The three main camera modes/exposure are IOS, aperture, and shutter speed. It is really important for you to be able to know how to use these camera modes. Because it determines how dark or light your picture is, or how blurry it is. Aperture means how much light you let into the camera lens which means it determines how dark your picture can be and how light it can be. Your shutter speed controls how fast the shutter closes. The slower the shutter closes the blurrier the picture is. And your IOS controls the given amount of light that goes to your camera sensor.