WIDE-ANGLE LENS SYSTEM

• Main Author: SHIODA RYO
• Format: Patent
• Language: English; Japanese
• Published: 19.03.2020
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

To provide a wide-angle lens system which is configured to suppress both image height variation during wobbling and aberration variation due to change in in-focus position through appropriate placement of a focusing group.SOLUTION: A wide-angle lens system disclosed herein comprises a first lens group G1 having negative refractive power and a succeeding lens group GR having positive refractive power as a whole, where the succeeding lens group GR comprises an aperture stop S, a front-side lens group GP disposed on the object side of the aperture stop, and a focusing lens group GF disposed on the object side of the front-side lens group GP and configured to move for focusing, the front-side lens group GP and the focusing lens group GF having positive refractive power. When zooming from the wide-angle end to the telephoto end, at least an air gap distance between the first lens group G1 and the succeeding lens group GR narrows. The wide-angle lens system satisfies specific conditional expressions.SELECTED DRAWING: Figure 1 【課題】フォーカス群を適切に配置することで、ウオブリング時の像高変動と合焦位置の変化による収差の変動の両方が抑制された広角レンズ系を提供する【解決手段】物体側より順に、負の屈折力を有する第１レンズ群Ｇ１と全体として正の屈折力を有する後続レンズ群ＧＲより構成され、 前記後続レンズ群ＧＲは、開口絞りＳと、その物体側に絞り前側レンズ群ＧＰと、さらにその物体側に合焦に際して移動する合焦レンズ群ＧＦを有し、前記絞り前側レンズ群ＧＰと前記合焦レンズ群ＧＦは正の屈折力を有し、広角端から望遠端への変倍に際して、少なくとも前記第１レンズ群Ｇ１と前記後続レンズ群ＧＲの空気間隔が減少し、特定の条件式を満足することを特徴とする広角レンズ系。【選択図】図１