There are two advantages to using a ballast weight with your camera. If you are planning to use natural light or the small flash of the camera in shallow water you will not experience the positive buoyancy of the bare camera. It also helps when you are hand holding your strobe for special light effects you're your camera suddenly becomes buoyant. Without accessories, the camera is positive buoyant; the camera floats. For negative buoyancy without accessories, attach the ballast weight.