LENS SYSTEM, IMAGE CAPTURING DEVICE, AND MOBILE BODY

• Main Authors: NAKATSUJI TATSUYA, ADACHI TOMOKO, MATSUNAGA SHIGEHIKO
• Format: Patent
• Language: English; Japanese
• Published: 07.10.2021
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

To provide a large-aperture wide-angle lens system that offers high resolution.SOLUTION: A lens system 100 comprises a first lens group G1, an aperture stop S, a positive second lens group G2, a negative third lens group G3, and a positive fourth lens group G4 in order from the object side. The first lens group has two negative meniscus lenses L1, L2 having convex surfaces on the object side disposed on the most object side. The third lens group consists of two or less lenses L12, L13. The fourth lens group comprises at least one positive lens L14 and at least one negative lens L15, and a negative lens is disposed on the most image side. The third lens group moves toward the image side when shifting focus from infinity to an object nearby. The lens system satisfies conditions expressed as: 3.5<|f1/f|, 2.1<f4/f<5, vd1-2>50, where f1 represents a focal length of the first lens group, f4 represents a focal length of the fourth lens group, f represents a focal length of the entire system, and vd1-2 represents an average Abbe number of the two negative meniscus lenses of the first lens group for the d-ray.SELECTED DRAWING: Figure 1 【課題】高い解像力を有する大口径で広角なレンズ系を提供する。【解決手段】レンズ系１００は、物体側より順に、第１レンズ群Ｇ１、絞りＳ、正の第２レンズ群Ｇ２、負の第３レンズ群Ｇ３、正の第４レンズ群Ｇ４を備える。第１レンズ群の最も物体側には、物体側に凸面を向けた２枚の負のメニスカスレンズＬ１，Ｌ２が配置され、第３レンズ群は２枚以下のレンズＬ１２、Ｌ１３で構成され、第４レンズ群は、少なくとも１枚の正レンズＬ１４と負レンズＬ１５を含み、最も像側に負レンズが配置される。無限遠から近距離被写体へのフォーカシングの際に、第３レンズ群が像側へ移動する。ｆ１を第１レンズ群の焦点距離、ｆ４を第４レンズ群の焦点距離、ｆを全系の焦点距離、ｖｄ１−２を第１レンズ群の２枚の負のメニスカスレンズのｄ線における平均アッベ数として、３．５＜｜ｆ１／ｆ｜、２．１＜ｆ４／ｆ＜５、ｖｄ１−２＞５０、を満足する。【選択図】図１