How are sharpness and spatial resolution related?

• A. If something is blurred (unsharp), you can't distinguish objects close together.
• B. They are independent and unrelated.
• C. Increasing resolution always degrades sharpness.
• D. Sharpness only affects high-contrast edges.

Answer: (A)

Sharpness and spatial resolution are tightly connected: when an image is blurred, the boundaries between nearby features smear together, so two objects that are close can no longer be distinguished.

Sharpness describes how clearly edges and fine details are rendered, while spatial resolution is about the smallest separation at which two features can still be told apart. Blur reduces the high-frequency information that carries fine detail, so closely spaced objects blend into one another and the ability to resolve them is lost.

That’s why the statement reflecting this relationship is the best: loss of sharpness directly limits how well you can separate close objects. The other ideas don’t fit because they either imply independence between sharpness and resolution, claim that higher resolution degrades sharpness, or limit sharpness to high-contrast edges, none of which accurately describe how blur affects our ability to resolve detail.