March 06, 2007

DNG notes: Compatibility, Color, Hasselblad

A reader named Trace pointed out a discussion happening on the Inside Aperture blog, where there’s been some confusion about the DNG format.  Specifically, there’s been concern that if Adobe were to drop support for conveting from a particular format to DNG, those files would become incompatible with DNG-reading software.  Not to worry:

  • Right now photographers who want to use DNG mostly rely on Adobe software to do the conversion, but that’s not a requirement: the format is publicly documented, and Adobe provides open-source code for implementing DNG reading and writing (via the free DNG SDK).
  • There’s no relationship between the DNG Converter being able to convert a file to DNG, and DNG-reading software’s ability to read DNGs from that camera.  Even if Adobe were to stop supporting conversion from a particular format (something that seems unlikely, but which is possible), DNGs made from that format would remain perfectly readable by DNG-aware apps.
  • It’s true that the DNG Converter does need to be updated for new proprietary raw file formats. That’s the benefit that Adobe is providing: the translation of an unknown to a defined standard. And beyond the conversion experience, ask any photographer using a Leica M8 or Pentax K10D how much they appreciate instant support from the moment their first raw file is captured.
  • I’ve heard from certain camps that DNG is a bit of an empty promise, that these companies really have to do custom work for each camera & that they therefore can’t support DNGs made from cams they don’t support.  If that’s the case, why are DNGs compatible with Camera Raw in Photoshop CS1, which was last updated some two years ago?  It may be that a developer will want to do custom work for a camera, even if images from that camera are in DNG format, but doing so isn’t a requirement. [Update: See the comments on this story for more info on these points.]

At the end of the day, your photos are your photos, and you shouldn’t be beholden to Adobe or to any other company to read them.  Ultimately Adobe would like to turn stewardship of the format over to a standards body, but we’ve wanted to let it build momentum first.

While I’ve got your ear on the subject of DNG, here’s a bit more that may be of interest:

  • Lightroom and Camera Raw support the
    Hasselblad H2D, but the H3D raw file is 3FR, not DNG.  Why is that, and what does it mean?  In short, before handing off data to raw conversion/workflow software, Hasselblad wants to do additional custom  processing that isn’t practical to do in-camera.  According to the Hasselblad site,


    "3FR files can be converted into Adobe’s raw image format DNG (‘Digital NeGative’), bringing this new technology standard to the professional photographer for the first time. In order to optimize the colors of the DNG file format, conversion from the 3FR must take place through FlexColor. The DNG file format enables raw, compressed image files to be opened directly in Adobe Photoshop. Hasselblad image files carry a full set of metadata, including capture conditions, keywords and copyright, facilitating workflow with image asset management solutions."

  • Carl Weese wrote a piece called "There’s DNG—And Then There’s DNG," in which he mentions that his white balance settings changed after he updated to Camera Raw 3.7.  Thomas Knoll notes that to get the previous appearance, it’s possible to choose that option in the Camera Calibration popup menu.  (I don’t have any of these files on hand, so I haven’t tried this myself.)
Posted by John Nack at 11:24 AM on March 06, 2007

Comments

  • Rory — 9:13 PM on March 06, 2007

    Thanks for the DNG update John and thanks to Adobe for DNG. I wonder how long it will take for the Canon’s and Nikon’s to cave and accept that a standard is a no brainer and good for business.

