Abstract: The process behind compact cameras, capable of achieving high zoom ratios are described. In addition to the development of a suitable new type of zoom lens, the internal focusing is essential to the design. The study focuses upon current major lens types, especially a three- group zoom lens which are composed of positive, positive and negative refractive powers for respective lens groups. First, requirements on the development of zoom lenses are described. Then properties of lens types are discussed. Using similar specifications, applications of standard zoom lenses providing higher aperture are shown. The characteristics of these zoom lenses are then summarized.!19
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