| 摘要 |
PROBLEM TO BE SOLVED: To obtain a finder optical system having wide observation magnification, having long eye relief, facilitating the adjustment of finder field and obtaining high optical performance, and optical equipment using the same. SOLUTION: In this finder optical system where an image formed by an objective lens is observed through an eyepiece, the eyepiece is constituted of a negative lens L1, a positive lens L2 whose both lens surfaces are convex, and a negative lens L3 whose concave surface faces to an eye point side in the order from an object side. When it is assumed that (f) is the focal distance of the eyepiece at one diopter, f2 is the focal distance of the lens L2, Rif is the radius of curvature of the object-side lens surface of an (i)-th lens counted from the object side, and Rir is the radius of curvature of the eye-point-side lens surface of the (i)-th lens counted from the object side, conditions 0.25<|f2/f|<0.75 and 2.0<(R3f+R3r)/(R3f-R3r) are satisfied.
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