Changing the aperture during a video shoot is essential for managing depth of field and exposure, especially when transitioning between scenes with varying lighting conditions. For instance, moving from a dark room to bright outdoor settings requires adjusting the aperture to maintain proper exposure and achieve the desired depth of field. This adjustment is crucial to ensure that the footage remains visually consistent and avoids overexposure or underexposure. Additionally, altering the aperture can enhance creative effects, such as isolating subjects with a shallow depth of field or ensuring more of the scene is in focus in brighter conditions.