This part is a must if you want to run the Cam without Geäuse. This is the Cam still more compact and lighter and to get everything off (battery etc). Who runs the Cam without this protection or protective housing is very fast risk that the lens gets scratches and thus the cam becomes unusable. However, since it's just plastic, a star (actually 2) deduction. Gopro competitor shows it exemplary, here replaceable real glass filters or slices offered. Not only therefore remains Gopro for me also the first choice. Through the Sony protection has not really - at least directly - observable sharpness loss, as long as the protection is clean. But plastic is harder to clean, always with microfiber cloth.