A shallow depth of field is achieved by using a wide aperture. Which option represents wide aperture?

• A. Wide aperture
• B. Narrow aperture
• C. Fast shutter speed
• D. Low ISO

Answer: (A)

A wide aperture means a large lens opening, which lets in more light and creates a shallow depth of field. That shallow depth of field makes the subject come out sharp while the background blurs, which matches the idea of a shallow focus. So the option describing a wide aperture is the best choice. The other ideas relate to different aspects: a narrow aperture increases depth of field and keeps more of the scene in focus; fast shutter speed affects motion blur, not depth of field; and low ISO changes exposure and noise, not how much of the scene is in focus. In portrait work, you might use a wide aperture such as f/2.8 or f/1.8 to achieve that blurred background.