I'm looking to delete 50% of my 40,000 + library of photos and I know that a large portion of those photos are low quality for quick consumption and can be discarded. I've been sorting manually through photos and I find that my tendency is to delete photos that aren't perfectly sharp (with some exceptions). I see that it's possible to search photos by sharpness but I don't know what to put in the value field. I looked at the EXIF data of my photos and I don't see a Sharpness field. Most of my photos were shot on a D200 and D300. What values do I use to search my library by sharpness?