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View Full Version : Native RAW vs DNG - asking again in 2010




evilspoons
Apr 18, 2010, 04:28 PM
Sorry for the rhyme in the title (not intended) but I'm curious as to whether DNG is a good idea now in 2010. I've been searching for information on the topics but it's all from 2006-2008 and I can't find an opinion from "modern day". FWIW I'm a Lightroom 2 user and plan on going to Lightroom 3 when it shows up.

First of all - the image quality. Do I lose anything by going to DNG vs the RAW files from my Panasonic FZ8 and the CR2 files from my Canon T2i (aka 550D)? Bits per channel, in-camera parameters, etc? I know it's still better than JPG, but... I don't know if the TIFF it supposedly uses internally is "good enough".

Having lens distortion correction with would be fantastic but I don't know of any way to accomplish it other than using Canon's RAW converter and rendering out JPG files (or goofing around in Photoshop manually afterward and likely getting it wrong). I know DNG v1.3 allows for operations that would let this happen in THEORY, but has anyone actually implemented it?

Second - files. Does it save any hard disk space? My T2i generates RAW files that are on the order of 28 MB (yikes). I'm using a laptop and backing it up on a Time Capsule - 500 GB doesn't go that far when it's half full of music and now you're shooting 30 MB files instead of 6 MB!

Then there's the issue of Adobe Lightroom (using the 2.7 Release Candidate for T2i/550D support) putting sidecar XMP files besides the CR2 files. I hadn't even noticed them, but I suppose DNG files are supposed to integrate the metadata into the DNG so it can't get separated?

Opinions, thoughts? Thanks!



scaredpoet
Apr 18, 2010, 05:44 PM
Sorry for the rhyme in the title (not intended) but I'm curious as to whether DNG is a good idea now in 2010. I've been searching for information on the topics but it's all from 2006-2008 and I can't find an opinion from "modern day". FWIW I'm a Lightroom 2 user and plan on going to Lightroom 3 when it shows up.

Maybe I a little more methodical than most, but I usually store:

- The native camera RAW file
- The DNGs
- A set of already-processed TIFFs
- A set of JPGs

Basically, I'm hedging my bets. Does it take up a tons of space? Heck yeah. But store is cheap now, and I prefer not to take chances.

Even so and having said that, if I was forced to choose between keeping the RAW and keeping the DNG, I'd go with the DNG.

Why? Because DNG is more of a known quantity than RAW formats are. RAWs change not just from brand to brand, but model to model as well. I've shot from at least 5 different models of Canon EOS dSLR, and they each produce differently structured RAW files. Yet, they all carry the .CR2 file extension.

If however, I convert them all to DNG, I at least know that they're more standardized and better recognized by more software packages than the individual CR2s, and I don't have to be *as* concerned about what might happen if I need to work on these files on someone else's editing software, and it might balk because it'll read my 5D and 50D CR2s, but maybe not those from my 500D or 550D.

First of all - the image quality. Do I lose anything by going to DNG vs the RAW files from my Panasonic FZ8 and the CR2 files from my Canon T2i (aka 550D)?

Except in very isolated cases, no, you won't.

The one "isolated case" that I know of is a situation where a camera manufacturer was doing something specific to their camera raw format to compensate for a known issue with a fixed lens on one of their bridge cameras But even now, Adobe photoshop and related software can acknolwedge, make use of and store lens correction parameters.

In any case, the Canon T2i and Panasonic FZ8 aren't doing anything special in their camera RAW formats that will cause you to miss out if saving to DNG.

Bits per channel, in-camera parameters, etc? I know it's still better than JPG, but... I don't know if the TIFF it supposedly uses internally is "good enough".

While based off the TIFF format, a DNG is more than just a TIFF, and yes, it's "good enough."


Having lens distortion correction with would be fantastic

And you can have it in Adobe with DNG (http://tv.adobe.com/watch/cs5-production-premium-feature-tour/automated-lens-correction/).

It exists for Adobe CS4 (http://help.adobe.com/en_US/Photoshop/11.0/WSF65FB40F-00F5-445a-BD9A-38B3737A9A19a.html) as well as CS3 (http://livedocs.adobe.com/en_US/Photoshop/10.0/help.html?content=WSF65FB40F-00F5-445a-BD9A-38B3737A9A19.html).

