Today’s Question: You’ve said a variety of things about the Adobe DNG [digital negative] file format, some good and some bad. But what I really want to know is, all things considered, should I convert my raw captures to DNG?
Tim’s Quick Answer: In a word, no. Taking all of the various factors into account, my personal preference (and general recommendation) would be to retain the original raw captures from your camera, and to not convert those original captures to the Adobe DNG format.
More Detail: Let me say right from the start that there are absolutely some great benefits to the use of the Adobe DNG file format compared to proprietary raw capture formats. I’m not suggesting that converting raw captures to DNG is somehow “bad”. I simply feel that on balance I’d rather retain the original raw capture format rather than converting those files to DNG and deleting the original captures. And I also don’t feel it makes a lot of sense to both convert to DNG and still retain your original raw captures.
One of the key reasons I prefer to retain the original raw captures is that they represent the original capture with no modification whatsoever. While the Adobe DNG format retains the pixel data from your original capture, there are some “private” metadata from the camera that may be lost. That information would generally relate to unique features of a specific camera model, which would require software from the camera manufacturer to fully leverage.
I also prefer to keep metadata updates separate from the original capture data. In the context of a raw capture that means, for example, having metadata updates written to an XMP “sidecar” so that the original capture file remains undisturbed. This can also help to streamline a backup workflow.
One of the primary motivations for using the Adobe DNG format is to avoid a proprietary file format that is not openly documented the way the DNG format is documented. In addition, DNG files are generally around 20% smaller than the original raw capture, with no loss of image quality or detail. So there are indeed advantages to the Adobe DNG file format, to the extent that if your camera supports capture directly to DNG, you may want to make use of that option.
But in the context of a workflow that might involve discarding the original raw capture file after converting to the Adobe DNG format, my preference is to simply retain the original capture files.