Today’s Question: I was recently told by a Lightroom guru that when importing images shot in RAW into Lightroom, they actually come in as JPEG images. If that is true, what then is the advantage of shooting in RAW?
Tim’s Quick Answer: Your raw captures are not converted to JPEG images upon import into Lightroom, so you can indeed retain the original raw captures and the benefits those captures provide. The previews of your captures viewed within Lightroom (other than in the Develop module) are JPEG previews, however.
More Detail: It is possible you may have misunderstood what that Lightroom guru was saying (or that they weren’t in fact a guru).
Lightroom does indeed enable you to import (and therefore retain) supported proprietary raw capture formats. The confusion about converting to JPEG probably relates to the previews that Lightroom generates for your images. You can choose, for example, to generate “Standard” previews for all of your images upon import. These are essentially JPEG images that are approximately the size of your monitor display (depending on your Preferences setting and monitor configuration).
The previews Lightroom generates enable you to view your images more quickly in the Library module, and also to view a preview of the image even when the source files are not available, such as when an external hard drive containing your photos is disconnected from the computer. In the Develop module a full preview based on the source image is generated and updated in real time as you apply adjustments.
So, JPEG previews are most certainly created for your images when you import them into Lightroom or view them within the Library module, but those JPEG previews do not replace your original raw captures. The actual source files you imported would still be available. The only other exception to this would be if you converted your proprietary raw captures to the Adobe DNG format during import, but in that case you would still have the DNG version of your image, which is similar in concept (and provides the same quality) as your original raw capture.