Second - files. Does it save any hard disk space? My T2i generates RAW files that are on the order of 28 MB (yikes). I'm using a laptop and backing it up on a Time Capsule - 500 GB doesn't go that far when it's half full of music and now you're shooting 30 MB files instead of 6 MB!

That's the price you pay for 18 megapixels.

DNG can give you losssless image compression if you configure Lightroom or Camera RAW to do that. This MAY give you smaller image files. However, if you choose the option to embed the original RAW into the DNG, you'll get even larger files instead.

In any case, regardless of whether you go DNG or RAW, you're probably going to want to look into upgrading your hard drive storage soon. For me, my laptop serves as temporary storage and as a quick and dirty platform to do immediate digital processing and distribution if it's needed. But the permanent storage and my main workflow area are my home and office desktop computers. Too many things can go wrong with permanently storing them on my laptop: the hard drive can crash, or the laptop can be easily stolen (both of these have happened to me, by the way).

Then there's the issue of Adobe Lightroom (using the 2.7 Release Candidate for T2i/550D support) putting sidecar XMP files besides the CR2 files. I hadn't even noticed them, but I suppose DNG files are supposed to integrate the metadata into the DNG so it can't get separated?

Yes, the XMP metadata is embedded into the DNG. Though, I kinda like having the separate XMP files because they're human-readable with a text editor (they're just XML files).

bocomo
Apr 18, 2010, 06:04 PM
i convert all of my raw files to dng and delete the proprietary raw files

i don't like having xmp files
the lossless compression gives me smaller files than with the proprietary raw
i like the idea of the dng being an open format

John.B
Apr 19, 2010, 01:42 PM
For all the FUD about "whether your raw files will be supported in the future", Adobe owns the important parts of the patents to the DNG format (and also TIFF IIRC) and can revoke the DNG use rights (http://www.adobe.com/products/dng/license.html) to a camera manufacturer or software developer at their whim. Would they? Hard to say without a crystal ball. Likewise, what happens if Adobe ever goes under? Again, seeing in the future is difficult (no matter who is spreading the FUD).

The fact is that DNG is a "published" format, but isn't "open".

Really, in my mind, that is much more of a risk factor for second-tier camera manufacturers or software developers than for the individual photographer. (Which is probably why Canon and Nikon don't support DNG, and why most other manufacturers that do shoot to DNGs also have their own native format.)

One thing I ran into recently when I entered a judged contest was that they asked for the original, unprocessed raw file to verify whether the image had been significantly 'shopped. DNGs weren't sufficient, they wanted the .CR2 or .NEF files. They claimed some news outlets are starting to ask for the same thing from their independent PJs. YMMV.

KeithPratt
Apr 19, 2010, 03:57 PM
For all the FUD about "whether your raw files will be supported in the future", Adobe owns the important parts of the patents to the DNG format (and also TIFF IIRC) and can revoke the DNG use rights (http://www.adobe.com/products/dng/license.html) to a camera manufacturer or software developer at their whim.

The FUD is that the capacity to read CR2 or NEF files would suddenly vanish. I truly don't understand why so many people think this impotent threat is a selling point for DNG. For so many reasons this would not happen.

I'm also curious as to why so many are suspicious of the word "lossless". I guess it's the fault of people using the word incorrectly, but the word means "without loss". There's no wiggle room. Converting to DNG will leave you with identical image data. The smaller file size just comes from the data being stored in a more efficient way.

But anyway, reason I was replying was that last weekend I converted all my CR2 files to DNG. The motivating factor was that I didn't like the sidecar XMP files. The slight downside I may have already run into is that the DNG-generated preview files are of poorer quality than the original CR2-generated previews. You can select small or full size previews when converting, but even set to full size the previews are poorer than I'd like. (For anyone in the know, are there any hidden options to increase quality?)

Despite the encased metadata, if you open a DNG you've meddled with in Adobe Camera RAW in, say, Apple Preview, you'll get the "as shot" image, not the one you've colour-corrected and cropped. So finding the best set-up is not just about settling on a file type but also picking a single family of software to work with. Hopefully this will change. Soon.

There aren't many reasons for keeping the same photo in multiple file types. I just keep the highest quality file (DNG) and generate JPEGs of the required photos when I need to print or e-mail.

