convex mirror
A convex mirror is a spherical mirror whose reflecting surface curves outward, like the outside of a ball.
- Unlike a concave mirror, a convex mirror always produces an image that's upright and smaller than the object, whatever the distance — the image only shrinks slightly further as the object moves away.
- Because it curves outward, a convex mirror captures a much wider field of view than a flat mirror of the same size — exactly why vehicle side-view mirrors, road safety mirrors at blind corners, and store surveillance mirrors are all convex.
- That wider view comes with a well-known catch: since the image is diminished, objects can look farther away than they really are — the reason side mirrors carry the warning that "objects in mirror are closer than they appear."
- A convex mirror spreads out (diverges) any parallel beams of light that hit it, the exact opposite of what a concave mirror does to the same beams.
Bulging outward like the back of a spoon, a convex mirror always shrinks what it shows — and quietly makes it look farther away than it really is.