Viewing apparatus having a photographic function

• US 20030086164A1
• Filed: 09/27/2002
• Published: 05/08/2003
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Pentax Corporation (Hoya Corporation)
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Abe, Tetsuya
• Granted Patent: US 6,788,454 B2
• Time in Patent Office: Days
• US Class Current: 359/407
• CPC Class Codes: G02B 23/12 with means for image conversion or intensification

Abstract

A viewing apparatus with a photographing function, includes a viewing optical system by which an image of an object, formed by a positive objective optical system, is viewed though a positive eyepiece optical system, and a photographing optical system which is provided independently from the viewing optical system. The photographing optical system covers substantially the same field of view as that of the viewing optical system. The viewing apparatus satisfies the following condition:

0.1<ft/fo<0.7   (1)

wherein

ft designates the focal length of the photographing optical system, and

fo designates the focal length of the objective optical system of the viewing optical system.

Claims

1. A viewing apparatus with a photographing function comprising a viewing optical system and a photographing optical system;

wherein said viewing optical system comprises a positive objective optical system and an eyepiece optical system, in this order from an object;

wherein an image of an object, formed by said positive objective optical system, is viewed though said eyepiece optical system;

wherein said photographing optical system is provided independently from said viewing optical system, and said photographing optical system covers substantially the same field of view as that of said viewing optical system;

wherein said viewing apparatus satisfies the following condition;

0.1<

ft/fo<

0.7

wherein

ft designates the focal length of said photographing optical system of said viewing apparatus, and

fo designates the focal length of said objective optical system of said viewing optical system.

2. A viewing apparatus according to claim 1, wherein said eyepiece optical system has a positive power, and satisfies the following condition:

5<

fo/fe

wherein

fe designates the focal length of said positive eyepiece optical system of said viewing optical system.

3. A viewing apparatus according to claim 1, wherein said viewing optical system comprises a viewing-optical-system focusing mechanism which substantially maintains an image forming position by moving at least a portion of said viewing optical system in the optical axis direction in accordance with a change in distance to the object;

and

wherein said photographing optical system comprises a photographing-optical-system focusing mechanism which adjusts an image-forming position of an object to a predetermined position by moving at least a portion of the photographing optical system in the optical axis direction in accordance with a change in distance to the object; and

an associated-focusing mechanism which operates said viewing-optical-system focusing mechanism and said photographing-optical-system focusing mechanism in an associated manner.

4. A viewing apparatus according to claim 1, wherein said viewing optical system comprises a telescope comprising a positive objective optical system, and a positive eyepiece optical systems through which an image formed by said objective optical system is viewed.

5. A viewing apparatus according to claim 1, wherein said viewing optical system comprises a binocular comprising a pair of positive objective optical systems and a pair of positive eyepiece optical systems through which an image formed by the objective optical systems is viewed.

6. A viewing apparatus according to claim 5, wherein the optical axis of said photographing optical system is positioned between the optical axes of said pair of viewing optical systems of said binocular.

7. A viewing apparatus according to claim 1, wherein said photographing optical system forms an object image on an image pick-up device, and records said object image.

8. A viewing apparatus according to claim 1, wherein said photographing optical system comprises a positive first lens group comprising a positive lens element and a negative lens element, and a positive second lens group comprising a positive lens element and a negative lens element, and said photographing optical system satisfies the following condition:

0.15<

D_I-II/f<

0.6

wherein

D_I-II designates the distance between said positive first lens group and said positive second lens group, and

f designates the focal length of said entire photographing optical system.

9. A viewing apparatus according to claim 8, satisfying the following conditions:

1<

AC_I/AC_II 20<

υ

_lp−

υ

_ln

wherein

AC_I designates the total sum of the absolute values of the reciprocal of the product of the focal length and the Abbe number (|1/(fi*υ

i)|) of each lens elements in said positive first lens group; and

AC_II designates the total sum of the absolute values of the reciprocal of the product of the focal lengths and the Abbe number (|1/(fi*υ

i)|) of each lens elements in said positive second lens group.

υ

_Ip designates the Abbe number of said positive lens element of said positive first lens group, and

υ

_In designates the Abbe number of said negative lens element of said positive first lens group.

10. A viewing apparatus according to claim 9, wherein said positive lens element and said negative lens element of said positive first lens group are cemented to each other.