The Photography Tip of the Week #051
051 Photography Tip of the Week (audio)
No to Native RAW, Yes to DNG
For those of you who use a camera that saves in JPG format, this tip won’t do you much good. But I do think you might glean a bit of useful information out of it. So read on. I like my steaks like I do my photo file format, RAW. But I’m not allowed to eat much red meat anymore so I’ll just have to stick to RAW images. Those of you who make RAW photos know the advantages of RAW. You have an extreme amount of exposure and color control over the image after it’s on your machine. Since memory is relatively cheap, photographing in RAW is a no-brainer. But what RAW format should you save your file in. Adobe created an alternate RAW format that is open (well almost) and has a lot of advantages over the native RAW format from your camera. There are a number of photographers out there that will shoot down DNG saying that there is no reason to switch since Adobe may not be in business for as long as you need to store your files, or that you may lose image information in DNG. All I can say is that in several hundred thousand files, I haven’t seen anything negative about the DNG format and have nothing but praise. Below are the reasons I convert my files to DNG.
File size – The amount of space that DNGs take up are less by about 15% on average. I know I said earlier that memory is cheap, but when you create thousands of photos a year, that space savings adds up very quickly. But this is one of those things where you can say “prove it” and I can come up with the numbers. So for my first photo I made an image of a plain white door. Awe inspiring I know. The native RAW file is 9.8MB and the DNG is 9.5MB. Not a huge amount of savings only creeping in at a little above 3%. But this is an image with little to no detail in it.
So now here’s an image with a little more going on. It’s a photo of a rug. The native RAW file is 12.2MB and the DNG is 11.1MB giving us a little more than 9% in savings. But one could argue that there’s not a lot going on in the image and the native RAW storage mechanism could be well suited for this type of image. So I took the size of all of the images of the day. This came in at 534.8MB and the directory after conversion to DNG is 454.0MB giving us a little more than 15% savings. This a reason I like the DNG format over the native RAW format. For 1TB (1000GB) of photo files, I save 150GB of space. One could say that 150GB of space is cheap enough to just pay for the difference. But you have to take into consideration increased load time and if you perform a backup to a cloud server, an added 15% size could make it difficult for your photo backup to keep up.
Meta data goes with the file – One of the powerful features with RAW format files is the ability to make changes to the the image without affecting the original data. So you can change, and change settings without destroying the original data like you would with a JPG file. The way the changes are recorded is in a set commands so each time you open the file it re-runs the commands to give you your developed image. This string of commands is stored in a “side car” file normally with the extension of .XMP. These files aren’t very big, but if you ever move the image file you have to move the side car file in order to keep your development settings. With DNG the settings/commands are stored in the file and go with it if you ever move it to another directory.
These are the two big reasons I use DNG over the native RAW file format. I hope you will take a look at DNG as your file format for all of your RAW images. So you to can save some space and keep your development settings with your image.
