Are you converting your RAW images to DNG?

Discussion in 'Digital Photography' started by JC Dill, Oct 8, 2006.

  1. [snip]

    No. (I think there are at least 3 books that discuss the use of DNG,
    written by photographers with far more expertise and experience about
    raw shooting than me).

    A common raw file format is important for the future health of top end
    digital photography. DNG is the only contender, and is a
    well-engineered one.

    I read the specification and other information about it before I
    started using it (exactly) 2 years ago. This combination of technical
    knowledge and personal experience enabled my to spot misunderstandings
    and misrepresentations in various forums at least a year and a half
    ago, and I responded to them. (I don't care what opinions people have,
    nor whether they use DNG, but I do care about misinformation being

    When I realised that similar misinformation would continue to appear
    for a long time, I captured my responses on web pages to reduce typing
    and provide much more background information for people who wanted it.
    When I respond with a link within one of my web pages, that is a clue
    that the statement I am responding to has appeared a number of times

    I'm wondering whether to turn those pages into the basis of an FAQ. But
    a difference compared with many other topics that have an FAQ is that
    many people don't simply have queries about DNG, they have apparent
    hostility. This is a puzzle - why should a file format have this
    effect? TIFF doesn't appear to, yet it too is owned by Adobe.

    This attitude is somewhat camera-manufacturer-dependent. On average,
    Nikon forums tend to be more anti-DNG than Canon forums, although it
    can appear there too. At the other end of the scale, Pentax forums are
    likely to send letters to Pentax asking for DNG support. I can
    understand that Nikon and Canon users would say "DNG isn't important to
    me", in other words "not pro-DNG". But they sometimes they take a more
    aggressive "anti-DNG" stance. Curious.
    Barry Pearson, Oct 11, 2006
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  2. JC Dill

    Scott W Guest

    I played with it some when it first came out but at the moment it does
    not really offer me anything. In the future I might converter my raw
    files to DNG for archiving but to me it makes sense doing this a few
    years down the road since the DNG format might change and I would hate
    to have to convert the files twice.

    I was greatly disappointed about one part of DNG and that was that
    programs that can read in a DNG file and do not necessarily deal with
    DNG files made from every raw format. A case in point if the raw files
    from my Sony F828, not a lot of support for this raw format but I can
    convert it to DNG, the only problem is if the raw converter does not
    handle F828 raw files then it also fails to handle DNG files made from
    the F828 raw file.

    Since I am not about to delete my original raw files I would be
    doubling the storage space for little benefit.

    Scott W, Oct 11, 2006
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  3. JC Dill

    JC Dill Guest

    I'm not looking for "a DNG forum", I'm looking for those forums where
    regular photographers meet and discuss dozens of topics, where DNG is
    *also* discussed. This is one such forum, but DNG discussions have
    been very sparse - that tends to indicate that DNG is not widely used.
    A DNG-specific forum won't have any value in determining how widely
    used DNG is - everyone in a DNG-specific forum will likely be using
    (or considering using) DNG, right?

    I took your first search query and modified it to exclude "adobe"
    since so many of the hits from that query were links to Adobe's DNG
    forum. Then I found this interesting thread:


    And that, in a nutshell, is why I think that DNG isn't yet ready for
    prime time. IView is one of the programs you list as fully supporting
    DNG, but IView doesn't *really* support DNG in that changes made to
    the DNG file outside of IView aren't shown inside IView unless
    (apparently) the user "rebuilds the thumbnails". Why should one need
    to "rebuild thumbnails" when the file format HAS thumbnails in it?
    Software that *fully* supports this file format should automatically
    use the embedded thumbnail.

    JC Dill, Oct 11, 2006
  4. JC Dill

    John Bean Guest

    Because MediaPro is flexible. You can have it build its own
    thumbs or use the embedded ones, ditto for the previews,
    This gives the user to control the size/quality of thumbs
    and previews independently from those in the raw file (DNG
    or otherwise). This allows you to change the settings to
    best reflect the content of the file(s) you are importing on
    a file-by-file basis if need be, without affecting the
    settings of files already imported. The thumbs it builds are
    cached in it's database along with other data and are
    available even if the file(s) they represent are not
    available online.

