Converting to DNG: What are we losing?

<p>Hi.</p>

<p>So, I've been debating whether or not to convert my CR2 files into Adobe's DNG. I have so many good use for DNGs. I personally think the idea is great! Being able to search by keywords on all my photos, from all drives, etc directly from Windows or Mac's search. Being able to save all my mods directly in the DNG (and sending these overs across countries without the need of sidecars xmp or my LR catalog), etc. etc.</p>

<p>There's just one thing I'd like to know: do we lose image quality when converting to DNG? I mean, Just look at the file sizes of a converted image! No, I ain't doing any lossy compression or anything. ALL my converted CR2 becomes smaller in filesize after converting.</p>

<p>What am I losing here!? If anything, shouldn't my file be bigger... having the Embed Fast Load Data on also?</p>

<p>Thanks. Patrick</p>

<p>The one thing you lose with the conversion to DNG is the option to work with these files with the manufacturers software. Some proprietary metadata may or may not be preserved/accessible (active AF sensor ...)<br>

Regarding the file size: If your original files have no compression at all you'll already get significantly smaller files with lossless compression (as used in standard DNG). You can try to zip one of your original files and see how much smaller it gets.</p>

<p>Andreas, but this is what I am saying: I <strong>do not</strong> use lossless compression. The "Use Lossy Compression" remains <strong>unchecked</strong> in the DNG converter. That's true for both, my settings using Adobe's DNG converter, and Adobe Lightroom. So, I should have NO compression done.</p>

<p>Surely, I am not the only one wondering what's missing here seeing my file size decrease.</p>

<p>I personnaly know of some photographers that WONT convert to DNG just because of this "unclear" thing going on.</p>

<p>And if we talk about the lost of proprietary metadata.... Anyone has any examples of this?? Like what? Should I care? How can this affect us? <br>

</p>

<p>> Andreas, but this is what I am saying<br>

I read what you said; please do the same.<br>

> I <strong>do not</strong> use lossless compression.<br>

Yes you do.<br>

> The "Use Lossy Compression" remains <strong>unchecked</strong> in the DNG converter.<br>

That's why the compression is loss<strong>less</strong>, as in "not lossy".</p>

<p>Okay. Sorry.. I'm french and I guess I've mistakenly mixed the words "lossy / lossless". Apologize for my misuse. </p>

<p>So, can you clarify...<br>

DNG, <strong>no matter what</strong>, has a minimum compression being done. This being called "lossless"? And there is no data lost possible with this technique? (as it appears by googling).</p>

<p>IF I were to check that checkbox "Use Lossy Compression", THEN I would potentially lose some quality. <br>

<br>

So, my files bit count would be smaller because of a) there IS a minimum of lossless compression being done in DNG, and b) because some proprietary metadata is lost. <br>

<br>

Is this correct? I'm getting this right? I'd still like to understand what is this proprietary metadata lost... as in should I care about that?<br>

<br>

For anyone else reading this post and confused with lossless vs Lossy:<br>

http://www.maximumcompression.com/lossless_vs_lossy.php</p>

<p> </p>

<p>From where I stand, concers here mentioned are purely theoretical. As long as one preserves the original file, either on the memory card or as a copy, there's nothing to worry about. When in doubt I process the same image several times; once in the camera maker's sw, once in LR and/or in PhShp. The latter could be DXO or Capture One. There may be others like SilkyPix.</p>

<p>"What am I losing here!?"<br>

<br>

Lots of info and choices. You can't possibly know what software you will want to use in the future. DNG conversion has lost its popularity as it never became the industry standard we hoped it to be. </p>

<p>You loose time and harddisk space. Advantages are insignificant since I'm using Lightroom for organising pictures. All in all I don't see many advantages for DNG. Perhaps for storing Canon CHDK raw's -if possible but in that case TIFF's will do as well.</p>

<p>How am I losing HD space? My files are smaller in size after converting to DNG, thus my hole questioning about what I am losing. Time however perhaps. The time to convert them...</p>

<p>@Eric: well there's something I don't get with people regarding this. You are talking about some kind of dependancy to Adobe, right? By all means do counter-ague me afterwards but... people say things like they dont want to be stuck with a software like Adobe PS or something to edit, having proprietary file formats and all. Isn't just keeping your Camera RAW files the same!?? You'll STILL need to open them with your camera manufacturer's proprietary software, or wait intul another application starts supporting that file format....</p>

<p>I think whether you use CR2s or DNGs, the dependency problem will remain the same. Really. That's what I think. </p>

<p>My apologize if I got it all wrong and didn't properly understand what you were saying lol :)</p>

<p>Pat</p>

Well, perhaps you want to save the original files as well. In that case it takes extra disk space. As far as I know Adobe's

DNG converter will let you save the original RAW's as well, inside the DNG file.

