# To DNG or not to DNG



## ARH18 (Jul 12, 2018)

Hi, sorry if this has been asked before but I'm struggling to find an answer!

I use a Nikon D750 and shoot in RAW (NEF). I transfer the NEF files to the hard drive on my mac from the camera card. When importing to Lightroom I have been advised to use the copy to DNG option, which I have been doing for a while. This gives me a few problems, one is that the storage is of course doubled, the original NEF file is never used as the DNG file is the one edited, if I choose to delete the DNG file from Lightroom and the hard drive it doesn't delete the NEF file which means I have a number of NEF files sitting on the hard drive which I don't want and if I forget to delete them through Finder then I'll never find them and continue to have wasted space.

So to my questions...

What's the advantage of copy to DNG over just importing the NEF files?

 Is there any reason to not edit NEF files directly?

What do others do, how to overcome wasted storage and making the NEF files redundant?

Is it worth keeping the NEF files once converted to DNG?

As ever with this type of software there are so many options and often the solution comes down to preference or opinion - help!!

Thanks,

Andy


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## Replytoken (Jul 13, 2018)

Welcome to the forum.  The DNG question is akin to Ford vs. Chevy or Coke vs. Pepsi.  There are advantages and disadvantages whether you choose to convert or not.  There are a large number of threads here in the forum if you want to go down that rabbit hole.  I would advise reading a few to give you an overview of what DNG can offer, but would not recommend loosing sleep reading too many threads/posts.

But to answer some of your questions, I would offer the following:

There is not reason not to edit the NEF files.  The changes will be kept in the LR catalog, and can be written to XMP sidecar files if need be.
I do recommend always keeping the NEF file.  You can always convert to DNG, but a DNG cannot be converted back to an NEF file.  True, you can store the NEF in the DNG files, but that now requires extracting it out at a future date, and if there is  a problem, you have now lost your original file.
I generally do not worry about space as storage is as cheap as it has ever been and continues to get cheaper.  If this is a concern, perhaps you should just stick to the raw file.
Goo luck,

--Ken


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## Dan Marchant (Jul 13, 2018)

ARH18 said:


> I use a Nikon D750 and shoot in RAW (NEF). I transfer the NEF files to the hard drive on my mac from the camera card. When importing to Lightroom I have been advised to use the copy to DNG option,


What reason did they give as to why you should copy to DNG? Or to put it another way what problem were you having? If the answer to these questions are "they said it was better" and "none" then stop converting to DNG and just use the NEF files.


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## LouieSherwin (Jul 13, 2018)

Hi Andy,

As Ken mentioned this is one of those hot topics. So you will likely get a number of replies. There are a several things that I think are worth considering.

There is no functional difference in Lightroom between the native raw file and the camera native raw file. All the benefits of working in raw are retained.
By using DNG in Lightroom you gain an internal checksum for each image. This means that Lightroom can check for file corruption. Very good for checking and maintaining integrity of you image library. 
Any time you save metadata including develop settings if requested, it is contained within the DNG file instead of being placed in an external XMP file. This means that you can send a DNG file to another Lightroom/Camera Raw user and they will see all the develop settings as well as any other metadata. 
DNG can contain a JPG rendition of your latest develop settings. Other image viewing applications can read this without directly without having to export to a separate JPG or TIFF. 
The main downside is that  while DNG open standard is not universally implemented. The major camera manufactures, Nikon, Canon, Sony, Fuji, etc., still don't support it in their own develop software. Also having not looked in a while I am not certain of the support status of DNG in the other major raw processing software, Capture One, DxO, ON1, etc.. Perhaps someone else can speak to that. 

Some claim that because the DNG standard is owned by Adobe that committing to it will lock you into  using Adobe software. My contention is that we are already "locked" into using Adobe by using Lightroom and  Adobe Camera Raw (ACR) parametric editing.  It is not possible render any of my images without the ACR settings AND the Lightroom or ACR regardless of whether they are in original raw  or DNG.  The advantage of DNG here is that does have the latest rendered JPG so you don't have to have any software to view developed image. 

I would say that the biggest attraction for me is the builtin checksum and that Lightroom can use that to validate all your archive. 

-louie


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## Johan Elzenga (Jul 13, 2018)

LouieSherwin said:


> Any time you save metadata including develop settings if requested, it is contained within the DNG file instead of being placed in an external XMP file. This means that you can send a DNG file to another Lightroom/Camera Raw user and they will see all the develop settings as well as any other metadata.


