About a year ago I attached the Olympus ZD 25mm f2.8 to my GF3 and it worked fine although AF was a bit slow. Now I don't have GF3 anymore. But when I tried to use the ZD 25mm on my GX1, it can't autofocus properly. The barrel moves back and forth and then stops without getting a clear focus. This is my first time to attach this lens on GX1, never done it before. Any idea how to solve the problem?