Dependency on Canon or Adobe - i don't think it matters much. Either may decide to drop support of their proprietary

format some time in the (far?) future. Not too much of a problem now. If it happens you can choose the next format , be it

TIFF, JPG, DNG, CR2 or another.

<p>Converting to DNG doesn't lock you <em>into</em> an Adobe workflow - it does lock you <em>out</em> of the manufacturer's software, however. Lightroom and pretty much all other converters not provided by a camera maker will take pretty much all file formats, including DNG and proprietary formats. As of today the camera makers' software typically only supports their own proprietary format, and <em>not</em> DNG (with the exception of those who use DNG in their cameras, of course).</p>

<p>There are lots of strong opinions on the DNG vs RAW question and I wrestle with it fairly regularly. Here are my thoughts:</p>

<p>- Incompatible with Camera manufacturer's software - insignificant to me. I use Lightroom and I thought Canon's DPP was pretty goofy.</p>

<p>- Format may not be supported in the future - insignificant to me. I can't see how anyone can predict that DNG will die before CR2 or NEF dies. If it does, there will be a way to convert DNG to whatever format takes its place. And if there is no conversion software, I'll write it and get rich.</p>

<p>- Faster, lighter, more powerful - kinda significant. XMP files are not an elegant solution to the metadata problem, but DNG is.</p>

<p>- Photo competitions - kinda significant. I don't compete, but if I start and have a great photo I would hate to be disqualified because I converted it to DNG. I'm not sure how big of a problem that is, but somebody here said it was an issue.</p>

<p>I still haven't converted to DNG, but I think about doing it all the time. I also pay attention to the expertise here on Photo.net (and post things like this to see who disagrees with me).</p>

<p>Fire away!</p>

 

<blockquote>

<p>And if we talk about the lost of proprietary metadata.... Anyone has any examples of this?? Like what? Should I care? How can this affect us?</p>

</blockquote>

<p>For instance - if you're a Nikon and NX2 user, the software can read the sets you made via menus, e.g., WB, contrast adjustment, etc., while Adobe converters will not read them all and uses Adobe's converter defaults instead.</p>

I still have not found a compelling reason to convert. And glad that I haven't looking back since DNG was

introduced.

<blockquote>

<p>So, I've been debating whether or not to convert my CR2 files into Adobe's DNG. I have so many good use for DNGs.</p>

</blockquote>

<p>Do a search on these forums, it's been discussed a lot. </p>

<blockquote>

<p>do we lose image quality when converting to DNG?</p>

</blockquote>

<p>No. The only data that isn't usable is the proprietary metadata the manufacturer's raw converter could use (which some could argue could produce better quality than "fill in the blank for raw converter"). DNG is raw data assuming you don't set the conversion preferences incorrectly. </p>

<blockquote>

<p>shouldn't my file be bigger... having the Embed Fast Load Data on also?<br /></p>

</blockquote>

<p>Not necessarily, depends on the compression used. Embed Fast Load Data speeds up the preview's you see Lightroom (Develop) and ACR. It also doesn't require you use the ACR cache system which has a size limit (it's a rolling cache). That cached data may not be in the same location as the raw therefore not accessible, the Fast Load Data is part of the DNG.</p>

<blockquote>

<p>The time to convert them...</p>

</blockquote>

<p>If you use Lightroom (as was admitted), the difference is tiny compared to the entire import process. Plus you can ask LR to write the proprietary raws to another disk <strong>at the same time. </strong>I doubt many LR users sit around looking at LR while it imports any way. </p>

<p>See these threads for some considerations regarding converting to DNG:</p>

<ul>

<li><a href="/digital-darkroom-forum/00b9mg">DNG Files Again</a></li>

<li><a href="/casual-conversations-forum/00WQjJ">Converting DNG files back to camera raw (CR2) - PLEASE HELP, Urgent.</a></li>

</ul>

<p>If you do choose to convert to DNG, it's still a good idea to archive the original camera raw, just in case you choose to submit a photo to a contest or news outlet that may require the original camera raw for verification.<br>

