Certified Professional Photographer (CPP) Practice Exam

To achieve a shallower depth of field in photography, the aperture setting needs to be adjusted. When you choose a wider aperture—indicated by a smaller f-stop number, such as f/2.8 or f/1.8—you allow more light to enter the camera. This wider opening creates a more pronounced effect where the subject is in sharp focus while the background and foreground become more blurred. This effect is particularly desirable for portrait photography, where emphasizing the subject against a softer backdrop can enhance the visual appeal. In contrast, adjusting the ISO influences the camera's sensitivity to light, which can help in low-light conditions but does not directly affect depth of field. Likewise, shutter speed is related to the duration of time the camera's sensor is exposed to light and is more pertinent for freezing motion or controlling exposure rather than altering depth of field. Lastly, white balance is specifically about color temperature and correcting color casts present in the photograph, and therefore does not impact depth of field at all. Thus, adjusting the aperture is the critical factor for achieving a shallower depth of field, making it the correct choice in this context.