When you take a picture with your camera, the flash unit emits a very brief burst of intense light. This blue light is part of the visible spectrum and is perfectly safe for your eyes. However, if you look at the blue light directly, it can be quite dazzling.
The blue light is used to illuminate your subject so that the camera’s sensor can record a accurate image. When the flash goes off, it illuminates everything in front of the lens equally. This can cause problems if your subject is close to the camera because they will be overexposed (too bright). To avoid this problem, most cameras have a built-in flash unit that tilts up slightly when it fires. This “bounces” the light off of the ceiling or another nearby surface before it reaches your subject, which softens the light and prevents overexposure.