What are the reasons for NOT using DNG instead of NEF (or CR2)?

[PhilBurton]

I keep reading here and in the Lightroom forum why I should convert my NEFs to DNG format. I'm still skeptical.

For PSu, what are the advantages of using DNG? I use Lightroom as my image editor and publisher.

Thanks. (Putting on my Kevlar underwear now. )

Phil

[PhilBurton]

I keep reading here and in the Lightroom forum why I should convert my NEFs to DNG format. I'm still skeptical.

For PSu, what are the advantages of using DNG? I use Lightroom as my image editor and publisher.

Thanks. (Putting on my Kevlar underwear now. )

Phil

Anyone?

Phil

[weidmic]

I stopped converting all my RAW (NEF) into DNG because I wanted to work not only with LR
Capture One and DXO are now in my workflow family and I figured that RAW files coming from my camera are best supported...

A second reason is time - converting all the big files from my D800/D810 is very time consuming, even with a fast computer!

The advantage in using DNG is that you can embed a full preview into the DNG - which can be seen by PSU and other software.

Cheers,
Michael

[Mke]

If I were you, I'd remain sceptical and stick with native formats

[fbungarz]

If I were you, I'd remain skeptical and stick with native formats

Actually, I think there are advantages of both formats. And even good argument to keep both!

DNG:
DNG stores previews and is fully XMP compatible, i.e., XMP is embedded inside the file. The format generally works well with Adobe products (lightrrom, Photoshop).
Also there are several camera brands on the market that use DNG as their native raw format (including some high-end brands like Leica).

An additional argument often forwarded by Adobe is that DNG is more future-proof. In the digital age each new camera creates new types of RAW files. So one NEF is not the same as the next NEF, one CR2 not the same as the next CR2. That argument is a bit redundant though, because specifications of the DNG format have been updated/upgraded a few times since the format has been released. But: compared to native RAW formats, DNG is not proprietary, the source code specifications open to anyone. So, DNGs are possibly also the better choice with some freeware RAW converters like Raw-Therapee.

Finally, camera companies may go bankrupt and then support for their RAW file formats will, at least in the long run, likely disappear from the market. Even the biggest brands are actually not immune. A good example is Kodak. Rumors have it that Nikon and Canon SLR struggle quite a lot with the new competition from mirrorless cameras (particularly Sony). Of course one might argue that even DNG is not completely immune to this, Adobe after all might at some point go bankrupt too, but DNG then likely has a much broader market share than any proprietary format.

NEF / CR2 - native, proprietary formats:
Most native camera RAW formats do not store previews and most include only a very limited set of metadata (e.g. exif). In fact, writing XMP into these files bears a high risk of image corruptions, the formats were not originally designed for that purpose. That is why PSu per dfefault has metadata-writing to these files disabled per default. XMP is typically stored as sidecar files. This has the obvious disadvantage that the metadata are kept separately from the original file and the two files need to be distributed in pairs, if one intents to share metadata and image data together.
This obvious disadvantage can be seen as an advantage though: Image Management software like PSu do not touch the actual image file and only update the XMP. Thus the chance that the original file becomes corrupted is lower. Only the sidecar file is being updated, not the NEF or CR2 itself.
I have actually experienced both scenarios: corrupt DNG files (likely caused by metadata corruption) and NEF files that no longer could be opened, because I had at some time enabled IDImager (not PSu) to write XMP to the image itself.

Though Adobe generally strongly supports DNG, they cannot afford to ignore original raw files, I guess one does actually not notice much of a difference editing NEFs or DNGs in Lightroom or Photoshop. Some non-Adobe RAW converters, however, do not really support DNGs. Particularly PhaseOne (C1) does not really work well with DNGs. DxO, however, works quite well with either one.

There are probably several other reasons too to prefer either DNGs or native RAW formats.

Conclusion
So, what is my own final conclusion?

I generally keep both, NEFs and DNGs (I do not own any Canon gear). To me that seems the most future-proof approach. Yes, it seems like redundant storage overhead, but here are my reasons:

NEFs not touched by PSu remain a "pure" backup version of my images. But I also like that I can easily share the DNGs with their metadata included inside. The extra costs of keeping both files are minimal: PSU facilitates to keep them versioned, so there is little management overhead to keep both files. The costs of additional storage (hard disk space) is, in my view, outweighed by the fact that keeping two versions is an additional safeguard against image corruption, especially copy-errors. Yes, one can keep backups, backups, backups - but any backup is a copy of the original file and that copy process is not immune to error.

One final advantage of keeping both: Had I decided years ago tho throw away my NEFs and just keep the DNGs I could now not use PhaseONe (C1) a software that only fairly recently came onto the market. But then, who knows if in 20 years any software will still be able to open the images from my Nikon Dx2...

The only strategy that I would NOT advocate though are DNGs that have a full NEF as a second copy embedded inside. That, in my opinion is really redundant. DNGs that include the original NEFs are huge. Just keeping the NEF as a copy is, in my opinion, the better strategy.

And if you are really concerned, about hard disk space: you can always keep only the NEF (or CR2) and convert these files to DNG should the necessity arise... (depriving yourself of the slight advantage of keeping two copies for safety).

Cheers,
Frank

[PhilBurton]

Frank,

Thanks for this useful explanation. I also asked a friend of mine (who happens to use Canon) what he does. he was very dogmatic. DNG = Good. NEF or CR2 = stupid. No room for discussion. I like your idea of creating DNGs as insurance, or maybe I'll end up keeping the NEFs as insurance. Disk space is cheap these days. For $160, I can a buy a 4 TB drive that is probably the most reliable of the field. http://www.newegg.com/Product/Product.a ... 6822145912. I have 3 or 4 of these drives already, which is use for backups, 1 drive per year.

