Shooting in Hong Kong under dusty day, it is hardly avoid dust fall on the CMOS Sensor. For the best practice to minimize the dust fall inside the camera, we should place the camera upright when changing the lens, just press the lens release button, rotate and remove the lens. When attach the lens, please do not point the camera to sky, which dust will easily fall on the mirror or shutter blade. Also, do not point the camera to ground. When facing downward, the camera is certainly protected. However, the real lens is facing up, and leaving a large surface area to collect dust. After the lens attached on camera, with few shoots taken, the dust may fall on the CMOS Sensor. Therefore, simply place the camera in upright position when changing the lens.