Last week I bought the Panasonic GM1 and I love this little gem. When I turn the camera on I hear a noise. The manual says that the noise is because of the dust reduction function, but when I turn the camera on without a lens, I can see that the mechanical shutter is triggered (the noise sounds like that anyway). As far as I know, the dust reduction function works with ultrasonic vibrations, which are noiseless. The manual seems to be wrong here. Why is the mechanical shutter triggered each time I turn the camera on? This may not be a malfunction, but since that's the only one of my cameras which does that, I am quite curious. Does anybody know the reason?