Evolution of zoom lens optical design technology and manufacture

Zoom lenses have greatly improved to the extent that today many major performance characteristics are now equal to or come close to matching those of fixed focal length lenses. Some of these characteristics including size, weight, cost, producibility and general image performance are dependent on widely differing technologies. For example, optical design, coatings, refractive materials, surface types and the use of computers with suitable optical design software are just some of the technologies that when combined have driven the continuous development of zoom lenses and their optical designs.