It also means that your backup utility will see the DNG file as changed, and so it will make a new backup.


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## LouieSherwin (Jul 13, 2018)

JohanElzenga said:


> It also means that your backup utility will see the DNG file as changed, and so it will make a new backup.



Yes, thanks for the reminder. This is why those who have adopted DNG do not automatically write to XMP.

-louie


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## Replytoken (Jul 13, 2018)

LouieSherwin said:


> Hi Andy,
> 
> As Ken mentioned this is one of those hot topics. So you will likely get a number of replies. There are a several things that I think are worth considering.
> 
> ...


I think Louie did an excellent job summing the major advantages of using the DNF file format and has saved you from reading a large number of threads/posts/articles!

--Ken


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## Replytoken (Jul 13, 2018)

JohanElzenga said:


> It also means that your backup utility will see the DNG file as changed, and so it will make a new backup.


And Johan touched upon another one of the glass is half full/empty issues of DNG files.  Some people like them as they do not like having XMP files along with their image files.  But, if the image file is never altered, backing up just a small XMP file is much quicker than a DNG file, especially if you embedded the original within it.

--Ken


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## PhilBurton (Jul 13, 2018)

LouieSherwin said:


> Yes, thanks for the reminder. This is why those who have adopted DNG do not automatically write to XMP.
> 
> -louie


Writing to XMP would be redundant.

However, any change in a DNG file due to editing an image could trigger an automatic backup of the entire multi-MB DNG.  Using an NEF or CR2, an editing change would affect only a small XMP file, typically only a few KB.

Phil Burton


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## ARH18 (Jul 13, 2018)

Wow - thanks all for your replies, this is really useful and some excellent food for thought.

Dan - the reason given for using DNG rather than NEF was that DNG is manufacturer agnostic and would be fully supported by Adobe whereas there is a risk (probably minuscule) that NEF files may not be supported fully in the future.

I'm not a professional photographer and I edit probably 20% of my images (other than applying presets on import), some of the reasons for having DNG such as sharing with other people and avoiding XMP files are not really issues for me, so my conclusion is that I think I'll stick with just the NEF files. I guess I can always convert the odd one or two to DNG as and when need arises.

Thanks again everyone for your views and advice, really helpful.

Cheers,

Andy


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## Linwood Ferguson (Jul 13, 2018)

ARH18 said:


> Dan - the reason given for using DNG rather than NEF was that DNG is manufacturer agnostic and would be fully supported by Adobe whereas there is a risk (probably minuscule) that NEF files may not be supported fully in the future.


The component this aspect often misses is one of time -- even if true that some camera may lose support (it hasn't happened so far as I'm aware), you will have notice.  You can always convert later, before it happens.  Converting on the speculation it might happen (if that's the primary reason) gains you nothing really, since you can make that conversion IF it happens.   And trust me as soon as Adobe stops supporting cameras, you WILL hear.

A lot of good info above, but I leave this one thought:   You need a compelling reason, compelling to you, to convert.   Don't let people just say "best practice" and follow their lead.  Yes, there are some good reasons to, and not to... evaluate it for you. But ask "should I".  I see people all the time asking "why not".  To me that's the wrong question.


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## pknoot (Jul 14, 2018)

I've been using DNG files ever since the feature was available.  For me, not having the XMP files is a plus, since it's a problem if any of these are lost or corrupted during backup operations.  My concern with camera-specific RAW files is support by the manufacturers for the formats in the future; in principle the DNG format is immune to obsolescence.  I do not use Canon's editing programs, because I have Lightroom!


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## Linwood Ferguson (Jul 14, 2018)

pknoot said:


> For me, not having the XMP files is a plus, since it's a problem if any of these are lost or corrupted during backup operations.


Actually if you are a lightroom user the XMP files are totally redundant, you can lose them all, and nothing bad happens; you could recreate them all if you need to.   The data is all in the catalog (indeed, not all catalog data is in the XMP's).


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## PhilBurton (Jul 14, 2018)

pknoot said:


> I've been using DNG files ever since the feature was available.  For me, not having the XMP files is a plus, since it's a problem if any of these are lost or corrupted during backup operations.  My concern with camera-specific RAW files is support by the manufacturers for the formats in the future; in principle the DNG format is immune to obsolescence.  I do not use Canon's editing programs, because I have Lightroom!


