Originally posted by dh4412 are there more ' natural' ( for lack of better term ) methods of achieving the same thing for the shadows and highlights, if this feature stays off?
Sometimes there is. Highlight protection can save your blown out sky. You can also save that blown out sky with a graduated filter (colloquial: ND grad filters). Highlight protection can also save your blown out windows or other highlights. A filter can't do the same.
Shadow correction can "lift" the deep shadows. Sometimes you can also do that with flash and other times you can't.
These two settings have subtle effects but believe me, they work. Once you learn to see what they do, you'll appreciate them.
Adam mentioned they slow down processing. Well maybe they do, but it's not much. You can still shoot action at full burst speed with highlight and shadow protection.
Another downside is more noise. But that's a nonissue at low iso on the K-5. I wouldn't use the d-range features above say ISO 800 or so.
Regards,
--Anders.