I bought one when they first came out. That one got sold when I changed to Canon aps-c. Once I saw the error of my ways I bought back into mft including a second one. I got my third when Olympus were giving them away as a freebie with an OM-D kit. Spent a while using Fuji gear and now back with mft, hence no 4! Simple, really" fourth copy of this lens (!) " -- why #4?