There are distinct characteristics that are related to changes in aperture and shutter speed. Shutter speed controls the length of time the light has to strike the sensor; consequently, it also controls the blurriness (or lack of blurriness) of the image. The less time light has to hit the sensor, the less time your subjects have to move around and become blurry. This lets you control things like freezing the motion of a fastmoving subject or intentionally blurring subjects to give the feel of energy and motion (Figure 2.11).
The aperture controls the amount of light that comes through the lens, but also determines what areas of the image will be in focus. This is referred to as depth of field, and it is an extremely valuable creative tool. The smaller the opening (the larger the number, such as f/22), the greater the sharpness of objects from near to far. A large opening (or small number, like f/2.8) means more blurring of objects that are not at the same distance as the subject you are focusing on (Figure 2.12).
As we further explore the features of the camera, we will learn not only how to use the elements of exposure to capture properly exposed photographs, but also how we can make adjustments to emphasize our subject. It is the manipulation of these elements—motion and focus—that will take your images to the next level.