The "ISO range" refers to the sensitivity of a camera's sensor to light, measured in ISO values. A lower ISO value, like 100, is ideal for bright conditions, while higher values, such as 1600 or 3200, are better for low-light situations. Adjusting the ISO can help achieve the desired exposure in photographs. Increasing the ISO can introduce noise, which appears as graininess in images. Photographers often balance ISO with other settings, like shutter speed and aperture, to maintain image quality while capturing the right amount of light. Understanding the ISO range is essential for effective photography.