ISO 1600 is a standard measurement of a camera's sensitivity to light. The ISO scale typically ranges from 100 to 6400 and higher, with lower numbers indicating less sensitivity and higher numbers indicating more sensitivity. When set to ISO 1600, a camera can capture images in lower light conditions without using a flash, making it ideal for indoor photography or evening events. Using ISO 1600 can result in brighter images, but it may also introduce more noise or graininess, which can affect image quality. Photographers often balance ISO settings with aperture and shutter speed to achieve the desired exposure while minimizing noise.