OPTICAL SYSTEM AND IMAGE CAPTURING DEVICE

• Main Author: NAKADA TAKEHARU
• Format: Patent
• Language: English; Japanese
• Published: 30.09.2021
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

To provide a compact optical system which is suitable for macro lenses and capable of suppressing aberration variations.SOLUTION: An optical system is provided, comprising an aperture stop SP2, a front focusing group LPF with positive refractive power located on the object side of the aperture stop, a rear focusing group LPR with positive refractive power located on the image side of the aperture stop, and a rear group LN with negative refractive power located on the image side of the rear focusing group. When shifting focus from an object at infinity to a nearby object, the front focusing group and the rear focusing group move towards the object side. The optical system satisfies a condition expressed as: 0.1≤|fLN/f|≤0.6, where fLN represents a focal length of the rear group and f represents a focal length of the optical system.SELECTED DRAWING: Figure 1 【課題】マクロレンズに好適な小型で収差変動の抑制が可能な光学系を提供する。【解決手段】光学系は、開口絞りＳＰ２と、開口絞りよりも物体側に配置され、正の屈折力を有する前側フォーカス群ＬＰＦと、開口絞りよりも像側に配置され、正の屈折力を有する後側フォーカス群ＬＰＲと、後側フォーカス群より像側に配置され、負の屈折力を有する後群ＬＮとを有する。無限遠物体から近距離物体へのフォーカシングに際して、前側フォーカス群と後側フォーカス群は物体側に移動する。後群の焦点距離をｆＬＮ、光学系の焦点距離をｆとするとき、０．１≦｜ｆＬＮ／ｆ｜≦０．６なる条件を満足する。【選択図】図１