I'm just backing up a shoot I did for a friend's son's 18th birthday party. I took about 280 shots, have processed about 85 and that's it, all done. I make that less than 400 images. On exporting them to a back-up drive, these have apparently become over 3,000 items amounting to about 66 gigabytes of data. That would give me about 800 raw files from my D800. What on earth is going on?