  • Barry Pearson — 2:27 AM on March 07, 2007

    The question about Canon & Nikon is a good one, although I don’t think the word “cave” is helpful! (After all, both of them based their formats on the ISO standard raw file format – ISO 12234-2, TIFF/EP – just as Adobe did with DNG).
    Nikon is investing a lot in NEF, and NX can use NEFs in similar ways to how Adobe products can use DNGs – certainly holding editing settings, but I believe supporting JPEG-originals too. I suspect Nikon will not switch to DNG for years, if ever. I think Canon has less invested in the capability of CR2, but shows no public signs of switching their in-camera use.
    In-camera support of DNG is one of the least important aspects of the industry transition to DNG. After all, most people using and writing about DNG use Canons or Nikons, and most DNG images in the world started as NEFs or CR2s. I now have a camera that supports both PEF and DNG, yet set it to PEF, even though I am one of the most enthusiastic people around for DNG and have used it for years. My camera doesn’t compress DNGs, my Epson P2000 doesn’t show DNG thumbnails, and I convert to DNG while ingesting my raw files, so it just isn’t useful to use DNG in-camera now that Adobe supports the PEFs.
    This lesson is – it is far more important for software to support DNG than cameras, (although the latter is desirable too). That is how Pentax started with DNG – by providing free software to convert all PEFs to DNG even for historical cameras. I would like to see all camera manufacturers at least providing their own DNG converters, either to enable users to process their raw files with minimum delay when the camera is launched, but also as an archiving feature. I think that is likely to be Canon’s first step. The rest can follow gradually.
    I am more concerned about Bibble, Capture One, and camera manufacturers’ raw converters not accepting DNG. (Capture One has intentions this year; the latest Pentax software can read DNGs as well as write them, for DNGs written by Pantax products). And concerned about the limited DNG implementations of Aperture, ACDSee, and perhaps other major products. Each one of these inhibits a proportion of photographers.

  • Trace — 7:29 AM on March 07, 2007

    Hey John,
    Thanks for checking out (and linking to) the Aperture discussion.
    I may be misunderstanding your second point : “There’s no relationship between the DNG Converter being able to convert a file to DNG, and DNG-reading software’s ability to read DNGs from that camera.”
    I’ve made DNGs from a Canon 30D, and my point and shoot vacation camera, a Canon Powershot S50 (both supported by Adobe). The 30D DNG imports fine into Aperture (Apple supported camera), whilst the S50 DNG shows a place holder with the “Unsupported image format” designation.
    As the S50 is an admitted “amateur, point-and-shoot, FUN” camera, I’m not too disappointed that a professionally designed app does not support it. Unless I’m wrong, this points to the fact that every 3rd party RAW conversion software (ACR/Lightroom included) has their own “secret sauce” way of interpreting a camera makers RAW coding, and applies very different basic settings when opening RAW files. No two RAW converters interpret a file the same. Given this, and that DNG is really “another” RAW format, each software developer (Aperture, Capture NX, Bibble iView…etc.,) STILL needs to open it up and apply it’s “interpretation” to the camera’s unique way of capturing RAW. This is what “support” means.
    [So, let's get down to brass tacks. Apple *could* open any DNG files, but they *choose* to support only those that come from cameras they have already supported. That's their call, but it's not a comment on DNG. The simple counter-example is that you can make a DNG from a photo taken by a new D40, then open & manipulate it in Photoshop CS1--i.e., raw-processing software that hasn't been updated in two years. If it were true that only images from already-supported cameras could be read, then DNGs made from new cameras wouldn't work in older copies of Photoshop. It also wouldn't have been possible for Photoshop to support cameras like the K10D the moment they came out. The fact that those cameras shoot DNG means that they're immediately supported in CS1, 2, and 3.
    The Aperture team choose not to support camera models that they haven’t already profiled. That’s obviously up to them. But let's not get confused and equate their choice with a limitation of DNG. --J.]
    I haven’t used any RAW conversion software except ACR and now Aperture, but I believe each 3rd party RAW converter lists it’s supported cameras, meaning those engineers took apart that cameras settings for RAW and wrote code for it.
    So (to take Aperture as an example), even if Adobe provides Apple with an “open standard” code of how to read the DNG of my Powershot S50, it will be Adobe’s interpretation of the file, not Aperture’s unique interpretation based on original camera’s unique RAW code.
    [That's incorrect. There are two separate things: the raw data itself, and the rendering of that data (i.e. how it gets displayed). DNG addresses the former, converting the proprietary bits into a documented standard. According to Thomas Knoll, in most cases the actual raw data is bit-for-bit identical. The only part of an Adobe-made DNG file that’s Adobe’s interpretation is the embedded preview, which a tool like Aperture would ignore.
    DNG contains embedded color calibration information, so a reader does not need special knowledge about the camera to process it. This is how Adobe is able to process DNG files from cameras it has not seen before. Apple uses its own color calibration information, and they apparently did not write the code read the color calibration information in the DNG. Therefore they just refuse to read the file if they don’t know the model. Some other third party DNG readers do a much better job here. For example, the Silkypix raw converter also has it own per-model color calibration that is normally uses. However, if it sees a DNG file, it offers the user the choice: use the embedded color calibration, or use its own. This allows it to read DNG files from otherwise unsupported camera models, just like Adobe’s software can.
    The work of profiling a particular make of camera (e.g. determining that Camera X leans a little towards magenta, and that the highlights should be pulled in) is a separate matter. That's the part that's up to software vendors, whether the images are DNG or another format. --J.]
    DNG is still a “sticky wicket”, unless camera manufactures enable it natively, but all the Raw Converters will still need to figure out how to give it their special interpretation via camera support.
    [Hopefully my responses above are useful in untangling the two aspects of what it means to support a camera. --J.]

