avatar
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    To DNG or not to DNG?

    I've been following with interest the threads on using Lightroom together with Capture One (or another raw converter). Though I'd already been out a few times with Raw Developer, some friends suggested I'd find Capture One more attractive and even organized a date for me with C1. Unfortunately we didn't hit it off. Then Doug Peterson suggested I try to get back together with Raw Developer, saying that RD "manages to get better results (in pure IQ terms) than LR and is on par with C1 (sometimes better)". He was right -- it was love at second sight.

    So now my workflow is:
    * Photo Mechanic for keywords and rating which produces XMP sidecar files to accompany the original NEFs
    * Photo Mechanic to copy selects (one or more stars) into a Lightroom watched folder which automatically populates a Selects catalog containing the NEF+XMP files
    * Use Raw Developer to convert two (or more) star images to 16-bit TIFF files, saving these to the LR watched folder so that they wind up alongside the original NEF files
    * Additional PP either within LR or in CS4 (using the Nik plugins: Dfine, Sharpener Pro, Viveza)
    * LR for printing or web galleries

    In any case, having settled on a PM+LR+RD workflow, I was intrigued by one statement in Michael Reichmann's LR+C1 article:
    The major steps which I take in Capture One are to choose the appropriate camera profile, do a white balance, and then set black point and white point. These are the critical steps that need to be done in raw mode. I then export the file to Lightroom for further processing. I send the file as a 16 bit TIFF. DNG would be preferable, but the DNG export from C1 doesn't include any of the process settings, and one would thus lose the advantage of C1 matrix decoding.
    I am curious as to why he regards DNG as preferable to a 16-bit TIFF.

    Is it for archival reasons, because he believes the DNG format offers greater longevity than the RAW files he gets from his Phase and other cameras?

    Or is it because he believes that programs such as Lightroom have "essentially rendered Photoshop redundant for maybe 90% of the needs of most photographers. Many, myself included, now rarely use Photoshop except for a few specialized tasks"?

    This latter statement implies that -- apart from setting WB and black & white points in C1 -- he does all of his other adjustments in LR. Which means that he doesn't use any plugins at all since, even if you want to use (for example) the LR versions of the Dfine or Sharpener Pro plugins, LR creates a TIFF anyway (because your only option with the original RAW file or a DNG is to "Edit a Copy with Lightroom Adjustments").

    I'd be grateful if any forum members could point out if I'm missing something and/or explain the benefit(s) of converting camera original RAW files to DNG. As a Ricoh GRD user, I'm aware that certain cameras (Leica, Pentax, etc) use the DNG format for their RAW files.

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