OBSERVATION OPTICAL SYSTEM, VIEWFINDER EQUIPPED WITH OBSERVATION OPTICAL SYSTEM AND METHOD FOR MANUFACTURING OBSERVATION OPTICAL SYSTEM

摘要

An observation optical system for observing an object includes, in order from the object side: a first lens having positive refractive power; a second lens having negative refractive power and a concave surface facing the object side; and a third lens having positive refractive power and a convex surface facing an eyepoint side. An aspherical surface is included on at least one lens surface, and given conditional expressions are satisfied, thereby providing a compact observation optical system having excellent optical performance, a viewfinder equipped with the observation optical system, and a method for manufacturing the observation optical system.