DNG ... What is it all about?

[d'homme]

I saw the download for the plug-in on Adobe's site.

[mgbeach]

It's Adobe's answer to the fact that camera manufacturers have neglected to adopt a standard RAW format. Adobe came up with the Digital Negative (DNG) format as a way to ensure that RAW files will be usable into the future. Their converter allows you to take your RAW files and confidently archive them.

[d'homme]

In the DNG format, can you still adjust them? Or is it just a way to save the uncompressed file .. universally?

[BrandonSi]

It's my understanding that with DNG there is no sidecar xmp file as well, when converting to DNG raw+sidecar all gets thrown in together.

[CyberPet]

Actually DNG does compress the files, without any loss (and you can choose to compress even more)... at least the files are a bit smaller than the "regular" Raw-files from Canon and Nikon. Also... I hope that DNG *will* in fact become the industry standard, since all those rawconverter programmers can easier make great software for us. :)

[Duder]

does anyone convert all their RAW files to DNG, and then delete the RAW's?

[tim]

does anyone convert all their RAW files to DNG, and then delete the RAW's?

Not yet, but I will in the future, I think. Also, the DNG isn't a universal answer, as I understand it the data inside is still camera specific, DNG is a container not a file format.

[CyberPet]

A friend of mine (pro photographer) does that... all shots taken with his Nikon D2x (or whatever letters there are now). He says it saves him lots of storage space. I think he's brave, but he says it works fine as long as Adobe won't do anything bad... like close down the DNG project (although I've heard that Hasselblad and some other company is adapting to DNG already with their new line of cameras).

[Barry Pearson]

Also, the DNG isn't a universal answer, as I understand it the data inside is still camera specific, DNG is a container not a file format.

DNG is a file format. And also a container!

The sensor data is camera specific. In other words, DNG still contains the Raw sensor data from your camera. (Surely this is what we want?). But ....

DNG also contains lots of other parameters that define the configuration of the sensors, and how to convert their values into a reference colour space, so that the Raw converter can turn the images into PSD, TIFF, JPEG, or whatever.

DNG evolves. At the moment it is on the 2nd version. (The 2nd version was to cater for the black masked pixels that some raw formats, mostly Canon's, store). It is "universal" for the 77 or more cameras that it supports, which include a variety of sensor types. As new sensor configurations appear, new DNG versions will be published.

DNG is an attempt to solve 2 problems that appear to be, but are not, incompatible. It must hold camera-specific Raw sensor data, because only that way can the maximum image quality be extracted by a suitable Raw converter, (which may not yet have been written!). Yet it must be processable by Raw converters that don't know anything about the camera that took the image, because at some time in the future some knowledge of cameras may have been forgotten.

So: it holds the camera-specific data; and it also holds sufficient information about the camera model that there is no unavoidable need to know anything else about the camera.

(I have no connection with Adobe, other than as a customer, but I've been using DNG for more than 8 months, and I am a fan!)

[yb98]

I was disapointed with the DNG format because in the begining I thought il was an universal format. But Last days I wanted to convert a file from a fuji S5500, so I converted it into DNG then tried to open it in Raw shooter, since Raw Shooter is supposed to be able handle DNG files. But rawshootet refused to open the file. So raw shooter handles only DNG files of certain cameras not all DNG files.

[Barry Pearson]

A friend of mine (pro photographer) does that... all shots taken with his Nikon D2x (or whatever letters there are now). He says it saves him lots of storage space. I think he's brave, but he says it works fine as long as Adobe won't do anything bad... like close down the DNG project (although I've heard that Hasselblad and some other company is adapting to DNG already with their new line of cameras).

I convert to DNG directly from the CF card, and after confirming 2 copies I reformat the card in the camera. So my PC never sees the original Raw files! They never get archived.

Adobe has gone much too far to stop DNG. ACR 3.1 in CS2 can save its settings and adjustments in the DNG file. So the result is a DNG file containing all the ORIGINAL sensor data, plus extra metadata that stores these settings, non-destructively. (Instead of XMP sidecar files). So DNG isn't just a format that Adobe promote - it is also the way that ACR 3.1 (and future versions) holds its settings between sessions. It is a working-format. Could Adobe close down "PSD" files? No - and neither could they close down DNG files.

