What are the advantages of shooting in a proprietary RAW format over DNG?

Question

Personally, I shoot in DNG and avoid the proprietary RAW format for my camera (PEF on a Pentax K200D). I like DNG because it's open and supports embedded metadata, both of which is not true with formats like PEF (Pentax), NEF (Nikon) and CRW (Canon). What are the incentives for shooting in these proprietary formats then?

Clarification: My question is not really about converting the RAW format of the camera into DNG as a part of a workflow (during post processing or importing, say) but rather if the camera supports shooting both RAW and DNG then why stick with RAW.

Answer 1

There is something particularly conceptually wrong with throwing away the stuff that comes out of your camera. If your camera shoots in DNG, then that's what you work with. If it shoots in RAW, the same. If it shoots in either, you have to figure out what the difference is in terms of metadata that is supported, as well as all of your workflow.

When your camera shoots in its own proprietary RAW format, and you convert that into DNG and throw away the former, you're essentially throwing something away and the sad part is that you probably don't even know what. It's like shooting in color negative film, and have the lab contact print that into color positive film, just because you're scared that someday your scanner will no longer scan negative film anymore.

If your workflow supports your proprietary format today, there is no reason to think that it won't support it tomorrow. So what is the net benefit of converting it into another proprietary format that is simply 'open' because Adobe has published the specs? That whole open/closed thing doesn't matter. What matters is the tools that you use and how they support them.

I've made the mistake of converting and throwing away the originals, and I did learn the hard way. I didn't lose any shots, but I lost my freedom to use them in the tools that I wanted, because those tools didn't support the DNG as much as I wanted to.

Answer 2

I guess technically speaking, DNG (although it is called a raw file or raw file archive) is not really raw in the truest sense. A "RAW" file is one that is essentially a direct dump of data from a camera's image sensor and image processors (i.e. Digic 4 in Canon), without any format conversion or processing applied. Such raw files are tuned to the hardware for optimal performance, and as such are unique to the hardware they are written by. Thats why each camera manufacturer has their own format. Saving to DNG within a camera would require conversion from the cameras native raw file format into DNG.

The advantages of a true RAW format over a DNG are probably limited. If you photograph action a lot, and use a high frame rate camera like Canon 1D series or the Nikon D3 series, shooting in the camera's native raw format will likely get you a higher FPS vs. shooting in DNG (if it is supported), since you eliminate the need to convert. If a high frame rate is not important, shooting directly to DNG is probably beneficial as it can shorten your import times for post processing.

Answer 3

The biggest advantage to me, is that it's an extra step in my workflow to convert my 5D2 raw files to DNG. That extra step translates into more time in the post processing step. I'm going through 20GB of photos I just took while in spain, and converting them to DNG before I got started with it, would be a pain. I could save the resultant images as DNG, or have Lightroom convert to DNG upon import, but that still is more time that doesn't translate into any percieved benefit (since Lightroom already manages the metadata for me).

If my camera could shoot DNG natively, then perhaps I would consider shooting DNG.

Answer 4

There's one particular difference that I'm aware of: proprietary RAW formats contain complete data, while the DNG standard has a specific format, which may not match up to a RAW format. I'm aware some vendors, Nikon in particular, have been encrypting some of their RAW data so that it cannot easily be converted, if at all.

As requested, I found a source from my bookmarks regarding the encryption issue. Following is a quote from a forum posting I'm unable to find at the moment. Text is copied from http://www.photoshopnews.com/2005/04/17/nikon-d2x-white-balance-encryption/:

They (Nikon) decided to ENCRYPT the white balance data inside the NEF file for these cameras. Previously, the white balance data was stored in non-encrypted format, and was readable to third party raw converters using simple reverse engineering of the file format.

Referring to the D2X and D2Hs; the blog post is from April 2005, for what it's worth. It may have since changed - haven't been following the issue, I just use NEF - but it was a concern at the time.

Answer 5

Another advantage is that the manufacturer's raw files are better supported by post-processing software. For example, the raw converter I use, Bibble, supports basically all Nikon DSLRs and add support for new models quickly. The way they do this is to obtain raw files from each camera and test those and tweak as necessary. This is done using NEF, not DNG. Thus, for any given camera, the data flow from sensor to JPEG is better tested if it does not include DNG.

Answer 6

Losing the manufacturer-native RAW file feels akin to throwing away negatives just because you have some prints (okay, it's not that bad).

It seems logical that camera manufacturers are in a position know their cameras, their lenses, their systems, best. Though DNG is extensible, it's not controlled by camera manufacturers, and innovations they implement may conceivably not be easily reflected in DNG. They could, on the other hand, more easily extend their own RAW format(s). On the other hand, if they were constrained by DNG, it could conceivably stifle innovation. Is DNG always good enough for everything? Or is DNG just better for Adobe?

