Night vision mode refers to the ability of a device to continue to capture images in low light or dark environments. It uses infrared light to illuminate the scene and allows the camera to capture images in low light conditions. This allows you to see what is happening in the dark, even if you cannot see it with your own eyes. The purpose of night vision mode is to continue to capture usable images in low light environments. If night vision mode is not turned off, the screen you see in low light environments will be black.