Image-forming optical system and apparatus using the same

An image-forming optical system comprising a decentered optical system constructed and arranged to image light from an object onto a surface of an image pickup device,

• wherein said image-forming optical system has at least one reflecting surface,
• said reflecting surface being a plane-symmetry three-dimensional surface which has no axis of rotational symmetry into or out of the surface and which has only one plane of symmetry,
• wherein said reflecting surface constitutes a reflecting surface of a prism member,
• said prism member being arranged such that optical paths in said prism member intersect each other crosswise.

An electronic camera apparatus comprising:

• an image-forming optical system having at least a decentered optical system to image light from an object on a surface of an image pickup device, said image-forming optical system including at least one reflecting surface having a reflecting action, said reflecting surface being a plane-symmetry three-dimensional surface which has no axis of rotational symmetry in nor out of the surface and which has only one plane of symmetry;
• an electronic image pickup device for receiving an image formed by said image-forming optical system;
• and
• a recording medium accommodated in said apparatus to record information concerning the image received by said electronic image pickup device.

An electronic image pickup apparatus comprising:

• an image-forming optical system having at least a decentered optical system to image light from an object on a surface of an image pickup device, said image-forming optical system including at least one reflecting surface having a reflecting action, said reflecting surface being a plane-symmetry three-dimensional surface which has no axis of rotational symmetry in nor out of the surface and which has only one plane of symmetry;
• an electronic image pickup device for receiving an image formed by said image forming optical system;
• and
• a board for integrally mounting said electronic image pickup device and other electric components as one unit.