Patent ID: 6560036
Filing Date: 2003-05-06
Classification: G02B

Abstract:
A real image type view finder comprising:an objective optical system which forms an intermediate image and has positive refractive power; an image erecting optical system which comprises at least a prism and erects said intermediate image; and an eyepiece optical system which leads said intermediate image to an observer's eye, wherein said objective optical system comprises, in order from the object side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having negative refractive power and a fourth lens unit having positive refractive power, changes a magnification by moving said second lens unit and said third lens unit, and satisfies the following condition (1): 0.97<Lr/S<1.2â€ƒâ€ƒ(1) wherein a reference symbol Lr represents an optical path length as measured from a location of the intermediate image to an object side surface of the eyepiece optical system and a reference symbol S designates a distance as measured from a most object side curved surface of the objective optical system to a most image side curved surface of the objective optical system.