bad news: your drive has failed
good news: it's still physically present and working
neutral news: you'll have to get a data recovery software to get your data back.
i can't speak for the product advertised in my link, i just know that it describes itself as a solution to your exact problem.http://www.z-a-recovery.com/art-raw-filesystem.htm
i usually pull the drive, plug it into my mac (no, not because it's a mac, because i already have data recovery software on it) and run a recovery on the drive. in this situation i've had a good success rate getting data off. some of the pictures have the grey bars, most dont and you might lose some metadata, but it's better than nothing.