# Is DNG still viable?



## Nathan Smith (Apr 3, 2018)

For the last several years I have always converted my Nikon RAW files to DNG. I did this for 1. "future proofing" my files and 2. to save space. One year ago I switched to shooting 100% Fuji, and continued to do this. However, recently, with my XPro2 and XT2 bodies, Fuji's compressed RAW makes the RAF files 25MB versus 50MB, BUT now when I convert these to DNG files they swell to 30MB each. In the past it SEEMED that Lightroom Classic was a bit faster when working with DNG files vs Fuji RAF (RAW) files, which actually makes sense, since it is a more "Adobe friendly file", but now I'm not so sure. Of course the initial converting to DNG is painfully slow, and with now larger files, I'm wondering if there is still any benefit. Any thoughts on this?


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## clee01l (Apr 3, 2018)

On the off chance of Nikon coming out with a better post processor to handle Nikon Specific metadata, I have kept the original NEF file  and not converted to DNG.  The space saved to convert to DNG is trivial and as long as Nikon is around, every post processor will handle that RAW data.   Should the NEF file become obsolete, I think I will have ample time to convert those NEFs to DNG with the latest RAW conversion technology,.   Importing NEFs without converting is faster than when adding the extra step of converting to DNG in the import process.   I have maintained this philosophy with the X-Trans files from my Fuji as well.
You can't go back to the NEFs and RAFs if you did not keep them.   Converting the RAFs to DNG takes a broad leap of faith that Adobe got the conversion process right for the X-Trans files.  Early efforts by Adobe to de-mosaic the X-Trans files was not initially successful.   What if On1 or CaptureOne develop a better RAW conversion engine than Adobe's ACR?  You are going to be stuck with Adobe's rendering if you don't keep the original proprietary RAW files.


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## tspear (Apr 3, 2018)

Depends on your reason to convert to DNG. Based on your posted reasons, the answer is no.
For me, the primary reason is help prevent bit rot with the built in hash check.  In which case, the need for DNG still applies and is a nice bootstrap.
The most significant downside given to DNG (that I hear) is that at some point Fuji, Canon or someone discovers some new super process to get better data/results from some hidden meta-data.  This has not happened in over twenty years, so while it is still possible, I am thinking this is more and more unlikely (camera companies have actually gotten closer to each other at the chip and low level data structures).


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## Ian.B (Apr 4, 2018)

For me, DNG are still viable, and needed as my newer camera files (lumix FZ300) cannot  be read by my older Lr5. Bit of pain having to run the files through Adobe DNG converter but it doesn't take much time. I  leave the converter set to convert raw files in a "New raw files" folder and send the new dng files to the  "new pics" folder so I don't lose track of them. The original files are  deleted --- _shock horrors_ move says  Glee  
Converting to dng also allows the viewing of images in windows.  
I sort of feel the "space saving"  part of dng is lost now with so many affordable digital storage ways available.
With no intentions of going any further past  Lr5, I am stuck with dng for awhile yet


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## Lungdoc (Apr 8, 2018)

Not for me - at least with the new Canon CR3 files. Using the new  C-Raw option file sizes 19-27 MB, same typical 20 MB file is about 97 MB(!!) when converted to DNG. I will opt for the disk space every time (I'm shooting family/fun personal stuff, and a tiny theoretical loss from lossy compression  is irrelevant to me). I was a DNG user until now.


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## Tony Jay (Apr 9, 2018)

I have not changed my workflow to use DNG files as raw files.

However, I am very for the idea of a universal raw format (DNG is the only credible candidate for this title on the horizon).
I understand that ISO standardisation for the DNG format is in process now.
This is an obligatory first step for the DNG format to becoming a universal raw format.
Until this first step is achieved, despite the DNG format already being an open format and accessible is every way to all camera manufacturers and software houses producing imaging software, the DNG format will not achieve universal acceptance.