    So if you want to change the settings of an *already
    imported* file (or files) you select it and hit Ctrl-B and
    it rebuilds the thumb(s) from scratch with your new

    For DNG files I tell MediaPro to build its own thumbs (I
    like them bigger than the default) but use the embedded
    preview image from the DNG. Works perfectly.
    John Bean, Oct 11, 2006
  5. Searching* for DNG in the title only gave 31 articles, but
    they tend to be people deliberately discussing DNG as a chosen topic:*&as_usubject=DNG

    Searching* for DNG in the body gave 436 articles, suggesting
    that most of the mention of DNG is fairly casual, not within an
    explicit discussion of DNG:*&as_q=DNG

    My conclusion from those articles is different from yours. I believe
    many people using DNG simply think it ordinary, not newsworthy.

    Here is a search that yields over 9700 results in 2 years in one web
    site, over 13 per day:
    Picking one thread out of a large number over the last 2 years, talking
    about one discussion of one product out of more than 140, and then
    coming to such a conclusion, (perhaps out of a misunderstanding of the
    product, judging by John's response), appears to me a desperate attempt
    to find some way of rejecting DNG!

    As I've said, I don't care whether particular people use DNG. If you
    personally don't want to use DNG, then don't! You don't need to justify
    it to anyone, certainly not me. What I care about is misrepresentation,
    because that might mislead others.

    I suspect that some of the complications in this thread arise because
    people tie their own personal decisions to inaccurate statements about
    DNG. When someone like myself refutes those latter statements, it may
    appear (incorrectly) to be an attack on that personal decision, or
    evangelising to persuade that person to change the decision.

    (For example, if someone says "I don't use DNG because its only benefit
    is that files are smaller", then anyone pointing out further benefits
    might appear to be trying to undermine that decision not to use DNG,
    whereas they are simply providing a correction).

    Perhaps this accounts for the apparent hostility (here and elsewhere)
    towards DNG. This hostility is puzzling for a file format
    specification! Statements like the following, (not made by you), are
    simply irrational rants: "By its very nature, DNG is limited to
    hobbyist, experimenters, and "open source" advocates that have an ax to
    grind with Adobe". (I didn't respond to that statement because no-one
    is likely to be fooled by it).
    Barry Pearson, Oct 11, 2006
  6. You illustrate an important point, although it is not actually a
    criticism of DNG. (It is about the restricted and deficient
    imlementations of DNG, which should not be blamed on DNG itself).

    Your example is a source of frustration for some people whose cameras
    have such less-common sensor configurations. They wonder why a "common
    (or universal) raw file format" like DNG doesn't solve this problem.
    But NO true raw file format can solve this problem! The photographer's
    use of "raw" postpones the processing of the raw image data data to the
    raw converter, so that is where the necessary code must exist. Once
    that raw image data is in the memory of the raw converter, it doesn't
    make a difference to the code whether it came from a DNG file or a
    native raw file.

    DNG offers a solution to this problem too - "Linear DNG". This is a
    variant of DNG containing image data that is no longer raw. Raw
    converters need extra code to handle Linear DNG, but it then enables
    them to perform many of their tasks even in many cases where they don't
    otherwise support the sensor configuration concerned.

    But that can also fail. For example Silkypix can handle Linear DNG, but
    only for 3-colour sensors! Not for the F828. They need extra code for
    that, and presumably haven't thought it worthwhile yet to develop that
    Anyone who only holds one copy of their source material runs a risk.
    Some people retain "original raws" plus "DNGs", giving them both
    flexibility and extra resilience.
    Barry Pearson, Oct 11, 2006
  7. JC Dill

    prep Guest

    That will depend on the laws in the specific instance. How ever, in WA
    courts if you want to introduce a photo, you MUST produce the
    negative. That is the LAW, specifically the Evidence Act. Further, you
    must produce the ORIGINAL evidence, so if we hand wave the negative
    part, a DNG produced from a CD2 or NEF woud not pass muster, and if
    you had deleted the original as part of the conversion you would have
    your case thrown out and you may even be charged for destroying

    Paul Repacholi 1 Crescent Rd.,
    +61 (08) 9257-1001 Kalamunda.
    West Australia 6076
    comp.os.vms,- The Older, Grumpier Slashdot
    Raw, Cooked or Well-done, it's all half baked.
    EPIC, The Architecture of the future, always has been, always will be.
    prep, Oct 13, 2006
  8. JC Dill

    prep Guest

    For many years I used Display Postscript. It worked well, and was
    robust across macines and displays. Then Adobe wanted pdf to ne the
    new wonderchild, and ripped out all the DP SDK licences so users where
    left stranded... Note that DP was also `well engineered'.

