anyone familiar with this? it was also titled with the following: G ED SW DX not entirely sure with the letters mean but could someone shed some light on this for me? they watn $245.00 from the store used. Apparently my kit 18-55 is about to break seeing as when i zoom it something inside is grinding, so im gonna need a new one soon i should also say im just looking for a decent all around lens. also in addition to this, can another recommendation be made for for a wide angle? these will all be going on my D40 thanks!