| 摘要 |
PURPOSE:To reduce the size of a zoom lens having an about 2 variable magnification ratio and an about 76 deg. angle of view and to simplify its constitution by composing a front lens group of a negative, a positive, a negative, and a positive lens and a rear lens group of a positive, a positive, a negative, and a positive single lens, and by making the lens system meet specific requirements. CONSTITUTION:A lens system consists of a front negative lens groups and a rear positive lens group; the front lens group consists of four single lenses which are a negative meniscus lens L1 whose concave surface faces an image side, a positive lens L2, a negative lens L3 whose very concave surface faces the image side, and a positive meniscus lens L4 whose convex surface faces an object side successively from the object side, and the rear lens group consists of four single lenses which are a convexo-convex positive lens L5, a positive meniscus lens L6 whose very convex surface faces the object side, a concavo-concave negative lens L7, and a positive lens L8 successively from the object side. In addition, respective lenses meet requirements shown by conditional equalities (1)-(4). |