    Paul Repacholi 1 Crescent Rd.,
    +61 (08) 9257-1001 Kalamunda.
    West Australia 6076
    comp.os.vms,- The Older, Grumpier Slashdot
    Raw, Cooked or Well-done, it's all half baked.
    EPIC, The Architecture of the future, always has been, always will be.
    prep, Oct 13, 2006
  9. On Oct 13, 8:44 pm, wrote:
    New technology requires law to be re-examined and sometimes
    reformulated. What you say raises questions. For example, would someone
    who shoots JPEG be able to introduce a photo, even though they (or
    rather their camera) had destroyed the original raw image data? What
    about someone who uses asset management tools to put metadata into
    their raw files, perhaps as part of the ingestment process? Obviously
    people supply copies of the image data, not the in-camera original. Is
    it a copy of the "raw image data" or the "raw file" that matters?

    While interesting, this has little impact on the take-up of DNG. Most
    people using it aren't concerned with such laws. And at least 2 copies
    of the raw image data are needed for safety, so some DNG users keep an
    archive of the original raws while working with the DNGs. (Surely
    anyone whose job involved court work like this would keep a pristine
    archive of the originals well away from their working versions, "just
    in case"?)

    The long term answer for these cases will be DNG in-camera. Until then,
    people in some specialised jobs will find blockers to the use of DNG.
    Barry Pearson, Oct 14, 2006
  10. On Oct 13, 8:50 pm, wrote:
    It would be interesting to see how Adobe could rip out all the DNG SDK
    licences, given that it has been openly published without time limit.
    (The DNG SDK is freely-available source code, not something you have to
    jump through hoops to get).

    But the DNG SDK isn't necessary to develop products using DNG, of
    course. It was only released in April 2006, by which time probably more
    than 100 non-Adobe products supported DNG. The key to the rapid
    development of DNG support was the freely-available specification,
    togather with an openly published license to use it.
    Barry Pearson, Oct 14, 2006
  11. Of course, this leads one to ask, "Why go through all the extra steps of
    converting to a dead and useless format when it's not even required and
    reduces productivity?" Time is money and most agencies don't have the
    resources for their employees to be hobby crafting when core work issues
    need to be addressed.
    Now you're getting it. Most people that use it are not professionals or
    have way too much time on their hands to burn.
    Unfortunately, there are no pro cameras that use this format.

    =?iso-8859-1?Q?Rita_=C4_Berkowitz?=, Oct 14, 2006
  12. Nobody has to rip anything; they just have to stop supporting it. This
    especially sucks if it is embedded in the core of the software/firmware
    needed to operate a particular device. Even the smartest might not be able
    to "hack" their way into fixing this problem.
    Yeah, like the same way that open source software was predicted to bring
    Microsoft to their knees. Sorry, it aint going to happen.

    =?iso-8859-1?Q?Rita_=C4_Berkowitz?=, Oct 14, 2006
  13. Ah, forgot about this little PostScript gem. It seems the consumer has a
    very short memory. A lot of companies made big bucks from selling this
    dead-ended technology. I remember some of the PostScript modules in
    printers used to fetch good money. It was more economical throwing the
    printer away and selling the PS module. I see the same thing happening with
    DNG. You'll see a small segment buy into the pipedream only to fall on
    their ass later on down the road.

