With the announcement of the Digital Negative Specification, Adobe is attempting to standardize how digital cameras understand image data. Will this new imaging initiative take off with camera makers? And what does it mean for you?
(creativepro.com)
By Ben Long, creativepro.com senior editor
Tuesday, October 12, 2004
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For photographers who demand maximum control and superior image quality, one of the great appeals of digital is the ability to shoot in "raw" format. Unfortunately, because "raw" is an undefined format, rather than an accepted standard, you have to have software tailored to your particular camera to access a raw file. Adobe hopes to change all that with the release of its new Digital Negative Specification.
The Raw and the Cooked
As explained in my earlier column about camera sensors, a digital camera has to do a tremendous amount of processing and calculation to turn the data collected by its image sensor into a full-color image. Raw format allows you to save all of that original, unprocessed, uncompressed data directly to your camera's media card. Through the use of special software, you can use your computer to perform all of that gnarly image processing and calculation later and with much greater control.
With raw format, you can alter your image's white balance, exposure, sharpening, noise reduction and more after shooting, as well as perform all of your usual edits in a more flexible, accurate 16-bit color space.
The downside to shooting raw is time and workflow. To even look at a raw file, you must process it through a special raw format reader. Vendors are diligent about including their own special raw software with each camera that provides raw support, but it's astonishing to see how universally bad this software is, in terms of performance, interface, and integration with existing image-editing workflows.
Fortunately, several third-party vendors have stepped in to create more usable raw solutions. However, because camera vendors usually don't publish the details of their raw specs, software developers are often forced to reverse engineer the raw format of every camera they want to support. This is the main reason that you don't see raw support in more applications.
Raw-image workflow saw its biggest boost when Adobe released its Camera Raw plug-in for Photoshop 7 (Camera Raw is now built-in to Photoshop CS). With the ability to handle raw files directly in Photoshop, raw workflow was suddenly much simpler. In addition, Adobe's raw plug-in yielded very good results (raw image data is so raw, that there can be a tremendous amount of variation in the way different pieces of software choose to interpret it).
However, the problem of varying, unpublished raw formats remains, which means that when you buy the latest camera, you may not be able to open its raw files in any software, Photoshop included.
To address this issue, Adobe has developed and published an open standard that aims to make today's raw confusion a thing of the past.
Setting the Standard
Obviously, a lot of this confusion would pass if camera makers would simply agree on a single standard for raw format files. With the release of the Digital Negative Specification, Adobe has stepped forward and offered a standard that could, if adopted, tremendously ease the development of raw-compatible software.
Based on the TIFF-EP file format, the new DNG format is controlled and maintained by Adobe (just like TIFF) but is free to be used by any developer who wants to support it. In other words, only Adobe can make changes to the format, but anyone else is free to use it.
In addition to all of the normal TIFF tags, the new specification can hold all of the raw-related information that a program needs to correctly interpret a raw file. The new spec also provides tags for all of the usual EXIF information (camera settings, etc.) as well as support for all of the same XMP metadata supported by the Adobe Creative Suite applications.
Most proprietary raw formats also include what Adobe refers to as "special sauce" information that is necessary to correctly interpret certain raw data. To facilitate this data, the DNG specification allows for camera vendors to create special "private" metadata that only they can use.
With the announcement of the spec, Adobe also released a free upgrade to the existing Camera Raw plug-in, which provides support for a slew of new cameras. In addition, they released a DNG Converter application that can convert raw files from any of the currently supported raw formats into the new DNG specification.
Who Cares? I Care!
On paper this all sounds great, but the actual benefit to end users is dependent on who ends up adopting and supporting the new format.
Right now, the only compelling reason to convert your raw images to DNG is paranoia. If you're afraid that the multi-national corporate giant that manufactured your camera might one day go out of business, leaving you with no software to read your library of extant raw files, then switching to this new open standard is probably a reasonable thing to do. Even if Adobe ever goes under, the fact that the standard is freely published means someone will probably continue to provide software that's compatible with it.
Adobe is currently recommending that you save all of your original raw files, even if you convert to DNG. Because there is still undocumented private metadata in your original files, you'll want to have them around for maximum compatibility.
In testing the Digital Negative Converter with raw files from a Canon EOS 20D, it took my 1-GHz G4 PowerBook about 5 seconds per image to convert from Canon's CR2 format to the new DNG format. The resulting files were a little smaller -- down anywhere from 500 k to 1 GB. In other words, if you want to switch to DNG now, you'll have to devote some time to processing your images, and you're gonna need twice the storage that you're using now.
The real advantage to the end user will come from vendor support of the format. Because cracking a camera raw format is time consuming, few applications provide direct support for it. In theory, Adobe's published standard should make it much easier for any software developer to add raw support -- and not have to update it every time a camera is released -- meaning that your imaging workflow could one day be much more flexible.
The ideal future, of course, would be a camera that writes directly to DNG format. Obviously, this is what Adobe wants, not because they necessarily stand to make money from the adoption of their standard, but because they don't want to have to keep supporting new raw formats.
Whether vendors will go for this remains to be seen. At the time of this writing, none of the camera vendors we talked to were ready to make a statement about their DNG opinions.
What Now?
In theory, there are tremendous advantages to camera vendors: They don't have to develop, test, and maintain their own raw format; they get instant compatibility with Photoshop and any other app that supports DNG format; Adobe's support for "private" metadata means they don't have to give up on any of their own proprietary designs.
In the end, Adobe could choose to play hardball. If the new spec gains some momentum in the form of adoption by a majority of camera vendors, Adobe could simply stop providing support for proprietary raw formats, meaning that any camera that doesn't support DNG is locked out of the Photoshop raw workflow. For the serious photographer, this might be reason enough to choose a different camera.
Until more vendors -- software and hardware -- support it, DNG will remain just a promise of improved workflow. As a photographer, you probably don't need to concern yourself with the format yet, but it's worth keeping an eye on its development.
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