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I'm aware of the difference between RAW and DNG file formats. The RAW format is proprietary to the camera manufacturer while DNG is an open standard. DNG files can be compressed without loss of detail, and can also include the photo metadata within. Both can be edited in Photoshop.

Would DNG be considered widely used today? I have a library of photos in NEF (Nikon D50) format that I have been contemplating whether to convert.

chills42
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Grant Palin
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  • Thanks for the feedback. I get the impression this is not something not to be rushed into, so I will sit on it for now, and investigate further. – Grant Palin Jul 21 '10 at 17:07
  • Only you can tell if it's worthwhile for you or not, so I'd suggest to reword the question to "what are the pros and cons of switching to DNG?". – Karel Aug 04 '10 at 05:54
  • If your reason for switching to DNG is that future software will better support it, that is almost certainly not true - there is a wealth of RAW editors out there and they support pretty much every manufacturer's RAW formats, and there are even open source RAW editors where this support has publicly available source code. – thomasrutter May 07 '15 at 04:31

8 Answers8

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Whatever you do, do not throw away your original RAW files. DNG is not a replacement for them. Perhaps your workflow requires you to convert into DNG's, but for the love of god do not throw away the originals.

If you do, then one day you will find that you will want to use a piece of software that doesn't support the DNG format as input.

Dave Van den Eynde
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    ... and at this point, there's really no point to having used DNG if you're also keeping the RAW files around. – ahockley Jul 15 '10 at 21:32
  • There might be, if you work for a company that uses a DAM system that works better with DNG's. – Dave Van den Eynde Jul 15 '10 at 21:34
  • @Dave, "If you do, then one day you will find that you will want to use a piece of software that doesn't support the non-DNG format as input." seems more likely. Are proprietary formats really more supported than the open ones? – Jonathon Watney Jul 17 '10 at 03:50
  • Yes. DxO Optics Pro, for instance, does not accept DNG for input. – Dave Van den Eynde Jul 17 '10 at 17:55
  • Sounds like DxO Optics Pro isn't on the ball. ;) – Jonathon Watney Jul 17 '10 at 18:30
  • Well, in their defense, they claim not all the required information is present in the DNG to stand up to the CR2 format. – Dave Van den Eynde Jul 17 '10 at 21:09
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    Curiously, I thought the idea behind DNG was future-proofing your files? – Grant Palin Jul 18 '10 at 01:38
  • A nobel idea, but until the camera manufacturers pick it up (and they won't, it's a matter of intellectual property) it's not very realistic. – Dave Van den Eynde Jul 22 '10 at 11:10
  • I believe there's an option to embed the original RAW file in DNG in case you want to extract it later.

    However, if you camera doesn't support writing compressed DNG natively, I'd probably wait.

    Otherwise, I'd convert to be future proof.

     – eruditass Jul 27 '10 at 03:58
  • DNG is an open standart, unlike proprietary raw formats. – Sirber Aug 04 '10 at 12:48
  • For what it's worth, I can still play Sim City on a DOS 6.22 computer I have in my closet, perhaps even in Parallels on my Macbook; although I've never tried.

    My point is, if you need to read an old file format, you can do it using equipment or software from that era and export to something more current or useful.

    As long as the media in which you stored the files current.

     – Chris Aug 04 '10 at 13:59
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    @Sirber: I don't see how that is an advantage, today. – Dave Van den Eynde Aug 05 '10 at 05:14
  • DNG is well supported in open source software due to the availability of dcraw. Since dcraw is distributed as software and the open source programs that use it are also distributed as source code and these programs run on open source operating systems also distributed as source code, the likelihood of waking up one day to a world where DNG is not supported is very very low. –  Nov 28 '17 at 17:13
  • @benrudgers likewise, the likelihood of CR2 and NEF not being supported one day is very low. – Dave Van den Eynde Dec 03 '17 at 12:19
  • The answer asserts that DNG will be unsupported someday. That assertion is unsupported by evidence. –  Dec 03 '17 at 15:02
  • I think you misread that. The answer does not suggest that one day DNG will no longer be supported. It asserts that one day you will find out that some piece of software that you want to use, does not support your DNG inputs while it does support native RAW formats. I gave an example of that. – Dave Van den Eynde Dec 03 '17 at 18:07
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agreed on not throwing away the original raw; Many import systems allow you to embed the RAW inside the DNG, so it's there if you need it; I personally do that on all of my images.

I use DNG primarily because that format includes the metadata sidecar as part of the DNG, where for RAW files, the metadata sidecar is generally a separate file. Bundling this all into one file simplifies workflow and makes it difficult to separate the two or lose the metadata, making housekeeping easier and reducing the risk of data loss. That alone made me decide to use DNG. It's convenient and if I ever need to unpack it, there are tools that can do it for me.

chuqui
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  • +1 I have just made this jump for this exact reason and now have incorporated it as part of my workflow in lightroom 3 – Wayne Nov 04 '10 at 10:54
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Think this way: maybe in the near future Capture NX may have a nice interface. You start using it but all your original NEF files are gone.