What if DNG becomes a standard and needs to be extended to support a new feature Canon rolls out, but Nikon has more sway with the standards board? Or maybe Canon wants to keep it proprietary? DNG breaks down and everyone's using their own formats again, and DNG. You'd have been better off just using a camera-native RAW format all along.

As for workflow, i'd support conversion to DNG if it makes software better, but if my Nikon saves its best image as NEF, you can be sure i'm saving that NEF file, even if i convert to DNG. If my next Nikon spits out DNG files, i will only opt for that if i can't get a NEF from it.

If your Pentax does both, i'd stick with the PEF file. If you use DNG in your workflow and have card space to burn and you'd rather have the camera do the DNG conversion in-camera, take advantage of that and save both. But throw away the PEF file? No way. What if your next Pentax doesn't save DNG? What if DNG eventually goes away? Will you some day kick yourself for not having that PEF?

Answer 7

Since my other answer (while popular) is not really an answer to the question, I'll go ahead and post the right answer.

If your camera shoots in DNG 'natively', then I would go ahead and go with DNG, because it's what the manufacturer adopted as its 'raw' format. It will contain every bit of information the camera can produce. I believe that this is what Leica is doing, but I'm not sure.

If your camera offers both DNG and their own 'proprietary' RAW format, then I'd consider using the proprietary format if your workflow allows it. In my case, if LR would support the raw format I'd use that. You have to wonder what advantage the camera manufacturer saw in supporting its own proprietary format in addition to DNG and my suspicion would be that it couldn't contain all the bits of information they wanted or in a format they wanted or the software just omitted some bits out of lack of time to implement it.

If you're worried that your proprietary format may one day be no longer readable, convert to DNG but for the love of god and all that is holy do not throw away the originals.

Answer 8

Whether there is any benefit of shooting in the proprietary format depends on the particular implementation of the two raw formats by the manufacturer. For example, is the DNG format storing the same metadata? Is it using lossless compression? If the files give identical results and contain identical metadata, then it might be beneficial (more future proof) to shoot DNG in camera.

That having said, one of my cameras shoots DNG only. When importing to Lightroom, I still let it "convert" to DNG. When the file is processed this way, LR adds fast load data and some other information that makes it easier to edit the files. So in my case the workflow and processing time is the same as with camera that stores only proprietary format.

To sum it up, I would compare the outputs for quality and metadata. If there is no difference, I would shoot DNG. If there is difference, I would shoot the format that gives better results and makes the camera more happy. I would convert to DNG in Lightroom anyways. My workflow is based on LR, YMMV.

Answer 9

Note: For your particular case where your camera actually shoots in DNG there's no reason not to use it as that IS the RAW format of your camera anyway. Note the definition of DNG is Digital Negative (DNG): an open lossless raw image format. That is, DNG is also a RAW format.

While there're very strong arguments about DNG VS RAW let me summarize a couple of things from the practical point of view:

DNG is a better format 99% of the time. Original RAW is only important if you are using propietary editing tools (like nikon capture nx 2, for example) or if you're going to participate in a contest (or forsee that you may) that requires you to provide the original RAW. Even in those cases I would recomend using DNG with the original RAW embedded in the DNG.

What we sometimes forget is that the RAW image is not the final image, the only value it really has is to provide authenticity to the photo if that is required. The RAW file is equivalent to the negative, you have to develop it for it to have real value. What has value are the final images that you can extract from that RAW file, and for that I've never been able to notice any difference between developing the file from RAW or from transformed DNG.

Against what is usually believed, DNG is not an Adobe format, is an open RAW format created by Adobe, but it's open, which means the information about the format is available to everyone, unlike propietary formats which are usually revered engineer.

This has a couple of implications:

1. If you're using independent software (i.e. not your camera manufacturer software) they're doing a conversion anyway from the original RAW to something they can understand. As far as I know none (or at least not the most used programs) work directly with RAWs, they interpret the information and then store the changes in different formats. That means if you're using Camera Raw or Lightroom to edit your images, working with the original RAW posts no benefits.
2. When you transform your RAW to DNG some information is lost, however, once again, if you're using some of the most used comercial tools (basically anything that is not your camera manufacturer software), the information that is thrown away anyway is information that can't be used by the software in any case... and the information that is thrown away is never part of the information that conforms the image.
3. Some photography contests require you to provide the original RAW file and DNGs are not valid unless that's the native format of your camera. That's a point to take into account and if you feel a photo may be contest worthy you should emb the original RAW into the DNG.
4. DNGs are smaller, which translate in less space used and faster load times in most programs.
5. There's the theoretical possibility that some of the information of your RAW that Photoshop doesn't understand today, turns out to be used in a future version of Photoshop and by converting it to DNG you lose it. This is a really slight possibility.