Final answer:
The aperture is the part of the camera that controls the amount of light entering through the lens, measured in f-stops, affecting both exposure and depth of field.
Step-by-step explanation:
The aperture is the size of the opening in the camera that light passes through. When referring to aperture in the context of photography, it is measured in f-stops. A larger aperture (a lower f-number) means more light is let into the camera, whereas a smaller aperture (a higher f-number) lets in less light. This plays a crucial role in both the exposure and depth of field of your photographs. Adjusting the aperture affects not only the brightness of the photo but also the depth of field. A larger aperture results in a narrower depth of field, thus isolating the subject from the background by making it sharp against a blurry backdrop.