Let's get real here.  Canon's CR2 and Nikon's NEF will be support by at least one RAW developer for years and years to come.  If LR dropped NEF, for example, then people like me would just have to switch to CaptureOne or a similar product.  And LR competitors will put out strong messages about their continued commitment to NEF. 

On the other hand, if your RAW file is from say Pentax, just using an example here, then maybe you should be concerned.  At some point, LR management might look at user statistics (for LR 7 subscribers, of course), and conclude that they are spending a lot of money to test each release against Pentax PEF files and market shares don't justify the expense.

But if your RAW files are Canon or Nikon, you have nothing to worry about.   There is so much misinformation and huffing-and-puffing floating around.  That said, there are legitimate reasons for using DNG.  However, if you are at all concerned about "Adobe lockin" search out how many other RAW developers also support DNG.

In the interests of full disclosure, my camera is a Nikon D3 and I do not use DNG.

Phil Burton


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## Johan Elzenga (Jul 14, 2018)

Even if you shoot Pentax raw, you have nothing to worry about. As was said before, if and when it ever happens that the next version of Lightroom does not support your raw files anymore, you could simply convert them to DNG right there and then, before you upgrade (or simply don’t upgrade). It’s silly to worry now over something that may never happen and is easy to solve if it does ever happen.


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## Tony Jay (Jul 15, 2018)

Just to correct a fallacy here: the DNG standard is NOT owned by Adobe. It is a completely open format, and there are no license conditions or fees that stop anyone from adopting it.

The fact that Adobe developed the DNG format is a different issue. The DNG format is awaiting standardisation by the ISO.

Until the DNG format becomes an ISO standard, and becomes more widely adopted across the industry I feel that there is not really an imperative to convert my raws to DNG.
However, I really believe that DNG should be adopted as a universal raw format, and that its ultimate role should be as a long-term archive format.
Until then...

Tony Jay


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## PhilBurton (Jul 15, 2018)

Tony Jay said:


> Just to correct a fallacy here: the DNG standard is NOT owned by Adobe. It is a completely open format, and there are no license conditions or fees that stop anyone from adopting it.
> 
> The fact that Adobe developed the DNG format is a different issue. The DNG format is awaiting standardisation by the ISO.
> 
> ...


"The nice thing about standards is that there are so many of them."  Attributed to some engineer I worked with a long time ago.  There are standards and there are standards.  Most standards are voluntary.  Without the force of law companies can choose to adopt or ignore standards. 

In our own little area, there was an initiative that got started in 2005 to promote an open RAW format.  Read about it here.  OpenRAW - Digital Image Preservation Through Open Documentation and here The RAW Problem | OpenRAW.  Note the dates, 2005 and 2006.  If I remember correctly, the leaders sent letters to the major camera manufacturers asking for support and Sony (if I remember correctly) actually responded.  Their letter was the typical response when a company feels it has to say something but doesn't want to say anything.  Sorry that I can't locate the URL of that letter.  Update:  I found that letter.  Sony responds to 2006 RAW Survey report | OpenRAW.  Sony is committing to nothing.

From my direct experience, ISO is a very slow-moving organization.  Without pressure from the leading camera manufacturers or software developers there is no real incentive to move forward.

It's now 2018.  Has Nikon or Canon adopted DNG?  Leica has, but Leica (sadly) is such a small part of the market these days that they probably would not get support from software companies for a proprietary RAW format.  Canon and Nikon are both strong players.  What incentive is there for these companies to move to DNG?  Software companies have to support their RAW formats.

We will be dealing with CR2 and NEF for a long tie to come.


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## Tony Jay (Jul 15, 2018)

PhilBurton said:


> "The nice thing about standards is that there are so many of them."  Attributed to some engineer I worked with a long time ago.  There are standards and there are standards.  Most standards are voluntary.  Without the force of law companies can choose to adopt or ignore standards.
> 
> In our own little area, there was an initiative that got started in 2005 to promote an open RAW format.  Read about it here.  OpenRAW - Digital Image Preservation Through Open Documentation and here The RAW Problem | OpenRAW.  Note the dates, 2005 and 2006.  If I remember correctly, the leaders sent letters to the major camera manufacturers asking for support and Sony (if I remember correctly) actually responded.  Their letter was the typical response when a company feels it has to say something but doesn't want to say anything.  Sorry that I can't locate the URL of that letter.  Update:  I found that letter.  Sony responds to 2006 RAW Survey report | OpenRAW.  Sony is committing to nothing.
> 
> ...