Avery1
Jul 26, 2010, 07:26 PM
Keith -- I have basically the same question.

One point that was made in an article I read was that with the .DNG formatted file, you are going to consume significantly more backup space than with the proprietary+.xmp format.

The reason for this is that when you do incremental backups, and let's say you've touched (e.g. tagged, adjusted settings) on (100) x 20MB photos since the last backup... you're going to chew up 2GB of backup space. When using the .xmp file, only the .xmp file will have to be backed up as a 'delta' from the original backup. So, say (100) x 4K... or 4MB.

2GB vs 4MB. That is a significant influence to my choice.

In my case, I have about 70GB of RAW photos. I maintain 3 backups. I am going through and tagging those photos now, so I will consume ~210GB of extra backup space.

If this isn't how it works -- I'd be interested to hear that, too,

Ruahrc
Jul 27, 2010, 01:01 AM
I don't see any real reason why DNG is superior than native formats right now. The only "gain" I see is in getting rid of sidecar files, but even in my native RAW workflow I don't have any of those. All my edit data is saved in my Lightroom catalog (which gets backed up weekly) so even then the gain is minimal. I guess if I ever worked on my pictures on someone else's computer I would need to export a sidecar to go along with my RAW, but it is not something I do so it does not affect me.

Everything else (compatibility, edits, distortion correction, etc) can all be accomplished with existing software using CR2 or NEF file formats. Unless I am missing something there does not seem to be any technical advantage to using DNG whatsoever.

And I too don't understand people's fear of losing support for NEF/CR2. If Canon or Nikon pulled support on CR2/NEF, and did not provide a way to either convert your existing files to a new standard or build in backwards compatibility, they would lose customers faster than a colander loses water. For professionals, their library of images is literally their livelihood- for a professional imaging company to pull support on their file format with no recourse is probably the 100% surest way to guarantee that you go out of business within a year.

Avery1
Jul 27, 2010, 10:25 AM
I don't see any real reason why DNG is superior than native formats right now.

One example that I have from within the last week is that I downloaded some geocoding software that is supposed to support the panasonic .RW2 format -- a bit of a second-tier format, based on user population. The software works with my .NEF files, but not with the .RW2 files for my camera... it gives a file format error. It's pretty challenging for every third party manufacturer to test each and every camera's format -- so in actuality they don't get tested thoroughly. However, you can bet that most of them WILL test the .DNG format very thoroughly.

And I too don't understand people's fear of losing support for NEF/CR2. If Canon or Nikon pulled support on CR2/NEF, and did not provide a way to either convert your existing files to a new standard or build in backwards compatibility, they would lose customers faster than a colander loses water. For professionals, their library of images is literally their livelihood- for a professional imaging company to pull support on their file format with no recourse is probably the 100% surest way to guarantee that you go out of business within a year.

A CR2 isn't a CR2 and a NEF isn't a NEF. Almost each camera has a unique format, and they all happen to have the same extension. I think Nikon and Cannon have about 30 raw formats, each. The reality is that 20 years from now, the top 10 cameras of today might still be supported by the native manufacturer's software, but the chances of them supporting all prior cameras or third parties supporting all older models isn't realistic. It just isn't costworthy to maintain all that code for 20 year old cameras.

Anyhow, I've chosen to try out DNG for a while, but am bummed about the fact my backups will be larger. However, disk gets cheaper at a faster rate than photos are getting bigger.

Ruahrc
Jul 27, 2010, 11:57 AM
The software works with my .NEF files, but not with the .RW2 files for my camera... it gives a file format error.

You may have a point when it comes to these second-tier proprietary RAW formats. As a Nikon shooter I didn't think about that aspect. DNG might make more sense in those cases.

A CR2 isn't a CR2 and a NEF isn't a NEF. Almost each camera has a unique format, and they all happen to have the same extension. I think Nikon and Cannon have about 30 raw formats, each.

Without knowing more technical details of how each CR2/NEF version is different, it is hard to say how different each iteration of CR2 is. It could be that they are very similar (data structure is the same, just some changed header info that RAW software needs a small update to be able to understand) or that they are optimizing along each step of the way.

Ruahrc

John.B
Jul 27, 2010, 02:14 PM
The party that stands to gain the most from DNG adoption is Adobe. That was true the first time around and it's still true today.