Patent ID: 7085048

Claim:
A real image type variable magnification finder comprising, an object optical system having positive refracting power which forms an objective image as a middle image, a view frame arranged near a position of the middle image, and an eyepiece optical system having positive refracting power which forms a pupil for observing the middle image, wherein a plurality of image erecting optical surfaces for making an erect image by bending an optical path are formed on the way of optical paths of the object optical system and the eyepiece optical system, wherein the object optical system comprises, in order from an object side, a negative lens component which is a single lens and a positive lens component which is a single lens, both of the negative lens component and the positive lens component being moved in a magnification change while changing a distance therebeteween, wherein the eyepiece optical system comprises a prism having an entrance surface that is a convex surface directed toward the object side and arranged on a pupil side of the middle image, and a positive lens component which is a single lens, wherein the view frame is arranged on the object side of the entrance surface of the prism, wherein the image erecting optical surfaces are formed to be divided before and after the position of the middle image, wherein, in an entire system of the real image type variable magnification finder, a total number of lens components and prisms each having refracting power is four, the lens components and prisms each having refracting power being composed of plastic, and wherein the following condition is satisfied: 0.8 <|fn/fp|< 1.8 where fn represents a focal length of the negative lens component of the object optical system, and fp represents a focal length of the positive lens component of the object optical system.