Digital negatives

affleck

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30 Jan 2007 - 11:45 PM

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I got CS2 yesterday and now have a whole lot of new things to play with.

Sorry if I am missing something and this is a stupid or obvious question but......

what are the day to day advantages of converting RAW files (in my case D200 .NEF's) to .DNG's? As an amateur photographer and far as I can see there is no real advantage but perhaps someone explain if i stand to gain anything by converting my .NEF's to .DNG's.

Cheers

Gordon

Craftysnapper

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31 Jan 2007 - 7:32 AM

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I know nothing about the NEF sizes but for me the advantage is that it reduces my ORF files from my 8MP DSlr from 13.5 mb to 7mp with no loss of quality and allows me to store more on the same disc space and also allows me to embed IPTC data in the Raw file using Iveiw MediaPro3

philipr

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31 Jan 2007 - 2:19 PM

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Pretty well covered above. I also convert all my RAWs to DNGs for the future proofness and to save space.It does take a bit of time but you get used to it in your workflow .

The following is from THE DAM BOOK (pretty good book on digital workflow):

Although Adobe has named the format the Digital Negative, I prefer to think of it as a "digital job jacket." In fact, the DNG format is a wrapper
that can contain all kinds of useful information about your file. Let's take a look at what can be stored there:
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The negative
The DNG file can contain all the RAW image data that the camera puts into its own RAW file. This means that you can open a DNG
file in Camera Raw and have the full range of adjustment options that you had with the RAW file.
Paperwork
Because the DNG format is openly documented, all sorts of metadata (discussed in the next chapter) can safely be written to the file,
with no danger of it becoming unreadable or of corrupting the file.
A pretty good print
In the DNG file, you can store not only the "negative," but also a "print." Camera Raw can create a preview of the file that reflects all
the adjustments you have made. Take a look at Figure 1-11. On the left is the original embedded preview (as created by the camera).
On the right, the DNG shows up the way I've adjusted it in Camera Raw. You can correct the color, brightness, and contrast—even
crop or apply a curve—and the resulting image will be stored inside the DNG file. This embedded preview can be of several sizes,
including one that is the full dimension of the RAW file. We'll look at how this "pretty good print" can be useful in Chapter 8.

Private maker notes
If a camera manufacturer comes up with a new way to process a file, and they wish to keep the details secret, they can encrypt this
information into the DNG file. Thus, DNG files can be universally accessible, while at the same time offering manufacturers protection
for their proprietary image-processing algorithms. This will be useful as more manufacturers let users choose DNG as a RAW file
format to be produced straight out of the camera.
Undocumented maker notes
Version 3.1 of Camera Raw (and the freestanding DNG converter) will copy the undocumented maker notes to the DNG file. While
Camera Raw cannot make use of this information at the present time, it saves it for a day when camera manufacturers will embrace
DNG as a solution for file storage, or for a day when third-party software can decrypt this information. (Because this is undocumented
information, the full integrity of these maker notes is not absolutely guaranteed.)
The original RAW file
Those of you who can't bear the thought of throwing away your original RAW files can simply embed them into the DNG file itself.
You will then be able to extract this file at any later date, should you choose to. (I don't keep the original RAW files, because the DNGs
include everything I want to keep. And, of course, embedding the RAW files will make the resulting DNG files quite large.)

Beyond simply what's stored in the DNG is the issue of how it's stored. Because the DNG format is openly documented, any application that
can use DNGs can see your Camera Raw adjustments, read and use the "paperwork" you have enclosed, add more data to the paperwork, and
create a good-looking JPEG or TIFF of the file, even if it can't read the original RAW file type.
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There's another benefit to using the DNG format for image storage, too: it offers significant file-size reductions losslessly, with no loss of
quality. The compression that DNG offers (one of the "save" options) can reduce the size of an image file by up to one third. This translates
into nearly immediate savings for the photographer.
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1.5.3.2. Drawbacks of DNG
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There are a couple of drawbacks to saving files as DNGs. On balance, they are not of great concern to me, but you should be aware of them.
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RAW files saved as DNG cannot be opened by the manufacturer's software. Some people, for instance, like to use Nikon Capture for processing
their RAW files. At the moment, if you save your files as DNGs, you will not be able to open them in Nikon Capture. You could choose to
embed the RAW file into the DNG, but that makes for a pretty large archive.
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If you like the idea of embedding RAW files for certain photos but don't see the need to embed them for every image, you can use the workflow
tools I outline in Chapter 6 to embed only the RAW files for images that are rated as very high-quality photos.
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Another option is to make it known to your camera manufacturer that you would like them to support DNG. Currently, Leica and Hasselblad
both use DNG as a native RAW file format right out of the camera, and there's no reason that manufacturer's software such as Nikon Capture
cannot work with Adobe-created DNG files—they simply choose not to support DNG.
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The second drawback to using DNG is that (for most cameras) you must convert your files to this format, which requires an extra step. However,
I believe that this is well worth the hassle, given the benefit that you receive.