Phil

[lippe]

Hi Phil,

I once started converted all RAW files to DNG because I thought that only DNG was future proof, and all other raw formats will cease to exist or will no longer be supported. Several moths later, i deleted all DNG's and restored the original raw files from backup.

After several years, (Lightroom has gone from 2 to 6, Photo Supreme was born, FastPictureViewer is still lightning fast) I'm still happy with that decision.

It takes to much time to convert RAW to DNG, even on a fast machine. On a slower machine the fun is completely gone.
The option for Incorporation of the original RAW into the DNG is blowing up the file resulting in slower processing. And i don't wanted to take the risk by trowing away my originals. So it doubles the files to handle.
FastPictureViewer, Lightroom, Photo Supreme are handling the XMP buddy files well, the risk of loosing the the xmp is negligible.
Lightroom and Photo Supreme have both previews.
Updating the XMP only in the database and xmp buddy file is faster as updating DNG's.
An incremental backup has less data to update as the raw files do not change during editing and updating meta data.
Whenever i like, i can use an other raw converter.

But I like the DNG format for merging RAW files (HDR and panoramic image). I don't have to redo the converting steps when i change my mind about the final retouching. I keep the originals anyway so i can the start from scratch or develop multiple versions.

So I do not agree with your friend that NEF or CR2 are stupid. And i agree also DNG has it advantages. I embrace both formats.
With all arguments already mentioned by Michael, Frank, you can make your own decision. That will be the best solution for your situation.

Greetings, Lippe

[fbungarz]

Just one comment: For me the time to convert the file are not much of an issue because I do that automatically during import as a background routine...
I cull images with FastPicture Viewer, then import to PSU, applying metadata sets, versioning, etc. So, in my case importing images is a time consuming process anyway and the RAW -> DNG conversion does not add all that much overhead.
But workflows are different and I agree: if you do the conversion on-the-fly only when needed it can slow you down, taking the fun out of it...

[PhilBurton]

Hi Phil,

I once started converted all RAW files to DNG because I thought that only DNG was future proof, and all other raw formats will cease to exist or will no longer be supported. Several moths later, i deleted all DNG's and restored the original raw files from backup.

After several years, (Lightroom has gone from 2 to 6, Photo Supreme was born, FastPictureViewer is still lightning fast) I'm still happy with that decision.

Greetings, Lippe

Lippe,

Thanks for your reply. I had pretty much decided to stay with NEFs for now. After reading your reply I feel I made the right decision.

It just occurred to me that I should download the current version of Adobe Camera RAW, which is 9.4. So if for some reason Adobe drops support for my Nikon D3 NEF in ACR 10, I'm still covered.

I've seen the argument made in several places that ACR no longer supports a Kodak RAW format. Kodak was late to the digital game, and has never seemed to get their digital strategy right. it's not reasonable to compare Adobe's decisions about Kodak with Nikon or Canon.

By the way, what is truly sad (or stupid) is that Kodak invented digital imaging in 1975.

Phil

[fbungarz]

it's not reasonable to compare Adobe's decisions about Kodak with Nikon or Canon.

Just to clarify:
That is not actually what I suggested. I simply used Kodak as one example where a dominant, well established company suddenly was left in the dust, because it missed the right turn. That can easily happen to any big player, even Nikon or Canon. The digital world just has this kind of bang and bust dynamics...
So, I was not referring to Adobe's decision no longer to include Kodak in their ACR, but the fact that virtually from one day to the next Kodak went bankrupt. And once companies are out of business support for their legacy data are much more likely to be dropped than if they are still around...

[Preston B]

I tried DNG a long time ago and it didn't offer much for me, except for larger files. Now, I stick with ACR to convert my NEF files and then save them as PSD files. Aside from minor corrections in ACR, I use Photo Shop CS6 for more refined editing.

Some of my PSD files from NEF's get pretty large; approaching 2 GB, so keeping the files as small as possible is worthwhile for me.

--P

[lippe]

Phil, I missed a one of the greet advantages of DNG when using Lightroom (Develop module) / ACR. Both verifying the hash code in the DNG to detect errors in the file.
I tested this in Lightroom by changing one bit in an hex editor of a DNG file. When opening the file in the develop module, a banner is displayed indicating the error.
Unfortunately, there is no easy way to check multiple files. (http://www.dpbestflow.org/data-validati ... validation)

Gr, Lippe

[PhilBurton]

Lippe,

DNG uniquely seems to address the issue of "bit rot." That is one reason why I have a backup strategy based on a small-business product called Retrospect, www.retrospect.com. In brief, Retrospect can save multiple versions of a file, and do retrievals based on any date in the past, since it creates a "snapshot" of every backup including files that have not changed. I have been able to retrieve files that were several years old using this approach.

Phil

[sanphotgn]

Phil,

Are you using the byte for byte comparison in Retrospect? I used Retrospect back in the day when it was with Dantz. I stayed with it when it went to EMC, but gave up after it was sold to the next company.

Kevin

[PhilBurton]

Phil,

Are you using the byte for byte comparison in Retrospect? I used Retrospect back in the day when it was with Dantz. I stayed with it when it went to EMC, but gave up after it was sold to the next company.

Kevin

Yes.

You might want to give Retrospect another try. I don't want to go off-topic so I won't say more here.

Phil