You may be right...

Tony Jay


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## Linwood Ferguson (Jul 15, 2018)

PhilBurton said:


> What incentive is there for these companies to move to DNG?  Software companies have to support their RAW formats.



There's actually quite some dis-incentive, in that they then have more trouble innovating.  If there are new features that must be saved in the file, even if there are areas that are described as "whatever you want to put here", anything proprietary that a manufacturer puts in a "standard" file gets them grief for breaking programs that use the "standard" file.  Anything proprietary they put in their own proprietary file is ... well, just normal.

Unless you plan to be a commodity, marketing is all about being distinctive.  It's rarely considered distinctive to be "standard". 

So commiting to (only) a standard output file is limiting.

Supporting both proprietary and standard is ultimately rather pointless, like trying to cheer for both teams at the World Cup final - you'll be hated by both sides of the argument as opposed to loved by them.


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## PhilBurton (Jul 16, 2018)

Ferguson said:


> There's actually quite some dis-incentive, in that they then have more trouble innovating.  If there are new features that must be saved in the file, even if there are areas that are described as "whatever you want to put here", anything proprietary that a manufacturer puts in a "standard" file gets them grief for breaking programs that use the "standard" file.  Anything proprietary they put in their own proprietary file is ... well, just normal.
> 
> Unless you plan to be a commodity, marketing is all about being distinctive.  It's rarely considered distinctive to be "standard".
> 
> ...


Proprietary formats (and protocols) are a way that strong companies maintain and extend their competitive strength in a marketplace.  Standards are a way that weak companies can gang up on strong companies to pull them down to a commodity.  Or it's the strong company that "sets the standard" that every other company has to chase.   That's why Nikon and Canon will not adopt DNG (or once upon a time, OpenRAW).  It's all about competitive advantage, or lack thereof.

Phil Burton


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## Tony Jay (Jul 16, 2018)

PhilBurton said:


> Proprietary formats (and protocols) are a way that strong companies maintain and extend their competitive strength in a marketplace.  Standards are a way that weak companies can gang up on strong companies to pull them down to a commodity.  Or it's the strong company that "sets the standard" that every other company has to chase.   That's why Nikon and Canon will not adopt DNG (or once upon a time, OpenRAW).  It's all about competitive advantage, or lack thereof.
> 
> Phil Burton


With respect to file formats this actually makes no real-world sense.
The DNG format is based on the TIFF-EP standard.
And so is every modern proprietary raw format...

There is no competitive advantage here - they all use the same stuff - but it is not openly admitted.
This is a bit likely an electrical utility company trying to tell you that their electricity is better than everyone else's...

Tony Jay


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## Linwood Ferguson (Jul 16, 2018)

Tony Jay said:


> With respect to file formats this actually makes no real-world sense.
> The DNG format is based on the TIFF-EP standard.
> And so is every modern proprietary raw format...
> 
> ...


Yes, exactly.  I believe it is smoke and mirrors, but smoke and mirrors powers our economy.  Sad perhaps, but oh so true.  

The more standard a company appears, the more its product begins to look like a commodity.  To Marketing types, that's a death knell.   It's like a sign saying "my product is no better than my competitor".  Sure, we're just talking storage formats, but marketing types fight for every possible market distinction.

Tell me why Apple won't use a standard USB type connector?    (Or pretty much anything standard).   Is there really a functional difference in their connector and a USB-C that merits the difference?


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## Johan Elzenga (Jul 16, 2018)

Ferguson said:


> Tell me why Apple won't use a standard USB type connector? (Or pretty much anything standard). Is there really a functional difference in their connector and a USB-C that merits the difference?


Bad comparison. The connector on Apple computers is fully USB-C compatible, but Thunderbolt 3 (_which is also a standard_) offers more options and more speed than USB-C. The Difference between USB-C and Thunderbolt 3 | Thunderbolt Technology Community


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## Linwood Ferguson (Jul 16, 2018)

JohanElzenga said:


> Bad comparison. The connector on Apple computers is fully USB-C compatible, but Thunderbolt 3 (_which is also a standard_) offers more options and more speed than USB-C. The Difference between USB-C and Thunderbolt 3 | Thunderbolt Technology Community


I'm talking about the other end, for iPhone and iPads, and why my wife and I have to carry different cables whenever we change cards and want a charger. 

