What three ways can you control depth of field?

• A. Shutter speed, ISO, and white balance
• B. Focal length of lens, aperture, and camera to subject distance
• C. Sensor size, megapixels, and frame rate
• D. Lighting ratio, color temperature, and hue

Answer: (B)

Depth of field is shaped by three practical levers you can adjust directly in the field: focal length of the lens, the aperture setting, and how far you are from the subject. A wider aperture (smaller f-number) makes the background blurrier and reduces depth of field, which is why portraits often use a shallow DOF to separate the subject. Using a longer focal length tightens the field of view and naturally narrows the depth of field, increasing background blur for the same framing. Getting closer to the subject also reduces depth of field, while stepping back increases it, again for the same framing.

The other elements listed affect exposure or color rather than depth of field. Shutter speed, ISO, and white balance control exposure and color tone, not how much of the scene is in acceptable focus. Sensor size can subtly influence depth of field because it changes the circle of confusion and how we perceive sharpness, but the direct, actionable controls you use to manage DOF are the lens focal length, the lens aperture, and the distance to the subject.