| 摘要 |
PURPOSE:To obtain an ultra telephoto objective lens which has an about 1:7 aperture ratio by allowing the ultra telephoto objective lens consisting of the 1st lens group with positive power and the 2nd lens group with negative power from an object side to meet specific requirements. CONSTITUTION:The objective lens system consists of the 1st positive-power lens group of one positive lens and one negative lens and the 2nd meniscus lens group which has a convex surface on the object side and small negative power from the object side, and respective parameters satisfy specific conditional inequalities (1)-(6). Consequently, the ultra telephoto objective lens which has a large diameter and a flat image plane, consists of a small number of elements, and has small spherical aberration and chromatic aberration is obtained. |