<br />My Ricoh GX100 uses DNG as the raw format, so that's what I use. Works okay, although Lightroom doesn't seem to recognize Ricoh's in-camera JPEG settings well enough to recreate the same looks from DNG in LR4.</p>

<p>My Nikon digicams use NEF and I don't convert to DNG. No reason to. Lightroom and most editing programs handle NEFs well enough. Nikon's own software (while annoyingly designed, to me) handles the few tricks other programs don't, such as applying in-camera JPEG settings to NEFs if desired.</p>

<p><strong>"How am I losing HD space? My files are smaller in size after converting to DNG, thus my hole questioning about what I am losing. Time however perhaps. The time to convert them..."</strong><br>

<strong> </strong><br>

Pat, everyone, including Adobe and it's apostles, suggests you keep your original raw when converting to dng. Assuming you are, you're going to need additional hdd space as you are literally doubling the amount of your files. If for example you have 2Tb of nef's and wanted to convert to dng, you'd need, at best guess, an additional 1.5Tb's of space for those dng's. Now you have 3.5TB's. I back up to more than one medium type. I burn everything to optical disk (twice) and on top that, I make two copies to external hdd's. And because hdd's that haven't been powered up for a long time have the possibility to lock up, I'm diligent and duplicate those again every couple years just to be safe. I have 12 high capacity hdd's at the moment holding my works. These 12 drives do not include the drives along the way that have have been consolidated into them. That sounds confusing. The point is, I don't even want to think back at how much time I would have saved if i didn't do the dng nonsense in the first place. Anyone that says dng speeds up your workflow, doesn't shoot very much.<br>

<br>

Or the money. I just looked at an old ide 120gb drive of mine and it has a $320 price tag lol. Also, today with cloud storage and back up, services like Crash Plan and Carbonite are able to identify the files on your system that have changed since it's last back up, and only upload those changed files to their remote server. When you open or revisit a nef, only its small xmp side car file is altered and only it is uploaded to Crashplan. This is not the case with dng as the whole dng is resent. <br>

<br>

<strong>"@Eric: well there's something I don't get with people regarding this. You are talking about some kind of dependancy to Adobe, right? By all means do counter-ague me afterwards but... people say things like they dont want to be stuck with a software like Adobe PS or something to edit, having proprietary file formats and all. Isn't just keeping your Camera RAW files the same!??"</strong></p>

<p>Dependency? No. I'm talking about choices or options. For example, today my native raw nef opens in Adobe, Nx2, and Dx0. Out of those three, my dng only opens in Adobe. Less software choices is one thing, but maybe more important is that there's a terrific amount of info in that native raw that gets thrown away. </p>

<p><strong>"I still have not found a compelling reason to convert. And glad that I haven't looking back since DNG was introduced."</strong></p>

<p>I wish I listened to you and others sooner. Instead, I swallowed the pill and started when dng was released a decade ago. I've concluded it's a complete waste of my resources.</p>

<p>Instead of "Converting to DNG: What are we losing?"... "<em>Converting to DNG: What are we gaining?</em>".<br>

I still cannot find a reason in which DNG gives me something my NEFs do not have. DNG never became the standard it was hoped to be, and while the current situation with proprietary files is far from ideal, betting on a standard with very lacklustre support from the industry it is intended for, isn't a safe bet either. The argument that somebody might pull support for the RAW file format of an older model... so far, it simply did not happen yet, as nobody has much to gain with doing so. And there is plenty open-source code already to deal with those files, so there are and will be solutions.<br>

DNG would be an excellent idea if the camera-making industry supported it properly. As it is, NEFs (and CR2 possibly as well) simply do contain more metadata than DNG, and I see no compelling reason at all to switch.</p>

<blockquote>

<p>Pat, everyone, including Adobe and it's apostles, suggests you keep your original raw when converting to dng</p>

</blockquote>

<p>I don't (and don't keep them). I see no reason. I have piles of CD's filled with proprietary files, raw and otherwise that are inaccessible unless I want to find a 12-15 year old OS and hardware that can read those files. Proprietary file formats are never a guarantee you can access your data. I've been shooting with DLSR's since one of the first (Kodak DCS-1) which at the time only spit out a TIFF. But onward, I have nearly every model of DCS camera that today can't be accessed without really old hardware and software (I did render the images I want and now they live as TIFFs, but the raws are mostly stored on drink coasters). Ditto with Live Picture iView or X-Rez proprietary file formats.</p>