    =?iso-8859-1?Q?Rita_=C4_Berkowitz?=, Oct 14, 2006
  14. JC Dill

    Paul Rubin Guest

    Where can I download it from, other than an Adobe site? I see this
    URL at Adobe:

    but it wants me to agree to a license before I can download.
    Paul Rubin, Oct 14, 2006
  15. JC Dill

    Joan Guest

    Joan, Oct 14, 2006
  16. JC Dill

    Paul Rubin Guest

    If the only way I can get the software is by agreeing to a license and
    then downloading from Adobe, then the software becomes inaccessible if
    Adobe decides to stop offering it. Barry said "[t]he DNG SDK is
    freely-available source code, not something you have to jump through
    hoops to get." "Freely available" to me means anyone who wants to
    offer it for download can do so. That means it stays available even
    if Adobe gets tired of it. "Not have to jump through hoops" means no
    need to agree to a license just to download or use it. That makes it
    possible to include it in large software collections (e.g. Linux
    distros) without the user having to agree to N different licenses.

    So I'm asking for a non-Adobe URL where I can download it without
    having to agree to a license. If no such URL exists, Barry's
    description appears to be inaccurate.
    Paul Rubin, Oct 14, 2006
  17. [snip]

    How can Adobe remove the DNG SDK from your PC or your own backups?

    Now that this license has been published (and copied), how can Adobe
    stop you using the DNG SDK in future?

    Once you've downloaded it, the DNG SDK will be freely-available to you
    for as long as you want. And at the moment it is freely-available to
    anyone, as they can verify.

    Or, of course, you can develop and supply products that exploit DNG
    without using the DNG SDK. Nearly all existing products were produced
    that way.
    Barry Pearson, Oct 14, 2006
  18. JC Dill

    Paul Rubin Guest

    Having it on my own PC or backups is a far cry from "freely available"
    which means I can get it from anywhere. "Freely available" is what
    creates the possibility of a worldwide, distributed developer
    community. GIMP 2.0 could never have been written, if everyone
    distributing GIMP 1.0 had been required to stop, leaving copies only
    on individual user's computers. The code has to be able to continue
    to be distributed and improved, even after the original developer has
    moved on to other things.
    I can't parse this. I don't understand the relevance of copying a
    Paul Rubin, Oct 14, 2006
  19. There isn't just one source of DNG technology. Many companies have
    developed technology to read and/or write DNG files. dcraw.c is open
    source code that can read and render DNG. elphel_dng.c is open source
    code for writing DNG.

    It is other formats that are likely to be more problematic. Where is
    the publication of the NEF or CR2 specification? Where is the NEF or
    CR2 SDK freely-available from? Where are the published royalty-free
    licenses for anyone to exploit DNG and/or the DNG SDK? It is important
    to judge any alternative to DNG by the same criteria used to judge DNG

    There are aspects where DNG is uncontroversially better than
    alternative formats. Whatever views about whether DNG is the right
    answer, it is obvious for reasons such as the following that it is a
    better answer than the current alternatives:

    1. It is openly documented.

    2. It is supported by a freely-available optional source-code-based

    3. There are public royalty-free licenses for anyone to use the
    specification and the SDK and to supply products based on these.

    4. DNG is based on the principle of "no unnecessary differences"
    between manufacturers and models.

    5. DNG files contain parameters describing camera and sensor

    6. DNG has a version scheme that enables the DNG specification, DNG
    readers, and DNG writers, to evolve at their own paces, under control.
    Barry Pearson, Oct 14, 2006
  20. You have produce your own definition, which I don't accept, to make a
    case that it isn't freely-available. What is your point? You or anyone
    on the planet can get hold of the code and develop and supply products
    that exploit that code!
    There is nothing to prevent YOU developing open source technology for
    exploiting DNG. Dave Coffin has done so! No one forces you to use the
    DNG SDK, if you don't like the license agreement. Why not take dcraw.c
    and elphel_dng.c and start from there? Or just start from the
    openly-published royalty-free specification, and use whatever
    freely-available code you can find that handles TIFF format, etc?

    Your quibbles are self-imposed blocks - people who developed products
    that support DNG didn't erect such barriers!
    Which companies' SDKs had to be freely-available before GIMP could be
    developed? What (if anything) stopped GIMP being developed without
    relying on any companies' SDKs?

    To make sure it can be produced as evidence if ever Adobe withdraws it,
    (which they won't).
    Barry Pearson, Oct 14, 2006
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