What is the effect of changing ISO settings in photography?

Changing ISO settings in photography primarily affects the exposure of an image. ISO measures the sensitivity of the camera's sensor to light. A higher ISO setting allows the sensor to collect more light, which is particularly useful in low-light conditions, resulting in a brighter image. Conversely, a lower ISO setting reduces sensitivity, leading to darker images in similar lighting conditions.

By manipulating the ISO, photographers can achieve the desired exposure without altering other settings like aperture or shutter speed. However, it's important to note that increasing the ISO can introduce more noise (graininess) in the image, so finding the right balance is key for optimal image quality. This direct relationship between ISO and exposure is fundamental in achieving well-exposed photographs under varying lighting conditions.