Which statement best describes the effect of using a small aperture on depth of field?

• A. It decreases depth of field
• B. It has no effect on depth of field
• C. It increases brightness
• D. It increases depth of field

Answer: (D)

Using a small aperture (a high f-number) increases depth of field, meaning more of the scene—from near to far—appears in sharp focus. This happens because a smaller opening reduces the range of distances that fall outside the sharp focus, so the circle of confusion for objects away from the focus point stays smaller and acceptable focus extends across a larger depth. In practice, this is why landscapes are often shot with a small aperture. The trade-off is less light reaches the sensor, which may require a longer shutter speed or higher ISO; and at very small apertures diffraction can soften image detail. The statement that describes increased depth of field is therefore the correct one, while the others would imply no change, a decrease, or an increase in brightness, which aren’t accurate for how aperture affects depth of field.