What happens if the ISO is set too high when photographing in low light?

When ISO is set too high in low light conditions, the resulting image can appear grainy or noisy. ISO measures the sensitivity of your camera's sensor to light; a higher ISO allows for better performance in dim lighting but at the cost of image quality. The noise manifests as random specks of brightness or color, which can detract from the overall clarity and smoothness of the image.

In low light photography, while using a high ISO helps capture more detail, the compromise is that image noise becomes more pronounced, leading to a less desirable aesthetic. Photographers often seek a balance between ISO, aperture, and shutter speed when working in low light to mitigate this effect, preferring to keep the ISO as low as possible to maintain the integrity of the image.