Raw vs. DNG

Discussion in 'Image Processing' started by TwoWheels, Jul 23, 2015.

  1. TwoWheels

    TwoWheels Mu-43 Top Veteran

    May 28, 2014
    British Columbia
    Since starting to use Lightroom a number of years ago, I have just imported my Nikon/Canon/Olympus/Panasonic raw files into Lightroom as DNG and then deleted the raw files. The first time I thought about whether I should do that was when I first took HDR's. I kept the raw files in case I ever wanted to re-process them since I was importing the raw files directly into Photomatix. But my current understanding is that DNG is a lossless format. And since it's likely to be a viable format as long as any of the proprietary formats, it seems to me there may not be any compelling reason to save any raw files in addition to the DNG files.

    I haven't been able to find a lot of information about this. Am I thinking correctly that the DNG files are essentially the same as the RAW files in terms of the data they contain and the ability to process them? I don't want to sacrifice any future processing ability (as software improves which I'm sure it will) by keeping DNG instead of the original raw files. I also don't want to needlessly keep both. What do you do and what's your thinking behind it?
  2. barry13

    barry13 Super Moderator; Photon Wrangler Subscribing Member

    Mar 7, 2014
    Southern California
    I saw a post or blog last week by a user who was irate because he just switched off of Lightroom and found the dng files didn't keep enough info for the new app to detect the camera and apply the correct color profile automatically.

    • Useful Useful x 1
  3. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Was it this one?

    I've never used DNG myself, but this article is the first thing I thought of when I saw this post.
  4. barry13

    barry13 Super Moderator; Photon Wrangler Subscribing Member

    Mar 7, 2014
    Southern California
    Yes, that was it.

  5. tkbslc

    tkbslc Mu-43 Legend

    I guess I'd ask why wast CPU cycles converting to DNG? Lightroom can handle the native RAW files already.

    I think having both DNG and RAW is a waste, but I solve that by not convertnig to DNG.
  6. chrisada

    chrisada Mu-43 Regular

    Mar 4, 2014
    One often-cited reason is long term compatibility. Not all camera makers today will still be in business 10-15 years from now, so their proprietary formats may not be supported by the software we have then. DNG being a common standard has a higher chance here.
  7. tkbslc

    tkbslc Mu-43 Legend

    I think you'd get a pretty good warning for that unlikely scenario and have time to convert later. I mean, LR6 still supports Kodak DSLR and Minolta DSLR files. It's been over 10 years for both of them.
    • Agree Agree x 2
  8. Rudy

    Rudy Mu-43 Top Veteran

    Jan 24, 2013
    Oakland, CA
    Even if it comes to the point where a particular raw file type is no longer supported by newer software, you can still use the older version and bulk convert the files at that time...
    • Agree Agree x 1
  9. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    I would guess that there are more raw processors that don't like the DNG that comes from an Adobe DNG conversion process, than raw processors that don't like a particular camera's raw file.
  10. Dragos101

    Dragos101 Mu-43 Regular

    May 1, 2015
    Bucharest, Romania
    Exactly, DNG was an attempt made by Adobe to standardize the files and also strengthen their position as a de facto developer, or a market leader. It didn't succeed, so your best bet for maximum future compatibility is to stay with the original raw files.
    • Like Like x 1
  11. edmsnap

    edmsnap Mu-43 Veteran

    Dec 20, 2011
    Edmonton, Alberta
    Compuserve ceased being a company of any significance in the mid-90s and has been out of business for years. You'd be hard-pressed to find a graphics program that can't still read a GIF. I'm not sure why a company's disappearance would mean that their format, used for millions of pictures around the world for years, would be written out of people's software code. If file formats were that fleeting, then DNG would be just as likely to fade away and be forgotten.
  12. fredlong

    fredlong Just this guy...

    Apr 18, 2011
    Massachusetts USA
    The most future-proof solution would probably be to convert to 16 bit tiff files and save in one of the lossless compression formats and archive. You lose the camera specific data stored with the raw file, but 16 bits/channel will keep all the exposure data.

  13. SojiOkita

    SojiOkita Mu-43 All-Pro

    Feb 23, 2014
    It's a little more complicated.
    A DNG keeps all the RAW information, and most of the metadata (and for sure, the type of camera & lens).
    The only thing that could be missing is some makernote info that are useful only to the manufacturer's raw converter.
    There are tons of way to store some useful information in the DNG, as a DCP color profile, lens corrections etc... etc...

    One example : with an E-M10 RAW, Capture One doesn't take into account the manufacturer's distorsion correction.
    With a RAW converted to DNG, the manufacturer's distorsion correction is converted in the DNG standard, and Capture One is able to take it into account.

    My point of view: DNG is a great format, especially when it is native (I can make DNG with my phone - Nexus 5 - and post-process them in any RAW converter. The results are way better than the JPEGs).
    But DNG is an Adobe format. It is documented and can be used without paying anything to Adobe, but only Adobe decides how it is made and how it evolves.
    That makes little reason for anyone except Adobe to use this format.

    And there is currently almsot no reason to convert a RAW file into a DNG.
    Most of non-Adobe software have a inperfect way to read the DNG file and if you use, for example, Capture One, you'd better use it with the RAW that with the DNG if you want to have a correct color rendtion.

    I really don't know why Capture One - for example - can't apply the same color profile for a DNG as with a RAW file... but that is a fact. You won't get correct colors with a converted DNG file and C1.

