Using a wide aperture (low f-number) results in which depth of field?

• A. Shallower Depth of Field
• B. Greater Depth of Field
• C. No Change in Depth of Field
• D. Infinite Depth of Field

Answer: (A)

A wider aperture opens the lens more, letting in more light and producing a shallower depth of field. Depth of field is the range of distances that appear acceptably sharp in the image. With a large opening, the circle of confusion for points not exactly on the focus plane grows, so foreground and background blur increases and only a small band around the focus stays sharp. That’s why a portrait taken with a wide aperture often has a blurry background while the subject remains crisp. If you wanted more of the scene sharp from near to far, you’d use a smaller aperture, which increases depth of field. The other options describe outcomes you’d see with smaller apertures or extreme conditions, not with a wide one.