DNG - Is anyone using it?

[PhilipKach]

[ QUOTE ]
I have converted some images to DNG a played with it, but my concern is DNG truly lossless. Is DNG truly equal to RAW. It's my understanding that DNG is closer to a tiff image.

Or, I too have missed something.

Scott B

[/ QUOTE ]

Thanks all for providing some good information. I especially wish to thank Bruce Frazer. Your article on DNG's was very helpful. I will probably purchase your book for more insights.

Scott B brings up a question I would like answered. Is it truly equal (100%) to RAW. Unlike Scott, my understanding is that is is equal.

Thanks in advance.

Philip

[jimdunham]

[ QUOTE ]
...is anyone converting their raw files to DNG files...?

[/ QUOTE ]
Da. Ja. Oui. You bet.
Jim

[Nick_Rains]

Try pointing Bridge at a bunch of preconverted DNG files. It is much faster to preview and thumb.

My workflow involves converting to DNG as a first step using the DNG Convertor 3.1 and then using Bridge. Total time is much the same BUT, DNG files *include* sidecar files. Process a DNG file and your RAW conversion settings are stored within the DNG file, and also updated in Bridge. This is cool and makes archiving images much easier.

DNG file are in principle full RAW files in 12 bits or whatever. Plus, for the totally paranoid you can embed the original RAW file within - at the cost of increased file size.

DNG has the potential to be a killer app -if only the camera manufacturers would come to the party...

Nick Rains

[Michael_Fontana]

Just tried the newest dng, aka 3.1 in the PS-CS-1 filebrowser (the localized PS-CS-2 version isn't out yet) - and had some weird colorshifts:



when opening the file in ACR 2.4 and using the setting " as shot" they became the same.

But its not very nice to have different previews, in other - colormanaged - apps, as iVMP as well.

Any suggestions?

The CR2 hadn't been touched before. Is that colorshift gone with bridge?

[Michael_Britt]

I have recently updated and redesigned a clients archives. We ran all of his RAW file formats (Leaf, Kodak and Canon) through DNG conversion tests. We couldn't see any discernible difference in the files processed from their native formats or converted to DNG and then processed. The space savings for the Leaf MOS files was significant, over 50%.

Another benefit was that DNG files can be recognized by Extensis Portfolio where Leaf and CR2 files are not (yet). It is limited support with no orientation flag and a small thumbnail instead of a larger preview but it is allows us to catalog everything with our database software of choice.

Approximately every 5-7 years the storage media will need to be migrated to the latest and greatest format that our computers will be using. Staying current with one filetype (DNG) will be a lot less painful than making sure that each RAW camera format is still supported and accessible.

[john_Beardsworth]

Michael - Are you sure about the Orientation flag? I found that the DNG stores it in tag 274 Tiff orientation and you can map this into Portfolio.

[brucefraser]

DNG comes in three flavors depending on how you set the conversion preferences.

Compressed (lossless) is lossless wrt the pixel data. It may strip out some private metadata that is only readable by the camera vendor's proprietary converter.

Linear saves a demosaiced but otherwise unprocessed file—that's the option that's somewhat analogous to TIFF, though no tone-mapping has been carried out on the image. You can't go from a linear DNG back to a totally raw file, so it's mainly useful as an interchange format between raw converters—for example, you might want to do lens corrections with DxO's software, then do the rest of the processing with another DNG-compliant raw converter.

Embed Original Raw is absolutely 100% lossless, since it embeds the entire original raw bit-for-bit. But it makes for pretty large files, so unless you really need that obscure private metadata that gets stripped out in option 1, you're better off using option 1 instead.

The "political" point about DNG is that proprietary raw formats are a disaster waiting to happen. (Actually, in my case, they've already happened—Kodak has no software that supports the DCS 460 under any operating system created in this millenium.) Canon has orphaned D30 files. Other vendors will almost certainly discontinue support for early cameras.

DNG offers insurance against that eventuality in that, even if Adobe dries up and blows away, the DNG spec is public, and any reasonably talented programmer can use the spec to write a DNG converter (as many have already done). So my DNG files have a much greater chance of being readable 50 years hence than do my DCS 460 .tifs, my 300D .CRWs, or my 20D CR2s.