Reflecting type of zoom lens

An optical device, comprising:

• an optical unit having an aspherical reflection surface of rotational asymmetry in which there exists no more than one plane of symmetry,
• wherein a position of said optical unit is varied to change a focal length or to perform focusing.

An optical device comprising:

• an optical unit having an optical medium which has a first surface having an optical power and a second surface having an optical power, said optical unit forming an intermediate image in said optical medium between said first and second surfaces,
• wherein each of said first and second surfaces is an aspherical surface of rotational asymmetry,
• wherein a position of said optical unit is varied to change a focal length or to perform focusing.

A phototaking optical system comprising:

• a first optical surface that is an aspherical reflection surface of rotational asymmetry in which there exists no more than one plane of symmetry,
• a second optical surface that is an aspherical reflection surface of rotational asymmetry in which there exists no more than one plane of symmetry,
• wherein an image of an object is formed at an image pickup medium by way of both said first optical surface and said second optical surface.

A phototaking optical system comprising:

• an optical surface that is an aspherical reflection surface of rotational asymmetry in which there exists no more than one plane of symmetry;
• and
• means for changing an optical path length between said optical surface and an image pickup medium.

An optical device, comprising:

• an optical unit having an aspherical surface of rotational asymmetry in which there exists no more than one plane of symmetry,
• wherein a position of said optical unit is varied in an optical axis direction to change a focal length or to perform focusing.

An optical device comprising:

• an optical unit having an optical medium which has a first surface having an optical power and a second surface having an optical power, said optical unit forming an intermediate image in said optical medium between said first and second surfaces,
• wherein each of said first and second surfaces is an aspherical surface of rotational asymmetry,
• wherein a position of said optical unit is varied in an optical axis direction of said device to change a focal length or to perform focusing.

A phototaking optical system for use with an image pickup medium, said system comprising:

• an optical surface that is an aspherical surface of rotational asymmetry in which there exists no more than one plane of symmetry;
• and
• means for changing a distance between said optical surface and the image pickup medium.

An apparatus, comprising:

• an optical element composed of a solid transparent body, having two refraction surfaces and a plurality of aspherical reflection surfaces, whereby a light beam entering said transparent body from one of said two refraction surfaces is reflected by said plurality of aspherical reflection surfaces in order and then is projected from the other refraction surface, wherein each of said plurality of aspherical reflection surfaces has such a shape that there is no more than one symmetry plane which can define one pair of symmetrical surfaces.

An apparatus comprising:

• an optical element having an aspherical reflection surface which decenters a light beam entering therethrough, and
• an aperture diaphragm located at a light incidence side of said optical element,
• wherein the aspherical reflection surface is tilted relative to a reference axis and has such a shape that no more than one plane of symmetry exists which can define a pair of symmetrical surfaces.

An apparatus, comprising:

• an optical element composed of a solid transparent body, having two refraction surfaces and a plurality of reflection surfaces comprising a plurality of aspherical reflection surfaces, whereby a light beam entering said transparent body from one of said two refraction surfaces is reflected by said plurality of aspherical reflection surfaces in order and then is projected from the other refraction surface,
• wherein each of said plurality of aspherical reflection surfaces has such a shape that there is only one symmetry plane which can define one pair of symmetrical surfaces.

An apparatus comprising:

• an optical element having an aspherical reflection surface which decenters a light beam falling incident on the surface, and
• an aperture diaphragm located at a light beam incidence side of said optical element,
• wherein the aspherical reflection surface has only one plane of symmetry which can define a pair of symmetrical surfaces.