Adobe Photoshop CS5 for Photographers - Martin Evening [114]
The DNG solution
Fortunately there are third-party companies who have devized ways of processing some of these raw formats, which means that you are not always limited to using the software that came with the camera. Adobe is the most obvious example here of a company who are able to offer a superior alternative. At the time of writing, Camera Raw can recognize raw formats from over 275 different cameras.
DNG adoption
Over the last few years DNG has been adopted by many of the mainstream software programs such as iView (now Microsoft Expression), Capture One, Portfolio and Photo Mechanic. At the time of writing, Hasselblad, Leica, Samsung and Ricoh cameras all support a DNG raw capture format option. You might also like to visit the www.openraw.org site where you can join the Open Raw discussion group and read the results of their 2006 raw survey.
The DNG (digital negative) file format specification came about partly as a way to make Adobe's life easier for the future development of Camera Raw, and make Adobe Photoshop compatible with as many cameras as possible. DNG is a well thought out file format that is designed to accommodate the many different requirements of the proprietary raw data files in use today. DNG is also flexible enough to adapt to future technologies and has recently been updated to work with cameras that store proprietary lens correction data in the raw file. Because DNG is an open standard, the specification is freely available for anyone to develop and to incorporate it into their software or camera system. It is therefore hoped that the camera manufacturers will continue to adopt the DNG file format and that DNG will at some point be offered at least as an alternative file format choice on the camera.
Using DNG brings several advantages. Since the DNG format is a documented open standard, there is less risk of your raw image files becoming obsolete. There is the potential for on-going support for DNG despite whatever computer program, computer operating system or platform changes may take place in the future. This is less likely to be the case with proprietary raw files. Can you imagine in, say, 25 years' time there will be guaranteed support for the CR2 or NEF files shot with today's cameras?
Should you keep the original raws?
It all depends on whether you feel comfortable discarding the originals and keeping just the DNGs. Some proprietary software such as Canon DPP is able to recognize and process dust spots from the sensor using a proprietary method that relies on reading private XMP metadata information. Since DPP is a program that does not support DNG, if you delete the original CR2 files you won't be able to process the DNG versions in DPP. The only solution here is to either not convert to DNG or choose to embed the original raw file data when you convert to DNG. This means you retain the option to extract the CR2 raw originals any time you need to process them through the DPP software. The downside is that you end up with bloated DNG files that are at least double in size.
DNG compatibility
When raw files are converted to DNG the conversion process aims to take all the proprietary MakerNote information that is sitting alongside the raw image data in the raw original and place it into the DNG. Therefore, any external DNG-compatible software should have no problem reading all the raw data that is rewritten as a DNG. However, there are known instances where manufacturers have placed some of the MakerNote data in odd places, such as alongside the embedded JPEG preview, which at one point was discarded during the conversion process