<blockquote>

<p>"<em>Converting to DNG: What are we gaining?</em>".<br />I still cannot find a reason in which DNG gives me something my NEFs do not have.</p>

</blockquote>

<p>Thank you, that is an excellent question! <br /> In <strong>my case</strong> there are several items I gain:</p>

<ol>

<li>Smaller file on disk.</li>

<li>Ability to embed multiple DNG profiles. I build them and use them and want them part of the DNG container, not stored deep in my system folder. Ditto with all the metadata that has to be separate with a proprietary raw (with Adobe converters). If I move from desktop to laptop to another location machine, ALL the necessary data is in the container along with the raw. Try this: Use a custom DNG profile and make the image look as you desire. Now move the NEF or CRW to another machine. You better also move that DNG profile with the original (and side car) or you're in for a big visual surprise.</li>

<li>Embedded JPEG that shows the current rendering (if you set LR/ACR correctly). Extract it if you had an emergency. Or you just need something bigger than a tiny thumbnail preview.</li>

<li>Fast Edit Preview. I already discussed this. On my machine, the differences between initial building then loading the ACR cache for Develop vs. Fast Load is significant (nearly 1.5X faster). Of course I never have to worry about losing the ACR rolling cache data, let along if it's stored on another machine. It's <strong>part</strong> of the DNG.</li>

<li>Work with Virtual Copies in LR? Well that's again just a set of instructions that are proprietary within LR. But if you wanted a self contained raw with all the work you just did, export as DNG. That's the <strong>only</strong> option to save off a raw file but of course if you're sure you are done editing <strong>forever</strong>, save out a TIFF.</li>

</ol>

<p>ANY of the above items for ME make the chose of DNG simple. It doesn't take any more time in the grand scheme of things to convert to DNG while importing than not converting to DNG when converting. I'm just not sitting there watching the import.</p>

<p>The bigger issue is that proprietary raw (proprietary anything) is never as good for the customer rather than an open format. Kodak DCS, Kodak Photo CD image pack, iVIEW files, etc. The JPEG generated by the <strong>newest</strong> camera to hit the market <strong>can be opened</strong> in my very, very, very old copy of Photoshop 1.0.7! The <strong>newest</strong> raw from Canon may <strong>not be accessible</strong> by the last version of Photoshop CS5. How is that good for photographers? You're either part of the solution (demanding an open raw format) or you're part of the problem. <strong>Not</strong> complaining to the camera manufacture's about this, dismissing DNG instead doesn't help in solving this problem. And it's a problem.</p>

<blockquote>

<p>DNG never became the standard it was hoped to be</p>

</blockquote>

<p>Standards: This is a straw man, forget it. Is NEF or CRW a '<em>standard</em>'? By what body? What does it mean? Your NEF is a standard because your camera club recommends it or more people use it than DNG? Doesn't make it a standard. FWIW, DNG IS working on becoming a standard in terms of recognitions by a Standards Body (ISO). It's actually just a TIFF (which Adobe owns, maybe that's why it's so scary). But if it makes it or doesn't is not important. NEF or CRW is not a standard as there are dozen's upon dozen's of different NEF's and CRWs. If they were the same, the poster here who just purchased a new 6D wouldn't have any difficulty using ACR 6. Bit that CRW is different from the last CRW Canon. It should really be CRW-6d, CRW-5DMII, CRW-5D etc. Same with NEF. They are all different. So much for standards.</p>

<p><strong>IF</strong> you are only going to use the manufacturer's raw converter, you <strong>DO NOT</strong> want to convert to DNG! All you posters who only use the manufacturer's converter, raise your hand. The rest of you using say Adobe raw converters, keep the original NEF's or CRW's if you want. I've been doing this long enough to have been burned and don't see how the original proprietary format does me any good unless I suspect I'll switch to (in my case) Canon's software. About as likely as my going back to shooting film.</p>

<p>Bottom line. Like Gay marriage, if you're against it, don't marry a gay person: If you don't like DNG, don't use it. But dismissing the preferences of others, based on what they feel are the advantages of either is a personal choice most make with at least <em>some</em> thought. This isn't directed at any one person posting, only people who dismiss a format and workflow I and others find VERY useful. There's no reason to dismiss it, don't use it and move on. In terms of DNG, dismissal doesn't do much to help fellow photographers in controlling the data the camera they purchased provides. There is nothing, <strong>nothing</strong> stopping either Nikon or Canon from putting a 3rd option on the camera to write a DNG along with the JPEG or Proprietary raw. It's totally political. If everyone who purchased a DSLR demand an open raw format, we'd have one. I have no problem who marries who or what format you set your camera at. I do have an issue when I'm told I can't do something that harms no one and helps a lot of others. DNG is just such an option.</p>

