DNG vs NEF

[Manfred M]

Thank you for posting this Molly...

There is a lot of information to digest here, and I wonder if someone could simply answer if there is any need to convert one's raw files to DNG files? I ask because I was reading in my Adobe Elements book that raw files might become obsolete one day, and that is the reason that DNG files were created...

I have enough on my plate (and in my computer memory) with raw and jpeg files... So if I never convert my photos to DNG is that alright? Or will the day come that raw files are obsolete and the loss of all my raw photos because no program can work with raw files anymore?

That is certainly one of the arguments that Adobe put forth when they put out the DNG format, but there is no guarantee that Adobe will continue to support that format either, especially given that very few camera companies have taken it up. It too is a proprietary format, and if Adobe ever changes the licence conditions, it could become obsolete overnight as well.

There are other RAW converters out there too, so frankly it is not something I am going to worry about. I've tried the DNG files and have stopped using them, as for me they have more downsides (you have to use the Adobe RAW engine), than upsides. If I were truly concerned, I would convert all of my files to 16-bit TIFF files.

[FrankMi]

Hi Christina, I convert all of my RAW images to DNG but not because I am overly worried that 10 years from now I might not be able to reprocess one of today's images. I use DNG because I do all my post processing in Adobe software and DNG is the easiest common format for me to use.

There are many combinations of products and processing workflows so whatever works best for you is going to serve you well provided you take the time and effort to learn it well. If, in the future, you want to change workflow or products it is fairly easy to do as many of the post processing workflow basics should remain fairly consistent.

As you can determine by the responses, folks can become comfortable with a wide variety of different applications and processing workflows for a number of different reasons and still turn out some outstanding images.

At this point in your photography journey, I wouldn’t become overly concerned that folks use totally different approaches to achieve the same basic results. Over time, you will develop your own favorite applications and techniques that apply to your style of photography.

[Brownbear]

Dear Manfred and Frank,
Thank you to both of you for your replies and clarification. Very helpful..
Christina

[photomy]

One thing I have not seen anyone here mention re the NEF or DNG is what Adobe calls a "sidecar" file. When I take my NEF's and process them in Camera Raw, Adobe has to store all the information about how that file was processed. If you leave your images as NEF Adobe writes a file that has to be stored with that NEF - this is a sidecar file. When you convert your images to a DNG (which you can do at download if you want) Adobe incorporates all that info in the DNG file, thus eliminating the need for the sidecar file. The advantage is two fold. If I process a NEF and then want to send that Raw file to someone else with all the information about how it was processed, the sidecar file must go with it - otherwise the person you are sending it to will not be able to view the processed image. Of course this does not apply if you are not sending the Raw file. With the DNG format all the information is in one package, so you don't have to worry about making sure the sidecar file is exported also. As to quality and processing, I have not been able to tell the difference. I have processed my files in both formats and can't tell the difference. For me it came down to workflow and simplicity. I am not going to use Nikon's image processing software (I have tried it) - learn their system, save in TIFF, and then take that shot into Photoshop CS6 to do some additional work or use some filters etc. As far as I can see, Adobe is the way to go, and I now convert my files to DNG when I download them. That's my 2 cents, and probably only worth about that!

One thing that I find a bit strange about DNG files, is that when you edit them in LR you have to remember to manually go into one of the menus and instruct LR to create a new embedded preview JPEG that shows your edits in the case of external viewers or editors (Photo Mechanic, Fastone, Windows Explorer, IMatch, etc.). There is not even a reminder when you leave the Develop module or an option to do this automatically.

[Manfred M]

And of course. two pieces of software that I use frequently; Nikon ViewNX2 (and Capture NX2 as well I suspect) and DxO can only open RAW, not DNG files.