  • Trace — 5:59 PM on March 07, 2007

    John,
    Thanks for sticking with this. Not trying to goad you, really!
    [I know, and it's good to get the info out there. --J.]
    I understand we have DNG converters, and DNG “readers” (Aperture would be considered the later, although it could be a converter too if Apple chose, correct?).
    [Correct. Or Apple (or anyone else) could write a separate DNG converter. --J.]
    Good term you have.
    And as you say, only the DNG Converter(s) needs to be updated with new camera support, in order for it to create a DNG file in the first place. And a DNG “reader” (your example being the CS1 – version of ACR), has no need to ever be updated, it will always be able to read the file.
    [That's right. Now, it's possible that the DNG spec could be extended in the future in such a way that readers would need an update (e.g. it would support more advanced compression options). But DNGs written to the base-level spec (i.e. the one that exists today) would always be readable. --J.]
    Since ACR/DNG Converter are tied together now (they both are updated together, and offered as a joint download on Adobe’s site), and presumably Lightroom gets the same update at the same time, in order for any “reader” to be of any use depends on Adobe updating camera support for DNG Converter.
    [No. Again, other people can (and do) write software that writes DNGs. And even if Adobe's DNG Converter were the only game in town, photographers would be dependent on it *only* for converting from cameras that aren't already supported. The 150+ cams that are already supported would remain supported. --J.]
    Unless DNG converters can operate without need of “updates”, or camera models support it natively, creating DNGs in the first place is the weak link to adoption. In other words, “reading” DNGs in the future is not the problem, but “creating” them is if a camera is dropped from the support list in a newer version of DNG Converter, and one is still shooting with that camera. But that would never happen, aye?
    [Well, in the odd event that that happened, why wouldn't people just keep using an older version of the converter? Or use an alternate converter? I mean, one could string together enough "ifs" to make anything problematic, but it doesn't seem likely, nor does it change the fundamental offering of DNG: getting data into a format that's vendor-neutral, so that you can work with it in the future, using your tool(s) of choice. --J.]
    How about a symposium/roundtable discussion on the issues? Adobe, Apple, Cannon/Nikon/Olympus, etc., photographers and 3rd party software companies, and of course Thomas Knoll, to help educate us openly. All sides of the issues openly discussed by those “in the know”. A broadcast web event for Adobe? That would be fascinating!
    [Sure, that could be good. For now, though, there's this small matter of shipping CS3, plus a whole lot more that's clamoring for attention. --J.]
    Thanks again for listening John. Appreciate your input here
    ~Trace

  • Barry Pearson — 12:42 AM on March 08, 2007

    For Trace:
    DNG has far more support by other companies than many realise. About 140 companies have products that use DNG in some way. There are about 10 DNG Converters, most of them written by camera manufacturers or even “amateurs” wanting support for cameras that Adobe or others don’t directly support. Several cameras and digital backs use DNG as their native raw format.
    I have no connection with Adobe, other than to use some of their products. I have published a lot about DNG on my (non-commercial) website, and it may answer a number of your questions already:

    For interest, at PMA a year ago there WAS a discussion about “Going RAW – Is a Standard RAW Image Format Possible”, see link below. I think a problem would be that camera manufacturers and software developers who don’t currently support it might be wary about the consequences of attending a discussion specifically about DNG. They might be seen to be endorsing it when they don’t, or be afraid of being thought to be negative. Even Pentax, Hasselblad-Imacon, Leica, etc, may not want to be exposed to questions about their future plans.
    http://www.i3a.org/virtual/eye_on_imaging_v3_n2.html
    I think the question “if Adobe went bust, how would existing camera support be carried forward to new platforms, such as whatever follows Vista?” is interesting, even though rather extreme. Would Adobe release the source code to make it easy for others to carry support forward? (I thought I read somewhere about some such arrangement for Adobe products in general?)
    [Excellent info, Barry--thanks. --J.]

