5. RAW OR DNG—IT’S YOUR CHOICE

AS YOU ARE importing pictures into Lightroom, you will notice that you have two options at the very top of the Import window: Copy as DNG and Copy (Figure 5.1).

The DNG file format is an archival format that was designed by Adobe to combat the large number of different RAW camera formats that are out there. Every manufacturer has a different proprietary RAW format, so it requires a bunch of different types of software to read each file type. Adobe’s idea was to create one standard format so that all of these files can be read. Camera companies are a little slow to adopt the DNG format, but there is a lot of benefits to it when you use it.

The first benefit that you will immediately see is that the DNG file size is usually smaller than its RAW counterpart. This has a lot to do with the fact that the compression method Adobe uses to convert the RAW file to the DNG format is a little bit better than what you would see with the proprietary format.

Another benefit to the DNG format is that proprietary RAW files usually have an XMP file attached, which means there are two files to worry about. The RAW file is the raw data and the XMP sidecar file is a text file that goes along with the RAW file to monitor the changes you’ve made to it. By converting to a DNG format, all of that information is stored in a single file.

DNG files also have the ability to use “fast-load data,” which is supposed to increase the speed at which you can preview the files, and they support “image tiling,” which speeds up the reading of the file. Let me give you an oversimplified version of how this works.

Your computer has a processor and inside that processor are cores—four core processors, five core processors, eight core processors. These cores are almost like worker bees that are attacking a specific problem; each core is a bee.

Figure 5.1 You can create a DNG file right from the Import window.

Now, imagine if a RAW file is presented to these cores. A proprietary RAW file will be read by only one core of your computer. So the worker bee attacks the core, while the other worker bees sit and watch. It’s a very inefficient way for your computer to attack the information.

If you convert to a DNG format, multiple cores will attack the same file and accomplish the task in a smaller amount of time. So, with the DNG format, you have a smaller file that can be read faster and it’s one file instead of two. You can’t go wrong with that.

However, the decision is up to you and you don’t have to convert to the DNG format during the import process. You can copy your images into Lightroom automatically without converting to a DNG format. Once the images are in the Lightroom Catalog, you can go to the Library module and select Library > Convert Photos to DNG from the menu bar (Figure 5.2).

Here you can specify what you want to convert, how big you want the preview to be, and whether or not you want to use the fast load data (Figure 5.3).

My advice to you would be to convert a couple of files to the DNG format and see if you’re okay with the process. If you like what you see and you love the performance and smaller file size of the DNG files (Figure 5.4), then chances are the DNG format is in your future.

Figure 5.2 In the Library module, you can covert your RAW files to DNG after they’ve been imported.

Figure 5.3 Converting RAW files to DNG in the Lightroom Catalog.

Figure 5.4 A side-by-side comparison showing just how much space you save by using the DNG format. The DNG file is 4.5MB (18%) smaller than the original RAW file.