×

Finder optical system and image pickup apparatus using the same

  • US 20040027475A1
  • Filed: 08/01/2003
  • Published: 02/12/2004
  • Est. Priority Date: 09/07/1999
  • Status: Abandoned Application
First Claim
Patent Images

1. A finder optical system comprising, in order from an object side thereof:

  • an objective optical system having a positive refracting power;

    an image-inverting optical system for erecting an intermediate image formed by said objective optical system; and

    an ocular optical system having a positive refracting power;

    wherein said objective optical system has;

    at least two movable units moving when zooming is performed; and

    a prism placed on an object side of the intermediate image formed by said objective optical system, said prism including at least one reflecting surface having a rotationally asymmetric surface configuration;

    said image-inverting optical system having at least one reflecting surface formed from a roof surface;

    said finder optical system satisfying the following condition;

    1.0<

    d
    /(fW·

    tan θ

    w·

    Z
    )<

    2.5 



    (1) where d is a distance from an entrance surface of said objective optical system to a first reflecting surface of said image-inverting optical system;

    fW is a focal length of said objective optical system at a wide-angle end;

    θ

    w is a maximum field angle of said objective optical system at the wide-angle end; and

    Z is a zoom ratio.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×