But that's the minor details, and indeed there's always some rationale people use for being non-standard, but at its core is to go their own way, to distinguish themselves from others, to put their own unique signature on something.  There's a perception that "standard" = "Ordinary" = "Average" and no one wants to be average; worse no one wants to ADVERTISE that they are average.

But honestly we are way off the topic of whether a user should DNG or not -- whether a vendor should is speculative, as they won't listen to us.  Whether a user should is more concrete, as they might.   I can't handle the responsibility.


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## LouieSherwin (Jul 16, 2018)

Ok enough said. Everybody's  input is appreciated. I believe that Andy's question was sufficiently answered and this discussion is heading far a field. 

tks,

-louie


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## ARH18 (Jul 12, 2018)

Hi, sorry if this has been asked before but I'm struggling to find an answer!

I use a Nikon D750 and shoot in RAW (NEF). I transfer the NEF files to the hard drive on my mac from the camera card. When importing to Lightroom I have been advised to use the copy to DNG option, which I have been doing for a while. This gives me a few problems, one is that the storage is of course doubled, the original NEF file is never used as the DNG file is the one edited, if I choose to delete the DNG file from Lightroom and the hard drive it doesn't delete the NEF file which means I have a number of NEF files sitting on the hard drive which I don't want and if I forget to delete them through Finder then I'll never find them and continue to have wasted space.

So to my questions...

What's the advantage of copy to DNG over just importing the NEF files?

 Is there any reason to not edit NEF files directly?

What do others do, how to overcome wasted storage and making the NEF files redundant?

Is it worth keeping the NEF files once converted to DNG?

As ever with this type of software there are so many options and often the solution comes down to preference or opinion - help!!

Thanks,

Andy


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## PhilBurton (Jul 16, 2018)

Tony Jay said:


> With respect to file formats this actually makes no real-world sense.
> The DNG format is based on the TIFF-EP standard.
> And so is every modern proprietary raw format...
> 
> ...


Tony,

If various RAW formats and DNG are all based on the same TIFF standard, then "logically" Nikon's discontinued Capture NX 2 should be able to process Canon CR2 or a DNG file.  Of course, we all know that is not possible.  Or any RAW developer software should be able to process a DNG. 

The "standard" is the totality of what's in it, not just a component included from other standards.  I've worked with people who sit/sat on standards organizations, and standards organizations try and use as much as possible from other standards, e.g. every standard that uses text probably uses ISO 639, ISO 639 Language codes.  Why do anything different?

Look at market dynamics.  Nikon and Canon believe that they can be more innovative if they don't use DNG in preference to their own RAW formats.  Microsoft created its own "standards" with Office.   About 20 years ago, Microsoft adopted the "embrace and extend" strategy.  Read this for me detail, and then tell me if you think that standards don't matter.  Embrace, extend, and extinguish - Wikipedia.  I worked at Sun Microsystems when Java first became popular and then watched Microsoft effectively destroy Java on the desktop.  About the same time, I saw firsthand how Microsoft used its market dominance to successfully attack the Netscape browser.  For a while, I worked as a business partner to Netscape, and they were powerless to stop the attack.

I think we have beaten this topic to death.  I hope everyone will realize that CR2 and NEF will be around for a long time, with full support from the relevant software companies.

Phil Burton


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## Tony Jay (Jul 17, 2018)

PhilBurton said:


> Tony,
> 
> *If various RAW formats and DNG are all based on the same TIFF standard, then "logically" Nikon's discontinued Capture NX 2 should be able to process Canon CR2 or a DNG file.  Of course, we all know that is not possible.  Or any RAW developer software should be able to process a DNG.*
> 
> ...


Your logic is flawed here - one does not need to change very much to make a raw format unique.
I would suggest that your research, and therefore knowledge of file formats is lacking...

The fact is that every modern proprietary raw file format is indeed based on the TIFF-EP format (strangely enough another Adobe invention that has now ISO standardisation).

Yes, it appears that the topic has indeed been beaten to death - by those with entrenched "don't confuse me with facts" attitudes!

Tony Jay


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