Ultimately, in years to come, the DNG format will become a de facto currency in the imaging world, like the JPEG and TIFF formats.
Every camera manufacturer these days, even if they do not explicitly use the DNG format, actually implicitly use it!
All those proprietary raw formats are based on the DNG specification (which does make it easier for Adobe, Capture One etc to reverse engineer all the new raw formats released with every new camera) in any case, but a lot more work needs t be done to get the whole industry on board as to the importance of a universal format.

So, the full potential of the DNG format is still some time away from being fully realised!
For now, I will continue to with my current practice of using proprietary raw files while looking forward to the day that allows one to just use a universal raw format!

Tony Jay


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## mcasan (Apr 9, 2018)

I find no compelling reason to do dng.   Evidently most camera makers agree.


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## johnbeardy (Apr 9, 2018)

Remember that any file saving is not a good reason for using DNG - it is merely a side effect. And space is cheap.

Better reasons for adopting DNG are that:

unlike proprietary raw files, it is a publicly-documented archival format
it can be validated by check sum
the single file contains both the image data and any editing work that you've done on it.  With no Adobe software on a computer, DNG lets you output the photo exactly as I edited it.
Camera makers pursue their own interests. Those aren't identical to photographers'.  That should be obvious every time people ask why Lightroom doesn't allow them to import photos from their new camera. 

John


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## Lungdoc (Apr 9, 2018)

johnbeardy said:


> Remember that any file saving is not a good reason for using DNG - it is merely a side effect.


Except at 3:1 for CR-3 CRAW files that side effect is a) in the wrong direction b) too much of a penalty to be worth the other benefits, to extend the medical metaphor the therapeutic ratio of DNG (benefit to drawbacks) has changed. I also find that with the newer ability to use the embedded jpg in import/preview (and set preference to allow computer to generate the better previews in the background when resources available) the import speed is much faster. YMMV.


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## johnbeardy (Apr 9, 2018)

Review the DNG conversion options that you are choosing. That kind of increase in file size makes me think that you are saving in demosaiced (lossy) format.


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## Lungdoc (Apr 9, 2018)

Thx. I will try different options this evening. I don't recall ever changing the default, possibly used the lossy DNG option in prior LR4 and it got picked up in update to LR7, but if I did the only reason I would have used in the first place was that lossy was supposed to be smaller not larger.


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## Lungdoc (Apr 9, 2018)

If anyone else wants to play around w CR3 to DNG conversion and options there are public sample files here. I'm here to learn...  Canon EOS M50 Review - Preview Images | Photography Blog


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## Jim Wilde (Apr 9, 2018)

I downloaded 4 of those raw files and converted to DNG on import the Lightroom. In all case there was a slight increase in image size (37MB to 41MB), but nothing like your experience. So I'd guess it's either as John speculated, or you've embedded the original Raw file into the DNG.


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## johnbeardy (Apr 9, 2018)

Lungdoc said:


> If anyone else wants to play around w CR3 to DNG conversion and options there are public sample files here. I'm here to learn...  Canon EOS M50 Review - Preview Images | Photography Blog



I came back to this thread intending to ask if you could make available some sample files.... And you'd already done it. Thank you!

John


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## johnbeardy (Apr 9, 2018)

I just looked at 2 files and in each case the DNG was slightly smaller. Maybe take a look at the DNG view of the Metadata panel? If you see Mosaic Data reading No, the file has been demosaiced and would be roughly 3 times bigger. Embedding the original raw file would also increase the file size.

John


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## LouieSherwin (Apr 9, 2018)

johnbeardy said:


> Remember that any file saving is not a good reason for using DNG - it is merely a side effect. And space is cheap.
> 
> Better reasons for adopting DNG are that:
> 
> ...



Nice concise summary of the important value added by using DNG. 

I would like to add another one specific for my Sony AR7II. When shooting uncompressed raw the file size is 80MB+. Converting to DNG reduces that size down to about 40MB. This is about the same size as the compressed raw but I believe it is lossless compression whereas the Sony compressed is lossey. 

