Real image type zoom finder

A real image type zoom finder comprising, in order from an object side thereof, a positive objective optical system and a positive eyepiece optical system and further including an image-inverting means for erecting a real image formed by the objective optical system, wherein:

• said objective optical system comprises a plurality of moving groups, and
• said objective optical system further comprises, in order from an object side thereof, a reflecting surface having negative power and a reflecting surface having positive power on an eyepiece optical system side with respect to an intermediate image-formation plane, with at least one of said reflecting surfaces being defined by a rotationally asymmetric surface.

A real image type zoom finder comprising, in order from an object side thereof, a positive objective optical system and a positive eyepiece optical system and further including an image-inverting means for erecting a real image formed by the objective optical system, wherein:

• said objective optical system comprises a plurality of moving groups, and
• said eyepiece optical system comprises, in ray propagation order from an object side thereof, a first transmitting surface, a first reflecting surface, a second reflecting surface and a second transmitting surface, wherein said first transmitting surface is provided separately from said first and second reflecting surfaces, said second transmitting surface is defined by a surface common to said first reflecting surface, said first reflecting surface has negative power, said second reflecting surface has positive power, and at least said second reflecting surface is defined by a rotationally asymmetric surface.

A real image type zoom finder comprising, in order from an object side thereof, a positive objective optical system and a positive eyepiece optical system and further including an image-inverting means for erecting a real image formed by the objective optical system, wherein:

• said real image type zoom finder includes a plurality of moving groups and at least three reflecting surfaces on an objective optical system side with respect to an intermediate image-formation plane, and
• said real image type zoom finder includes positive reflecting surfaces on an eyepiece optical system with respect to the intermediate image-formation plane, at least one of which reflecting surfaces is defined by a rotationally asymmetric surface.

A real image type zoom finder comprising, in order from an object side thereof, a positive objective optical system and a positive eyepiece optical system and further including an image-inverting means for erecting a real image formed by the objective optical system, wherein:

• said objective optical system comprises at least one fixed group and a plurality of moving groups, and
• said eyepiece optical system comprises positive reflecting surfaces, at least one of which is defined by a rotationally asymmetric surface.

A real image type zoom finder comprising, in order from an object side thereof, a positive objective optical system and a positive eyepiece optical system and further including an image-inverting means for erecting a real image formed by the objective optical system, wherein:

• said objective optical system comprises a plurality of moving groups and at least five aspheric surfaces, and
• said eyepiece optical system comprises positive reflecting surfaces, at least one of which is defined by a rotationally asymmetric surface.

A real image type zoom finder comprising, in order from an object side thereof, a positive objective optical system and a negative eyepiece optical system and further including an image-inverting means comprising a plurality of reflecting surfaces for erecting a real image formed by the objective optical system, wherein:

• said objective optical system comprises a plurality of moving lens groups and one prism acting as an image-inverting means,
• said one prism comprises, in ray propagation order from an object side thereof, an entrance surface, a first reflecting surface, a second reflecting surface, a third reflecting surface and an exit surface wherein any of said first reflecting surface, second reflecting surface and third reflecting surface is defined by a roof surface provided that when an axial chief ray is projected onto a plane defined by three points on an axial chief ray at said entrance surface, said first reflecting surface and said second reflecting surface, said axial chief ray takes an optical path which, on the basis of the direction of propagation of a light ray, turns in the same direction at the first and second reflecting surfaces and turns in a direction different from said direction at the third reflecting surface.