    I never understood the reason of this...
    You have to compare:
    - How many old RAW files are not supported by recent software? -> NONE
    - How many RAW converter are not supporting / have a bad support of DNG files? -> almost every non-Adobe software.

    If ever you RAW file is not supported by some software in the future, you would still be able to convert a RAW to DNG with Adobe DNG converter.
    (and hope to use Adobe software because all other software won't have a correct color profile to assign to the file).

    If DNG converter can't convert your file or doesn't exist anymore at the time, well that probably means that DNG is also dead.

    A RAW can be converted to a DNG. A DNG can't be converted back to a RAW.
    So if you have to keep only one of them, you better keep the RAW.

    I will add one example.
    I use Lightroom for all my photos.
    That means, a photo I took in 2005 with my Canon 350D (= Digital Rebel XT) is still stored as a RAW and interpreted "on the fly" by Lightroom.
    Because that's the way Lightroom works. You don't open a file, post-process it, export it and forget the RAW.
    The files are always interpreted as a RAW + parameters, so all the files that are in your library are RAWs.

    So if one day, Adobe decides not to support anymore the Canon 350D files, that means Lightroom library won't be able to show all my Canon 350D pictures.
    That would mean Lightroom will be useless for me and that I would go and buy a non-Adobe software instead.
    So that's something that they won't do, it would be really stupid from them.

    So in conclusion:
    - Adobe software will always support the old camera RAW files.
    - non Adobe software DNG support is not very good

    So what is the point of converting your RAW files into DNG for future compatibility?

    In theory, anyone can make a software that reads DNG files, including the color profile included in it.
    In reality, only Adobe makes such software...
    • Like Like x 1
    • Agree Agree x 1
  14. mcasan

    mcasan Mu-43 All-Pro

    Feb 26, 2014
    On the Lightroom forum and other sites I have never seen a panic message of folks wanting to convert native raw to DNG. On the other hand it is easy to find panic thread where folks converted native raw to DNG without embedding the native raw and threw away the original raw file. Then for some reason they want to retrieve the native raw from the DNG. That won't happen.

    I have found zero reason to spend time and effort using DNG. Disk drive space is dirt cheap. Use 6TB drives in RAID pairs for both library and backups.
  15. dwig

    dwig Mu-43 Top Veteran

    Jun 26, 2010
    Key West FL
    Personally, I find little reason to convert native RAW files to DNG on a general basis. There are a few reasons to consider, though:
    • as a way to shoehorn RAW files from a new camera into slightly older software that doesn't support the new camera's native RAW files
    • for situations like the Capture One issue SojiOkita mentioned in post #13, above
    • as a way around flawed support for the native RAW format of a supposedly supported camera model.
    This last issue is not likely to be present in the wild yet, but will likely happen as some time in the future. Testing newly compiled software it a laborious and time consuming chore. With RAW converters this is an every expanding chore if comprehensive testing is done on every "supported" RAW flavor. The day will come that some popular RAW converter acquires bugs in its support for some older RAW flavor that went untested in recent releases of the software. Converting to DNG, a RAW flavor that is more likely to be well tested than that of some 10 year old digital camera that didn't sell in high quantities, will be one possible way around the issues.

    • Like Like x 1
  16. SojiOkita

    SojiOkita Mu-43 All-Pro

    Feb 23, 2014
    Yes, but you also have to consider one thing.
    If a camera is not supported by some RAW software, that means the software did not made a color profile for it.
    So, the software can read the Adobe standard DCP profile that is included in the DNG (it seems that C1 can do it now), and also interpret it correctly (not the case for C1 imho).
    Or else... that means that the color rendition is totally random.

    Currently, it's the contrary. For example, both Capture One and Rawtherapee have an incorrect rendition of DNG files.
    (the color profile included can totally screw up the color balance... I don't understand why but both software do the same...)
  17. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    That's actually a criticism of Capture 1 and Rawtherapee. Can't they get it right? If they can't get that right, why should we be confident that they can get all the raw files right? We shouldn't. Beware, I say.
  18. TwoWheels

    TwoWheels Mu-43 Top Veteran

    May 28, 2014
    British Columbia
    Thanks for your input, everyone. Now that we've cleared that up.... :shakehead: :hmmm: :confused-53:

    So let me summarize what I think I read above and correct me if I'm wrong: 1) I can import as DNG and that will probably be fine as long as I stay with Lightroom for processing and maybe if I don't as there is some likelihood that DNG will be supported by other third party software. 2) I can import as native raw files and that will probably be fine as long as Lightroom supports that particular raw file format. 3) I can save my raw files separately then import as DNG (the belt and suspenders approach) and have all my bases covered--probably the safest approach. Is that about right?
  19. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    Yeah but just remind me why that is better than simply using your raws files?
  20. TwoWheels

    TwoWheels Mu-43 Top Veteran

    May 28, 2014
    British Columbia
    Assuming you're talking about #3, I think it's theoretically better because you would still have your original proprietary raw file along with a DNG file which presumably is more of an industry standard. That means ten or twenty years from now you have a DNG file that may still be supported/recognized by the latest and greatest new processing software unlike your proprietary raw file from a camera company that is bankrupt, merged or acquired and no longer exists. Alternatively, if you move away from Adobe sometime, you still have the original raw format if, for some reason, your new software doesn't play nicely with DNG files.

    I'm not saying I think it's necessary to have both formats, it's just my summary and interpretation of the responses above. It does seem like the most conservative approach for those concerned with the ability to reprocess their raw files over the very long-term.
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