When I’m on the road scouting locations or leading workshops, I use my MacBook Pro as my field computer. I store my images on a portable USB 3 hard drive and I use Lightroom on my laptop to manage, keyword, and process images.
The challenge with this approach is that Lightroom by its very nature is a single-user application. Unless you store your Lightroom catalog file on a portable drive, it means that you’re going to have to set up two catalogs: one on your main computer and one on your laptop. Keywords and adjustments are not stored in your images unless you use DNG files, so simply copying the images from the laptop to your desktop computer won’t preserve all your Lightroom adjustments.
The solution I use is to do the following while in the field:
I keep my Lightroom catalog on the laptop’s internal drive (a fast SSD for maximum performance). My images are stored on the external drive, using the same directory structure that I use on my main computer. In this case, the basic directory structure is Pictures/Year/. This matches the top-level directory on my main image storage drive on my desktop computer.
It’s important to keep the top-level directory naming the same if you want to have your images imported to your main hard drive in the same organizational structure. When I get home from my travels, I use the Lightroom Library module to select the folder(s) of images I wish to transfer, right-click, and choose “Export as Catalog.” This creates a separate catalog file of just the folder(s) you selected. Since my images are already on my external drive, I don’t check the “export negative files” option. If you saved your images your laptop’ internal drive, you’ll need to export them, too.
Next, connect your portable drive to your desktop computer and launch your normal Lightroom catalog. Use the “Import from Another Catalog” command to import your images. In the dialog box, you can specify where to copy the negative files (images).
Depending on the number of images being copied, the import process may take awhile. Once it’s complete, you’ll see all your images with their keywords, labels, and adjustments intact in your main catalog.