A lens that allows you to choose one of many focal lengths is a...

• A. Prime lens
• B. Zoom lens
• C. Telephoto lens
• D. Wide angle lens

Answer: (B)

Adjustable focal length is what this item tests: a lens that lets you choose one of many focal lengths is a zoom lens. A zoom lens covers a range of focal lengths in one barrel, and you control the amount of magnification with the zoom ring to change the framing without moving closer or farther. This is opposed to a prime lens, which has a single fixed focal length, meaning you’d swap lenses or physically move to change the composition. While telephoto and wide-angle describe typical field of view at a given focal length, there are zoom versions of these as well; the defining feature here is the ability to pick among several focal lengths in one lens. For example, common zooms like 24-70mm or 70-200mm let you go from wide views to tighter portraits without changing lenses.