Over this semester, I was assigned to take pictures based on the aperture. The aperture on the camera controls the focus of the foreground and background of the image you are taking. In order to get a sharp picture all around, with everything in focus, your camera should have a small aperture opening (see first image in gallery). If as the photographer you want to have a blurred background and only have the object of choice in focus, you should have a large aperture opening (see second picture in gallery).