The degree of magnification in a camera lens. If it is adjustable, then the lens can Zoom. Non-zoom lenses are called prime lenses. For 35mm film, a wide-angle lens will have a focal length of about 15-35mm, a normal lens about 40-60mm, and a telephoto or long-focus lens about 100-1000mm (or very rarely, even more). Focal length is not the same as the distance of the camera's focus. If a camera is properly adjusted, then an object in focus at maximum zoom should be in focus at all zoom levels. Extremes of focal length can produce optical distortion.