| 摘要 |
PURPOSE:To obtain a clear high-performance zoom lens with a wide viewing angle by constituting a lens system of six groups of six lenses and satisfying a specified condition. CONSTITUTION:The lens system is constituted of six groups of six lenses such as a 1st group of a concave lens 10, a 2nd group of a convex lens 12, a 3rd group of a concave meniscus lens 14, a diaphragm 15, a 4th group of a concave meniscus lens 16, a 5th group of a convex lens 18 and a 6th group of a concave lens 20. Supposing that the focal distance of the 1st group is f1, the focal distance of the 2nd group is f2 and the compound focal distance of all the system in the case of unmagnification is f0, expressions I and II are allowed to be satisfied. Thus, various aberrations are excellently compensated in the magnification area of a wide range from 1.414 magnifications to 0.70 magnifications in spite of a small number of lenses. |
