Zoom lenses are available in many focal length ranges. Zoom lenses for 35mm cameras have been around for many years. Early zooms were big, heavy, expensive and left much to be desired in terms of optical performance. The selection of zooms and the focal length ranges they covered were equally limited. Improvements in design, lens coatings, alloys and plastics plus evolution are now providing us with zooms that are reasonably priced, cover a wide zoom range and virtually match the image quality of fixed focal length lenses.
Zoom lenses are available in just about the same range of focal lengths as non-zoom lenses.
The 35-70mm has a comparatively narrow zoom range, but it is quite compact and is commonly used as a substitute for a 50mm normal lens. The other mid-range zooms are larger and heavier, but can be used in place of normal lenses, too. Telephoto zoom lenses are widely used for portraits, travel, scenics, sports and candid photos. They are useful for sports and wildlife photography. Long zooms can be used for many of the same purposes as shorter telephoto zooms, but they are larger, heavier and often slower in speed.