[Hero]

Some food for thought I stumbled upon the other day: http://www.bythom.com/dng.htm

[wobert]

I had a look at Hero's "bythom" link, but have two comments to add-
1) His assertion that "RAW images don't look like that rendered in the camera" was written in 2001?- Lightroom 4 (& possibly version3) allows for choosing specific camera profiles that will render the image monitor view the same as the camera. And profiles can be edited and saved as a preset to render your RAW images on screen just as you want them for a starting point to post-processing.
2) Adobe's "Planned obsolescence" has made my 'CS5 Camera Raw' incapable of reading my new Canon CR2 RAW images! My favored work-around is to use the Adobe DNG Converter and convert the images before importing into Lightroom-3.
I have no intention of upgrading Photoshop just yet, (or using the Canon software) and I have even been able to edit DNG images with PS-Elements V6! (now up to v11)

My simplistic understanding of DNG is that only the metadata in the proprietary (NEF CR2 etc) file is re-arranged by 'Adobe DNG converter' into the open-source standard,-the image data remains the same. Every new camera seems to have with it a new variety of its' RAW file, making software upgrades an annoying necessity unless you use DNG.

My first post on Cambridge! Love the site and the forums.
Cheers

[revi]

I had a look at Hero's "bythom" link, but have two comments to add-
1) His assertion that "RAW images don't look like that rendered in the camera" was written in 2001?- Lightroom 4 (& possibly version3) allows for choosing specific camera profiles that will render the image monitor view the same as the camera. And profiles can be edited and saved as a preset to render your RAW images on screen just as you want them for a starting point to post-processing.

The article is marked as being posted in 2010 (right below the subtitle). And his argument might still be valid, unless Adobe gets camera-specific information directly from the camera makers. If not, the profiles Lightroom uses are also produced by reverse engineering, and not neccesarily the same as the in-camera profiles. Not saying that that's a problem, just that Hogan's assertion still stands in that case. (there's more to raw conversion than just colour profiles, there's also the interpolation routine to decode the RAW sensor data)

2) Adobe's "Planned obsolescence" has made my 'CS5 Camera Raw' incapable of reading my new Canon CR2 RAW images! My favored work-around is to use the Adobe DNG Converter and convert the images before importing into Lightroom-3.
I have no intention of upgrading Photoshop just yet, (or using the Canon software) and I have even been able to edit DNG images with PS-Elements V6! (now up to v11)

Well, Adobe can't know in advance what camera makers are going to do to their raw formats for a new camera, so not sure that that can be called 'planned obsolescence'... Didn't you have to upgrade the DNG converter to take into account the new format?

My simplistic understanding of DNG is that only the metadata in the proprietary (NEF CR2 etc) file is re-arranged by 'Adobe DNG converter' into the open-source standard,-the image data remains the same. Every new camera seems to have with it a new variety of its' RAW file, making software upgrades an annoying necessity unless you use DNG.
(...)

See above concerning a need to upgrade the DNG converter...

And, as long as camera makers change formats regularly (justified or not, given that possibilities increase as well), you'll probably have to update your software when you change camera. Although I admit it's cheaper to upgrade a free program like DNG converter than the likes of photoshop.

For me personally, DNG isn't particularly useful, as the software I use is perfectly able to read my RAW files, and I would have kept those in any case. And there are some patents involved with the DNG specification. Seeing what's happening with patents and Android at the moment, that makes me a bit reluctant to become dependent on DNG.

There's one use I have for DNG, and that's the generation of a camera profile from a shot of the colour passport standard colour chart when I need high colour accuracy.

[wobert]

An excellent reply Revi.
Perhaps in hindsight I should have said- Camera Manufacturers' "Planned obsolescence" or maybe "Advancements".
And yes I do concede I have upgraded DNG Converter, but by doing so I didn't have to spend over $1000 for PS-CS6 upgrade. (Australian prices for software are sometimes much greater than overseas!) I do like Lightroom, and will be upgrading that for sure!
I would like to applaud your mention of the DNG Profile Editor- How good is that -you can photograph a Macbeth colour chart and create a profile specific to your camera.
Got to admit- Digital is getting better all the time.
Thanks for your comments.

