Real image mode variable magnification finder
OwnerShigeru Katoinventor
Life of this patent
Estimating the term…
Abstract
A real image mode variable magnification finder has an objective optical system with positive refracting power, an image erecting optical system, and an ocular optical system with positive refracting power. The objective optical system has a first lens unit with negative refracting power, a second lens unit with negative refracting power, a third lens unit with positive refracting power, and a fourth lens unit with negative refracting power. When the magnification of the finder is changed, at least one lens unit, namely the third lens unit is moved. In this way, the total length of the objective optical system can be reduced, and thus a compact finder is obtained.
Claims10
A real image mode variable magnification finder comprising:
- an objective optical system with positive refracting power;
- an image erecting optical system;
- and
- an ocular optical system with positive refracting power,
- said objective optical system having a first lens unit with negative refracting power, a second lens unit with negative refracting power, a third lens unit with positive refracting power, and a fourth lens unit with negative refracting power, and
- at least one lens unit, namely said third lens unit being moved when a magnification of said finder is changed.
A real image mode variable magnification finder comprising:
- an objective optical system with positive refracting power;
- an image erecting optical system;
- and
- an ocular optical system with positive refracting power,
- said image erecting optical system including a prism and a mirror, and
- said ocular optical system having at least two lenses composed of a fixed lens and a moving lens.
Dependencies are inferred from the claim text.