Image Formation by a Convex Mirror

Unlike a concave mirror, a convex mirror doesn't change its story depending on where the object is. Wherever you place the object — right up close or far at infinity — the image is always virtual, erect, and diminished (smaller than the object), and it always forms behind the mirror, between the pole and the focus.

This predictability is exactly why convex mirrors are used as rear-view and side mirrors on vehicles. Because the mirror curves outward, it captures a much wider field of view than a flat mirror would — letting a driver see more of the road behind them in one glance. The trade-off is that objects appear smaller (and therefore farther away) than they really are — which is why these mirrors often carry the warning 'objects are closer than they appear'.