Patent ID: 7509046

Claim:
A finder optical system, comprising: a relay optical system operable to reform a subject image at a secondary image-formation position wherein the subject image is a primary image formed at a primary image-formation position through an objective optical system, and an eyepiece optical system operable to view an image re-formed through the relay optical system, wherein: the finder optical system comprises at least four reflecting surfaces including an F 3 reflecting surface, an F 2 reflecting surface, an F 1 reflecting surface and an R 1 reflecting surface located between the primary image-formation position and the secondary image-formation position side and in an optical path order from a primary image-formation position side to a secondary image-formation position side, at least one positive lens located between the F 1 reflecting surface and the R 1 reflecting surface, and an R 2 reflecting surface located between the R 1 reflecting surface and the secondary image-formation position, and at least one positive lens located between the R 1 reflecting surface and the R 2 reflecting surface. the finder optical system has an optical axis reflected at each of the reflecting surfaces (FIG. 3), and the light ray exits the F 2 and R 1 reflecting surfaces in an opposing direction of said light ray as it exits the eyepiece optical system.