I took a number of pictures of my kids playing in a park with the 45-200mm on GH1. I got some good results, but quite a few were disappointingly soft, especially at the long end of the 200mm. I shot mostly wide, at the shutter speed of at least 1/200 to freeze motion, with the OIS turned on. I'm trying to figure out the possible reason and wanted to hear experience of others. Possible reason for the softness: Optics The lens is not that sharp at 200mm period? The lens is not sharp wide open at 200mm? Should have stopped down a bit? Camera shake the optical IS doesn't work that well at 200mm? Autofocus 45-200mm is not good at AF at the 200mm end GH1 is not good at AF at that range To me, the autofocus is a good suspect, because I got some back-focused shots at closer range even with a stationary subject for some reason. Other factors may have contributed too. Can people with similar past experience share their view? The remedy for next time will depend on this analysis.