Finder optical system
AssigneeMinolta Camera Kabushiki Kaisha
InventorsHiromu Mukai, Yasumasa Sugihara
Life of this patent
Estimating the term…
Abstract
A finder optical system provided separately from a photo-taking lens comprises, from the object side: an object lens from forming a primary image which is an inverted image of an object and for erecting the primary image to form an erecting image; and an eyepiece for enlarging said erecting image. The object lens comprises a gradient index lens.
Claims15
A finder optical system provided separately from a photo-taking lens, comprising from the object side to the image side;
- an object lens for forming a primary image which is an inverted image of an object, said object lens comprising a gradient index lens and a constant index lens;
- means for erecting the primary image to form an erecting image, and
- an eyepiece for enlarging said erecting image, wherein the constant index lens has a negative refractive power and is arranged at the object side of the gradient index lens.
A finder optical system provided separately from a photo-taking lens, comprising from the object side to the image side;
- an object lens for forming a primary image which is an inverted image of an object, said object lens comprising a gradient index lens;
- means for erecting the primary image to form an erecting image, and
- an eyepiece for enlarging said erecting image, wherein the finder optical system has a plurality of gradient index lenses having a different focal length from each other, and only one of the gradient index lenses is arranged on an optical axis of the finder optical system as the object lens.
A finder optical system provided separately from a photo-taking lens comprising from the object side to the image side;
- an object lens for forming a primary image which is an inverted image of an object, said object lens comprising a gradient index lens;
- means for erecting the primary image to form an erecting image;
- and
- an eyepiece for enlarging said erecting image, wherein the object lens comprises two gradient index lenses, one or which is always arranged on the optical axis of the finder optical system, and the other of which is retractably arranged on the optical axis.
A finder optical system provided separately from a photo-taking lens, comprising from the object side to the image side;
- a gradient index lens for forming an erecting image of an object, said gradient index lens functioning as an object lens and an image erecting optical system, and
- an eyepiece for enlarging said erecting image.
In a camera having a photo-taking lens system, the improvement of a separate finder optical system of a compact configuration, comprising from the object to the image side:
- an object lens unit for forming a primary image including a gradient index lens;
- means for erecting the primary image to from an erect image, and
- an eyepiece for enlarging the erect primary image for an observer.
Dependencies are inferred from the claim text.