Watermark will appear when the camera takes pictures at night.
The normal phenomenon is that when you turn on the flash, the dust in the air will reflect when you use the astigmatism lamp in a bad light environment, so it can only be repaired by PS. It is recommended that you don't turn on the flash in the future. Generally, the effective distance of the flash of the camera is only 3 meters, which will cause poor results if it is too far away.