[revi]

Ty

Actually it was Colin Southern who first mentioned using the Colour passport with DNG software to generate a camera profile. He'll correct me if/when I'm wrong, but iirc he uses that sometimes on a per shoot basis (i.e. set up the lights, take a shot of the card, generate a profile and use it for the that specific shoot).

[PeteC]

Ah me what a minefield. Personally I do not think one can talk about obsolescence on its own, one’s thoughts have to take into account one’s current software technology and workflow methods. Obsolescence in this context really is about protecting one’s archive of images and whilst one’s short and medium term actions are really guided/constrained by the software technology being used, yes one should have a longer term strategy for managing one’s archive and keep a weather eye on the subject.

The simple answer to me is that in terms of managing obsolescence there is no compelling need today to move to DNG. What one should do is to keep an eye on the subject and every one or two years sit down and think it through again in terms of where you are in terms of your image evolution and what has changed in the market place since your last review.

It is certainly my experience that the difference in file sizes between RAW and DNG is insignificant; I would be far more concerned about a large percentage of TIF files in my library (currently about 500gb) where the increase in file size over Nikon RAW is about six-fold. Even then terabytes of storage are really cheap now compared with 3 or 4 years ago.

To answer Christina’s question directly – yes your RAW files will become obsolete. Of course you may not be here when that happens but then again what about your descendants access to your images.

As an aside an earlier poster said it was only hardware that became obsolescent – sorry but not true; application software, operating systems, file formats become obsolescent. Four or five years back I had to loose 6 years worth of personal accounting transactions because of this. Yes I could have kept an old computer with Win98 running just for that application but jeez is it worth it. One day that computer would have irrevocably failed.

What I learned from that episode is that no matter what the data is, always make sure your software can export it to another well known format so that you have a get out clause.

One get out clause currently for RAW files, at least the Nikon NEF files, is TIF, albeit with data storage implications. I would not be surprised in the longer term if DNG surpassed TIF. I read recently that Adobe submitted its DNG spec. to the ISO body as part of some changes proposed to TIF.

No change is easy so contrary to what I have said I guess there is a case for the earlier the move the better. Over the past week I have been evaluating Lightroom 4 with a view to moving to Lightroom and at the same time converting to DNG but I have given up. Firstly because LR does not import Nikon RAW files correctly if they have been modified and secondly whilst it has some nice features, in my view when it comes to just enhancing the image it is not as good as or as easy to work with as Nikon Capture NX2.

So right now it is clearly for me not the better option and I will not loose any sleep today over not converting to DNG. Should Nikon ultimately support DNG then I will look again.

As a final comment on the minefield, an earlier poster made the point that DNG had not been a total success in terms of adoption, especially amongst camera manufacturers and did DNG indeed have longevity. His/her observation and question are totally valid- would you today bet your house on DNG becoming the master of all; I suspect not.

The hi-fi industry has a similar turmoil but with the resurgence of the vinyl album I suspect you will not get much help from there

[revi]

Just to note that you cannot compare DNG and TIFF as if they are equivalent. One cannot replace the other.

DNG is a raw format, storing sensor data with no indications about colour space, etc. One specific thing here is that
there's only one colour channel per pixel (be it red, green or blue) and the arrangement of the different colours has
to be specified in the metadata. (of course, the embedded jpeg is a full 3 channel image with implied or explicit
colour space, but that's an addon, it's 1/4 size only)

TIFF has full colour data per pixel, that means three (or four) channels/pixel. There also can be a colour space assigned
or implied. That means that it's fully defined and can be displayed in an unambiguous way.

That difference also explains (part of) the difference in file size: 12 bits/channel, 1 channel/pixel for raw/DNG vs.
8 or 16 bits/channel, 3 or 4 channels/pixel. That's 12 bit/pixel for raw, 24-64 bits/pixel for TIFF. Also, the TIFF can be
multilayer and is a lot more explicit in its metadata (but metadata is usually not that much).

(and if you are really concerned about accessibility of your raw files, store a copy of the current dcraw source with
them; as long as you can read the media and there's a C compiler available, you can treat your raw files).