I doubt that there's any pressure displacement as the camera itself is not watertight. As such air would be able to enter the camera from within the housing and take up the space that the lens occupies when retracted, there would be no pressure change.Mark_Schilling said:This is just me thinking out loud, but I wonder if there's an issue with pressures when the zoom lens is extended and retracted. Perhaps the displacement of air from the housing into the camera (when the lens is extended, and the opposite when retracted) causes stress on the seals of the camera lens?