-louie


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## Roelof Moorlag (Apr 9, 2018)

I just tested 2 of those files and in each case the DNG was slightly smaller too.


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## Lungdoc (Apr 9, 2018)

Thanks everybody! I realized in hindsight that I had created those DNG's directly with the DNG converter (not Lightroom) and just used the default settings. Was a blur of a weekend as a new camera and tested ON1, Lightroom CC and Classic CC (was on LR4 before...) in rapid succession to see what would work for me (Classic CC as it turns out). Nice to know I can stick with DNG, although the import speed might still sway me to a CR3/sidecar workflow. Adobe might rethink the default settings on the converter....


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## Ian.B (Apr 9, 2018)

would certainly make it so much easier and sensible Tony to have just one RAW file like DNG. I believe that is why dng was introduced in the first place -- correct me if I'm wrong as you have a greater understand of such matters
Whoops!!! I typed that yesterday 
I need another sticky on the screen to say "click on post reply"


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## Hoggy (Apr 10, 2018)

I'm still going to be converting to DNG.  For all the reasons John mentions.  Plus the smaller size will mean I use that many fewer BD-r/BD-re50's for what is actually my primary backup method ATM.  Right now I toss originals, but I'll still likely continue that when I get my new supercomputer soon.  I would never bother to learn software that would make any supposed use out of additional metadata anyways (which, BTW, is still kept within the DNG - whether or not if software would use it).

However, an often overlooked benefit for DNG that's rarely ever stated - at least with converted DNG, not sure about native - is the Tiling aspect.  DNG conversion makes DNG's in a tiled fashion, to make better user of multiple CPU-cores.   (Why am I about the only one that ever seems to mention that??  )


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## Tony Jay (Apr 10, 2018)

Ian.B said:


> would certainly make it so much easier and sensible Tony to have just one RAW file like DNG. I believe that is why dng was introduced in the first place -- correct me if I'm wrong as you have a greater understand of such matters
> Whoops!!! I typed that yesterday
> I need another sticky on the screen to say "click on post reply"


Hi Ian
I would be absolutely ecstatic if I could approach things in this way!
Currently though, other raw converters and imaging software do not necessarily support DNG!
And this is the key!

For DNG to be a fully functioning archival raw format it needs to be universally supported - like JPEG and TIFF formats are now.
I believe that the time will come but it hasn't yet....
I cannot convert all my images to DNG currently because I may not be using an Adobe product in the future!
I don't want to change but Adobe is going down a path that I may find I cannot follow.
Right now, where every product that Adobe makes becomes unavailable to me, if I had already converted to DNG I would be more than a bit stuck.
Even if I had used the option that allows me to save the proprietary raw file inside the DNG, I would still be left needing to extract all those proprietary raw files again.

I am looking forward to the day when either every camera uses DNG as it raw format and /or converting to DNG is the only sensible course of action both in the short term and for archival purposes....

Tony Jay


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## tspear (Apr 10, 2018)

Hoggy said:


> is the Tiling aspect.  DNG conversion makes DNG's in a tiled fashion, to make better user of multiple CPU-cores.



That is cool. I did not know that. I wonder if any raw formats can be analyzed in the same way; or if the tile aspect of DNG is designed for a specific number of cores...

Tim


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## Hoggy (Apr 11, 2018)

tspear said:


> I wonder if any raw formats can be analyzed in the same way; or if the tile aspect of DNG is designed for a specific number of cores...



The 1st part I don't know.  But now you got me wondering more about the 2nd part - especially seeing as I'm about to go from a humble circa 2012 4-core laptop, to a massively spec'd 16/32-core monster-beast. 

I've been trying to do some google searches, but not coming across anything more specific yet.  I came across a reference to "tile" in the spec, but that tends to be a bit over my head.

Do any other DNG aficionados know more about the details?


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