Posted by James Maynard – May 01, 2013
The latest of the great arguments among photographers is the choice of whether to begin the digital editing process in raw or .DNG format. Of course, we are here at Mosaic try to bring you all the information we can about the subject at hand (which we love photography)
Although much discussion is made of .RAW files, there is no such thing as a single “.RAW” file format. Raw is a bucket term for several different types of formats like .cr2, .nef, r3d., and dozens of others. A file that is a perfectly good “raw file” for products from one manufacturer may be gibberish on other camera’s systems. This is entirely unlike .PNG or .JPG files, which are readable across various platform.
Most professional photographers and serious amateurs shoot in the raw format, giving their files all the information needed for the best possible editing. But, there is an option within Lightroom to convert your raw formated pictures into digital negatives, or .DNG files. In order to decide if that is the right move, let’s learn a little bit about each file format.
When you shoot in raw format, you are recording the unadulterated, complete file with all the original data intact, which makes it such a great choice for editing. Since you did not “throw away” any information when you were taking the photograph, you have a great deal of flexibility when it comes to editing your photographs afterward.
Not all raw files are created the same – cameras from different manufacturers can have incompatible ways of organizing that information, so don’t be surprised if software that worked with the raw files of one camera will not work with a different device. This use of proprietary versions of raw format may be the undoing of the standard over time.
This is why raw converting tools are not created equally… although software packages like Google Picasa can “support raw files” how they interpret the camera sensor data varies greatly and can lead to very different final product images.
The .DNG format solves this problem by taking the raw image and converting it to a digital negative which is recognized by a wide variety of software applications. Just as film negatives were/are compatible with any enlarger, the .DNG format is compatible with many software applications, including Adobe Lightroom.
You can think of it as the .PDF of the digital photo world. The compatibility rate for .DNG files is actually higher than it is for raw format, so a wide number of applications will be able to import photos into your library in .DNG format. This is partly because of the fact that when Adobe developed this standard in 2004, they released the converter and the exploitation rights for free to developers.
Since you will still be shooting in raw format, and only converting to .DNG on import, the files on your memory card will remain unchanged. The .DNG format, while retaining all the original image data, does dispose of some of the metadata that accompanies raw files, but does not affect image quality, such as camera settings and focus points. That means that a .DNG file will be about 15% smaller than an identical raw file. However, the image quality of the photographs themselves are identical. This helps improve the one big drawback of shooting in raw – the larger file size of these formats compared to .JPG or .TIFF.Part of this data is contained in another file which accompanies raw files, called a .XMP file. This folder contains information about editing performed on the photograph. Occasionally, they can become dislodged from their partner files, leading to trouble. This processing information is stored within .DNG files, eliminating the need for a separate .XMP.Another advantage of importing as .DNG files is that they contain a checksum safety feature that easily and quickly identifies a corrupted file. This is called embedded file verification. However, the actual importing times may be not be as sped up as you might think by the reduction in file size – because the original raw files need to be converted to .DNG, there will be some lag added by that process.
Whether you decide to begin your photo processing in raw or .DNG format, you will be shooting them in raw, so there is no harm in trying an import as .DNG and seeing what happens. No matter which photo editor you are using, tell us below about your experiences using .DNG.
I have just made the switch to DNG format from my RAW files. Adobe offers a free Raw to DNG converter on their website. It’s simple to use and the resulting files are smaller than the original RAW files. I like the fact that being Digital Negatives you only have one file not two using the camera specific RAW file created by your camera. File viewers and editors like Adobe Bridge can get corrupted or confused and stop working. DNG files are universally accepted, kind of the “one size fits all” mentality. Below is the first DNG file I shot and edited in Photoshop CS6.1 for Mac today.