Save Drive Space with DNG

“Hard Drives are cheap”. Well thats what we say. Sure, by the standards of a few years ago they are cheaper but when faced with finding an extra hundred bucks or so to get a new drive you may not agree with that statement. Especially when that hundred bucks only gets you a drive the same size as what you have, and what you really need is something twice its size. Tomorrow!
There are measures you can take to reduce your usage and reclaim drive space. You can:

Shoot less
Cull more images from your collection
Convert to DNG

Shooting less each time you go on a shoot is easy if you pretend you are using film but the built in motor drives of todays cameras make it too easy to burn through hundreds of frames without even thinking.
Culling images from your collection will save some space but there are certainly valid reasons not to bother. I’ll wager the amount of space you will save by deleting a few files here and there will not be sufficient reward for the time taken to do it.
So now we have our third option – DNG. That magical mystery of file formats.

The DNG file format is still a raw file, just in a smaller package. While Adobe created it, it is not proprietary, unlike CR2 or NEF. One of the best things about DNG files is they will save you as much as 20% of the space used by the manufacturers file. Thats like getting a 20% discount on any hard drive you purchase. I’ll take that.

So how do you create these DNG’s?

If your camera doesn’t shoot them natively (i.e Canon and Nikon users) you can convert them when you import them using Lightroom. Select the option to “Copy as DNG” at the top of the import dialog. Note that this will make a copy of your file and put it in a location you specify. You cannot “Add” files to the catalog and convert them to DNG but don’t worry we can convert them later too.

Just Do It

The drawback? It takes longer to import. Longer than what? Well longer than it would if you didn’t convert. (slap forehead here)
If you have 1GB of images to import then thats too few to be concerned with the additional time. So just do it.
If you have 16GB then chances are you’re going to do something else anyway while the import is taking place. Again, just do it.
The point being, don’t let the import time be a serious factor in your decision.

If you choose not to convert at the time of import (as I have done before) then you can convert after import from the Library Menu.

If you didn’t sort your images before electing to convert be sure to check the “Only Convert Raw Files” box as there is no reason to convert PSD TIF or JPG files to DNG. Its not that you can’t, I just see no reason to do so. But if you really want to read this

To delete or not to delete?

Once you have made the conversion you can delete the original Raw files or let Lightroom do it for you by checking “Delete Originals after successful conversion”.
For those of you who really want to keep the original files from the camera may I suggest you back those up as you import them to a specific drive or use another means to burn them to DVD disks.

On a recent job this was the result of a single days shoot. A 17% savings on drive space means faster backup times at the end of the day and that means you either get to bed earlier or get to the bar. Your choice.

In this instance the files were coming in at regular intervals allowing time for DNG conversion during the shoot rather than at the end of the day. You may choose to do all your conversions on Sunday afternoon while watching football. It doesnt realy matter when you do the conversion, the savings is the same. If you’re a low volume shooter, chances are, this is a hobby and you need to save every chance you can. If you’re a prolific shooter and this is a business then perhaps you’d like to reduce your CDB.
For more information on DNG as it relates to the photographer, I recommend this resource