The shutter of a camera synchronized with the blades of a helicopter to take off. In the port of Hong Kong, a person filmed take-off of a helicopter and had time to synchronize the shutter of the camera with the main frequency of rotation of the rotor to give this strange effect. We have the impression that the levite magically helicopter. You should know that the blades of a helicopter rotate at approximately 30 revolutions per seconds. It took so that the person shooting at 30 frames per second to give the illusion that the blades are fixed.