Convex Mirror: Virtual Focus and Wide Field of View

Theory

A convex mirror spreads parallel rays out as if they came from a virtual focus behind the mirror, at $f=-R/2$. Images are always virtual, upright and smaller, which gives a wide field of view — used in car side mirrors and shop security mirrors.

What to observe

• Reflected rays diverge; extended backwards (dashed), they meet at F behind the mirror.

Try this

• Change R: a smaller radius spreads the rays more.
• Switch to concave and compare.

Also available in: Espelho convexo: foco virtual e campo de visão amplo (Português) · Espejo convexo: foco virtual y campo de visión amplio (Español)