EYEPIECE OPTICAL SYSTEM AND OPTICAL EQUIPMENT MOUNTED THEREWITH

摘要

PROBLEM TO BE SOLVED: To provide an eyepiece optical system having excellent optical performance by securing high finder magnification and long eye relief while achieving the upsizing of an optical system, and optical equipment in which the eyepiece optical system is mounted. SOLUTION: In the eyepiece optical system 1, a subject image formed on a focusing screen 14 (predetermined image-formation surface) by an objective 11 is turned into an erect image by a pentagonal prism (erect optical system) 16, and the erect image is observed through an eyepiece 18. The eyepiece 18 comprises a first lens group L1 having negative refractive power and a second lens group L2 having positive refractive power along an optical axis in order from an object side, and an optical prism (optical path dividing means) 17 is arranged between the pentagonal prism 16 and the first lens group L1 of the eyepiece 18. When the thickness of the optical prism 17 in the optical axis direction is denoted as PL, and the entire length from the emitting surface of the pentagonal prism 16 to the third lens group (lens nearest to the eye point EP side) of the eyepiece 18 is denoted as TL, the eyepiece optical system 1 satisfies a following expression; 0.10