What characterizes a zoom lens?

A zoom lens is characterized by its ability to provide multiple focal lengths, which allows the photographer to zoom in and out without needing to change the lens on the camera. This versatility enables users to frame their shots from varying distances while maintaining the same lens. For instance, a zoom lens can cover a range of focal lengths such as 18-55mm, allowing for wide-angle to moderate telephoto shots.

It is important to differentiate this from a fixed focal length lens, often called a prime lens, which offers only one focal length and thus does not permit zooming capabilities. Additionally, while some zoom lenses can be used for macro photography, this is not exclusive to them, as macro photography can also be accomplished with specialty macro lenses. A zoom lens, by its nature, is designed to adjust its focal length, meaning it is capable of focusing on subjects at various distances as needed, contrary to the characteristics of a lens that cannot adjust focus.