The exposure triangle is made up from the shutter speed, aperture and ISO of a camera, which all work together to give us a perfect exposure. The aperture is the size of the hole which light is passed through in the lens, the smaller the number the larger the opening. The shutter speed also allows us to august the amount of light coming into the camera, the longer the shutter speed the more light is allowed in. Finally ISO control the sensitivity of our camera to light, the lower the number the less sensitive therefore the less light. however the when more light is let in the image can become grainy, we call this noise. there is a meter in our camera that can automatically adjust one of these if you change another however this can change depending on the quality of light available. we usually set two of the three manually and the mere in the camera will change the other for us. we can chose which we would like to adjust depending on the type of photo we are taking.