To my acknowledge Capture NX is one of the best sharpener for NEF files. Don't throw away your NEF files.

I was in the same situation as you. I converted all my NEFs to DNG. You know, DNG is "universal", smaller files etc. Big mistake. I wanted to edit some files in Capture NX but I couldn't because they were DNGs. I never converted a single NEF to DNG again.

And do backups of your files. Multiple backups.

cahuk
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  • This makes sense logically: if you can convert from A to B but there is no way to convert from B back to A, then it is better to keep your files in the A format so you still have that choice. – thomasrutter May 07 '15 at 04:33
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If you're happy throwing away the original RAW files then you can save a little disk space. I've converted CRW (Canon RAW) to DNG and I typically end up with files about 20% smaller with all the information there.

Of course disk space is cheap, and Canon and Nikon RAW formats are likely to be supported for a long time to come.

And Ricoh is another camera manufacturer who supports DNG - though that still leaves it fairly short of being widely supported by camera manufacturers. Though I would assume all major software packages should support DNG.

Hamish Downer
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It depends on what software you use to store/catalogue your photos. For example Lightroom understands NEF, and I'm perfectly fine with using NEF and not DNG.

Zepplock
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While Diskspace is cheap, RAW files continue to grow as well. My take: Converting to .DNG is not a bad idea at all. Why, because you should have a backup of you images anyways, so why not have a .DNG as a backup that does conserve some space at the same time. I would like to think that .DNG will not go away. It is such a common sense, no-brainer with respect to uniformity across software editors. Over time, if there are competing "open source" file formats, then conversion software will also follow that can convert .DNG to a new format.

Why it hasn't gained widespread acceptance is attributed to the proprietary attitudes of camera manufacturer's and the software they hope to sell to work with and view their "special" formats. I have used many Canon cameras and find that there are many Canon RAW file extensions such as .CR2, .CRW, and some software will not accept both formats, especially with respect to viewers.

Brian Bourassa
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Is DNG widely used? Not really. My Pentax K200D supported it, but not very well. Leica supports it in their S2.

NEF is very common (because Nikon is huge), enough so that I'm not worried about it going away. There is open-source software that can interpret current NEFs, so if (for example) Nikon disappeared tomorrow and took away all their software and specs and forbade third parties from creating NEF software, you could still get into the files.

I wouldn't bother converting preemptively.

Reid
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There's also an issue with software freedom:
while DNG is open, it's also patented and non-free, and it might be the reason why many people are reluctant to spend time and resources for it beyond the basics. As a result, DNG(output) is mostly supported in proprietary software, and free software usually only has minimal or even read only DNG support. So if you decide to routinely convert stuff to (losslessly compressed) DNG and later decide to stop using proprietary software, you'll have an unpleasant surprise because you might be unable to continue doing that.

Another possible issue:

Some photographic competitions do not accept converted files, and some do not accept DNG

(source)

Both issues can be sidestepped by keeping original versions too, but then the photos will take twice as much disk space.

Display Name
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  • The open source programs Darktable, Hugin, RAWtherapee, etc. all support DNG. This is largely because dcraw supports DNG. I love free software as much as the next person, but the assertion about DNG is incorrect. –  Nov 28 '17 at 17:09
  • @benrudgers They support reading DNG, but not writing. I wrote about the conversion to DNG. Do you know free software which can output losslessly-compressed DNG? – Display Name Nov 28 '17 at 17:28
  • All/most RAW files are written by proprietary software because cameras are proprietary systems. The flow to DNG is private proprietary RAW -> agnostic standard RAW. There isn't a compelling use case for going the other way, e.g. DNG -> CR2 and certainly not one grounded in Stallman's philosophy. The analog analog is Kodak's C41 process. It works with C41 film Fuji too...but there isn't an undeveloper that returns Fuli (or Kodak) film to its undeveloped state (though this might be more useful than a DNG reversal since the private proprietary RAW still exists. –  Nov 28 '17 at 18:43
  • @benrudgers proprietary software inside cameras is very limited in what kinds of damage it can do (camera can be viewed as a harmless black box), compared to software running on general purpose computers. It (usually) cannot connect to network, vulnerabilities in cameras don't matter, and it doesn't need to be updated to continue to function, so sabotage from vendor is unlikely. On the other hand, if your workflow needs some additional proprietary software running on general purpose computer which typically has access to all your data, etc., that's a different thing. – Display Name Nov 29 '17 at 07:17