  • Trace — 3:47 PM on March 08, 2007

    Thanks Barry & John. Appreciate your comments. I wasn’t implying that Adobe could go bust, simply that when/if they turned the format’s management over to another group (ISO perhaps?), a choice could be made to discontinue support for any camera by that body. Adobe could also decide (internally), to drop support for any camera if, for example it’s deemed “too old” to matter, and/or that there are too many lines of code (and every new camera supported adds code), and some needs to be dropped. All likely scenarios.
    Heck, we never thought there would be a day without Kodachrome, or Tri-X film, and the chemistry and papers to go with them, but those days are rapidly upon us. Who thought Agfa would be out of the market? Who ever thought RSP and iView would be swallowed up? It’s not impossible that Adobe could be folded into another company…interesting times, indeed!
    Mainly, I’m saying there are no guarantees, and no company can claim true “archivability” on anything they create.
    [All I can is this: the full DNG specs are out there, and Adobe has provided open-source code for reading and writing DNG files. That's the best way to future-proof data we can think of. You're not beholden to Adobe. I don't know what else to say. --J.]
    Currently, the Jpeg file format is the only popular, “company neutral” image format (save maybe PNG too); with PSD, TIFF and now DNG all under the ownership of Adobe. I think if you want DNG to be truly more widely adopted, now is the time to give it to a neutral body. (though I know Adobe’s stated reason not to at this time).
    This link gives some interesting talk from various segments on the subject: http://news.com.com/Adobe+taps+the+power+of+negative+thinking/2100-1041_3-6136875.html?tag=nefd.lede
    Guess the question is which comes first…industry support or consumer support? I do hope DNG will be able to reach it’s true potential, but as a photographer, I am wary…
    ~Trace

  • Trace — 4:33 PM on March 08, 2007

    John,
    One last thing (promise): I tested opening a DNG that was created with the Adobe DNG Converter (3.7), and tried to open it both in Photoshop 7.0 and CS (version 8, I assume this is what you meant when you said DNGs were backward compatible with CS1). Both times I got a “Could not complete your request because it is not the right kind of document”. To be fair, you never said anything about Photoshop 7.0, but I was curious. Guess DNG isn’t happy with me…;~)
    ~Trace
    [Good questions. Thomas K. says, "If you have Camera Raw 2.4 installed in CS1, this should work for all current camera models supported by the DNG Converter. The single exception that I'm aware of the unofficially supported Fuji S5Pro, which only works if you use the 'Linear' option in the DNG Converter." --J.]

  • Vojtech Tryhuk — 12:39 AM on March 09, 2007

    I don’t understand, why so many people complain on TIFF and DNG being under the ownership of Adobe. I never had a single problem with that, on the contrary when I need some specification from some “neutral body”, it isn’t usually free and it doesn’t adapt itself to the current needs of industry fast enough…
    I appreciate all the effort that Adobe put into DNG, although I don’t like the idea of non-raw data in DNG, I would prefer if it would have at least a different extension. This way it might cause same confusion as TIFF does – that people just won’t get it, why the software opens one file and other not.
    Etc

  • jon Moe — 9:12 AM on August 11, 2008

    Why doesn’t adobe support Hasselblad 3fr files?

  • photo retouching — 12:11 AM on April 23, 2009

    I suppose we are still in the “Blu Ray” vs the competition stage of the debate. It is only a matter of time before the others realise the adobe dng is the industry standard.

  • Luke Mendes — 5:26 AM on May 22, 2009

    Hi I need to convert some shots taken on sony Alfa 24 MP camera. The files are in CR2. I need to work on them on my Photoshop CS. Can anyone help..Luke

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