<p>Andrew, thanks for balancing the discussion with clear, proper reasons to choose for DNG. While I do not share your concerns on the proprietary file formats nor your issues with my use of the word "standard" (nowhere ever did I claim NEF was a standard?), I see that in your workflow (and hence, for quite some others) there are clear advantages (and I did not mean to argue with that) I am glad the discussion shows both sides of the coin this way - it'll help other make their informed decision in what suits them best.</p>

<p>It's a shame that most of the info from the openraw.org movement is now gone and removed from the net. There's still a few little bread crumbs around though. It clearly spells out how dng isn't the "open source for profit" solution that the consumer or vendors are needing. <br>

<strong> </strong><br>

<strong>FWIW, DNG IS working on becoming a standard in terms of recognitions by a Standards Body (ISO)."</strong><br>

<br>

They been "working on it" since 2003. It's been so long, it's not even iso9000 anymore.<br>

<br>

<strong>"IF you are only going to use the manufacturer's raw converter, you DO NOT want to convert to DNG! All you posters who only use the manufacturer's converter, raise your hand."</strong><br>

<br>

How wonderful it would be if the 20 digital darkroom contributors here at PN accurately represented the real world. Most people that own dslrs simply use the included software that is bundled with their $800 kit from Costco. The reality is that only a small percentage of dslrs owners take it to the next level and purchase Adobe products. Because of this small %, there is no incentive for Nikon and Canon et al to output a dng.</p>

<blockquote>

<p>They been "working on it" since 2003. It's been so long, it's not even iso9000 anymore.</p>

</blockquote>

<p>As I said, it's a questionable and useful goal in any event. Point is, Adobe has tried to make it as open to everyone as possible. This also points out to the "<em>it's not a standard</em>" crowed how difficult and how long it takes for standards bodies to do anything. As a member of such an organization, I know too well they are usually represented by differing interests (some political), and getting anything done takes forever.</p>

<blockquote>

<p>How wonderful it would be if the 20 digital darkroom contributors here at PN accurately represented the real world.</p>

</blockquote>

<p>If <strong>every</strong> DD contributors here at PN agreed on something, it <strong>wouldn't</strong> represent the so called, undefined '<em>real world</em>'. The interesting thing about using such a term (real world) is it's so ambiguous, and anyone can say an opinion represents the real world or it doesn't. So why use some language?<br /> That said you could head over to Luminous Landscape which gets 1.1 million unique readers each month; 3.5 million page views from some 50,000 people a day, you'll certainly have the possibility to gauge a larger number of contributors. And if 25% agreed upon using DNG while 75% didn't, that would mean what in terms of the points I've outlined above (having choices, getting the manufacturer's to build something for me?). Do you have a point about the qualities of a workflow option that some prefer that in some way is just wrong and should be dismissed and avoided?</p>

<blockquote>

<p>Most people that own dslrs simply use the included software that is bundled with their $800 kit from Costco.<br /><br /> The <strong>reality</strong> is that only a small percentage of dslrs owners take it to the next level and purchase Adobe products. Because of this small %, there is no incentive for Nikon and Canon et al to output a dng.</p>

</blockquote>

<p>You can backup such metrics where? Just want to see if this is a real data point or an opinion. <br /> Let's say however this is true. The fix is education such that users WILL ask for DNG or an open raw format that fixes all this mess with proprietary raw's. Again, you're either part of the solution or part of the problem. Responsible for answering questions (the OP asked what do I lose converting to DNG) or you're part of the problem (continuing to accept the options forced on you). There is absolutely nothing to be lost by adding a 3rd option for data format on the camera and lots for <em>some</em> to be gained. If you don't want that, step out of the way please.</p>

<blockquote>

<p>I have piles of CD's filled with proprietary files, raw and otherwise that are inaccessible unless I want to find a 12-15 year old OS and hardware that can read those files.</p>

</blockquote>

<p>Andrew, check with Isobuster if they can extract those files for you. They don't use windows to do so, as far as I know. It is worth sending them an email. The program managed to extract the data from my old UDF files.</p>