A benefit of the electronic viewfinder on the Olympus OM-D E-M5 is the ability to change the aspect ratio and compose your shots with the correct result shown in the viewfinder. This is easier than using the viewfinder of a DSLR and trying to guess what, say, a square composition will look like after cropping.
If you do this in RAW mode, the camera still records the full 4:3 image that the sensor saw. This is apparent in playback in the camera, where you see your crop superimposed on the full 4:3 image. But it's not apparent when you load the file into Lightroom (as of version 4.3). In Crop & Straighten mode in Lightroom, you'll just see the cropped image and won't be able to recover the full 4:3 image. The data is there in your RAW file, but you can't see it in Lightroom.
Adobe provides a Lightroom plug-in to help, called the
Adobe DNG Recover Edge plug-in. As the name suggests, it requires converting your RAW files to DNG, but everything can be done within Lightroom. After installing the plug-in, to recover the full 4:3 image:
- Select the image(s) in the Library
- Select Library > Convert Photo to DNG...
- Review the settings for DNG conversion (particularly whether you want to retain the original RAW file), and complete the conversion
- Select the converted image(s)
- Select Library > Plug-in Extras > DNG Recover Edges > Apply
Using the plug-in in step 5 creates a copy of each intermediate DNG file created in step 3 and imports it, so now in your Library you have each cropped original and a new non-cropped copy (with "_full" appended to the file name), with the aspect ratio reset to 4:3.
At what point in your process should you use the plug-in? Personally I prefer to keep the original RAW files in my Library, with the aspect ratio I shot them at, so I can see the composition I intended. I only use the steps above if I need to recover more of the image. That works because the steps above retain any adjustments and metadata changes you've already made using the RAW file (similar to a Virtual Copy, although it's a new file).
The downside of this approach is that the new file created by the plug-in has its History reset to start with a new Import at the time you used the plug-in. That's awkward if you need the History but would prefer to delete the intermediate DNG file. On the other hand, using the plug-in on all your RAW images right after importing them means their aspect ratios will be reset to 4:3, so you'd have to recompose every image with the aspect ratio you shot it at.
A compromise would be to start converting RAW to DNG at import. Then steps 1-3 above don't apply. I'm not at that point yet -- the potential long-term benefits of DNG are a whole other topic, covered
here,
here, and
here.