Sometime you may find defects in your photos.

Digital photos sometimes suffer from a defect called Noise, which makes your image appear as though someone sprinkled color sand over it. You can combat noise in two ways:

Add light, either by using your camera’s flash or switching on some other light source. Noise typically appears when the light is too dim.

If your camera offers a choice of a ISO settings, try lowering the ISO value too. This control increases your camera’s sensitivity to the light, allowing you to shoot in dim lighting. But on many cameras, a high ISO setting has the unwanted side affect of increasing noise. Of course, as you lower the ISO value, you need to add light to capture a good photo.