The Leica Digital-Modul-R digital back for the R8/R9 uses DNG as its Raw format. ACR 2.4 will happily open these images.

But so will Dave Coffin's DCRaw. He is a one-man band, not employed by Adobe, who has published free C-code that will accept about 160 Raw formats, including DNG, and convert them. If Adobe and all its code disappeared, you would still be able to use Dave's software to convert your DNGs. (I keep a copy of his code on my PC!)

There appear to be an incredible number of photographers who are also C-programmers! Whatever happens to Adobe, I have complete confidence that they will provide code to handle my DNGs. (And it they don't, I'll do it myself - even though I haven't used C for nearly 15 years!)

[Barry Pearson]

I was disapointed with the DNG format because in the begining I thought il was an universal format. But Last days I wanted to convert a file from a fuji S5500, so I converted it into DNG then tried to open it in Raw shooter, since Raw Shooter is supposed to be able handle DNG files. But rawshootet refused to open the file. So raw shooter handles only DNG files of certain cameras not all DNG files.

This isn't a problem with DNG. It is because Raw shooter hasn't fully implemented DNG. RSE only supports DNG if it also supports the camera's own Raw format, and some of their documentation makes this clear.

The reason is that, while DNG files contain the color matrices that convert from the camera's colour space to the reference colour space, only ACR and DCRaw, (as far as I know), currently bother to extract and use that data. RSE relies on holding separate data about the camera.

See:
http://forum.pixmantec.com/showthreaded.php/Cat/0/Number/6413/page/0/vc/1

As a format, DNG has what you want. But only if the tools you use support it fully! That will take time. DNG is less than 9 months old. There are probably about 35 non-Adobe products that support it, but sometimes only in a limited fashion.

Have you complained to Raw shooter?

[Barry Pearson]

In the DNG format, can you still adjust them? Or is it just a way to save the uncompressed file .. universally?

DNG is a genuine Raw format. (I convert to DNG then throw away the original Raw files). You can adjust them as long as your Raw converter recognises them.

The problem at the moment is that only Adobe's ACR (from ACR 2.3 onwards) and Dave Coffin's DCRaw, unconditionally converts DNG files. In ACR 3.1 (CS2), I suspect you wouldn't even detect whether you were adjusting a DNG file or your camera's original Raw file - they appear just the same.

RSE allows DNG files to be adjusted, as long as it also supports the camera's own Raw format. That is a feature of RSE rather than DNG.

[Barry Pearson]

It's my understanding that with DNG there is no sidecar xmp file as well, when converting to DNG raw+sidecar all gets thrown in together.

Ha! Complicated.

In ACR 2.4 / CS, if you make settings to a DNG file, those settings will either be stored in the ACR database, or in XMP sidecars. ACR 2.4 can't put those XMP settings into the DNG file itself.

If you convert a folder containing your camera's Raw files + XMP sidecars, using the DNG Converter, you will end up with DNG files that have that XMP metadata embedded into them. So, yes, it "all gets thrown in together".

Ditto if you convert a folder containing DNG files plus XMP sidecars. (The DNG Converter accepts DNG files as input, of course, because they are Raw files). So this is a way of combining DNG files and XMP files that you have been processing under ACR 2.4 / CS. (By the way, ACR 2.4 / CS can READ the XMP settings from the DNG file - it just can't write them).

In ACR 3.1 / CS2, XMP sidecars are on the way out when processing DNG files. I'm not actually sure whether it is possible to continue to use sidecars when adjusting DNGs, but I certainly don't, because I want everything held in one file. So my DNGs, output after processing in ACR 3.1 / CS2, contain both the original raw sensor data, plus the same XMP metadata that would previously have been put into an XMP sidecar file.

ACR settings in the DNG file are non-destructive. For example, you can crop in ACR 3.1. But all that does it store the coordinates of the corners as metadata. It doesn't delete any sensor data. You can later delete the crop, and get you whole image back.