I do not own Lightroom (I beta'd Lightroom before it was a v1.0 product). I use Aperture (but that's only available for Mac).
The advantage of these are that they are specifically optimized for RAW workflow. The original image out of the camera is treated like a negative out of a film camera... it is never changed.
As you apply changes, the changes are only displayed on screen. The changes themselves are not written back to the the RAW. Aperture (and likely Lightroom but I don't own Lightroom) does create a "thumbnail" version and a "preview" (JPEG) version which is MUCH smaller than the original RAW and these are ONLY so that you can go flying through your albums looking for the image you want. As soon as you stop on that image to view it full screen, the program opens the original RAW and then reads the list of adjustments that have been performed and literally applies them on-the-fly to the image on screen.
The adjustments are not applied in image-form (they only exist as a "meta data" instructions... data which represents the adjustments to all the various things... white balance, exposure, shadows & highlights, color, saturation, curves/levels, etc. etc. The computer can represent these changes as a set of instructions rather than altering the actual pixels in the image itself.)
The ADVANTAGE of this... is that photographers change their mind. Say you made 5 adjustments... and a few weeks later you're looking at that same image and you decide that you don't like one of the adjustments you made. If the adjustments were actually applied to the original pixels of the image, then you'd be stuck with them (this is a "destructive" change because the original data is now gone... it's been replaced by new data). But since Aperture and Lightroom keep track of the changes as a metadata list of instructions... you can always just remove one of those instructions (or change it).
They do actually apply the adjustments when exporting a version of an image (e.g. when you decide to produce a print... or export a JPEG to share on the web, etc.) But the original data is always safe -- nothing is ever destroyed.
These tools are easy to use (much easier than learning Photoshop -- there are no "layers"... you don't have to make "selections" to affect changes, etc.) Also if you take a whole shoot in the same light, many global changes should probably be applied to every image taken in that same light (e.g. they probably all need the same "white balance" adjustment). This is another area where the RAW workflow processing of Lightroom and Aperture shine because it's a snap to adjust an image to your likeing... and then tell the software to apply all (or many) of those adjustments to a whole range of images that you shot that day.
Tim Campbell
5D III, 5D IV, 60Da
