I thought this was fairly well documented. My understanding of this was the 105/TRV33 etc have a magnetic zoom which can be "overpowered" by opening shock, I've seen it plenty of times on footage from these cameras. I bought a trv33 and then sold it un-used for this reason! If you turn the camera off and tilt it back and forward and look into the lens you will see the the internal lens sliding back and forth. The pc9 and the new pc330 doesn't do this hence no blur, I just wondered what kind of zoom the Panasonic had.
I only BASE jump now so the opening shock maybe a little more brutal than skydiving openings...
Neil