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Wide-angle zoom lens system

  • US 5,359,457 A
  • Filed: 09/18/1992
  • Issued: 10/25/1994
  • Est. Priority Date: 10/03/1991
  • Status: Expired due to Term
First Claim
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1. A wide-angle zoom lens system, comprising from the object side to the image side:

  • a first positive lens unit being stationary on an optical axis during a zooming operation;

    a second negative lens unit shifting along the optical axis during the zooming operation;

    a third positive lens unit being stationary on the optical axis during the zooming operation; and

    a fourth positive lens unit shifting along the optical axis during the zooming operation;

    wherein the zoom lens system fulfills the following conditions;

    
    
    space="preserve" listing-type="equation">0.155<

    Φ

    1Z·

    Y'"'"'.sup.3 /fs.sup.2 <

    0.355
    
    
    space="preserve" listing-type="equation">0.040<



    1/|Φ

    2|)·

    (Y'"'"'/fs).sup.3 <

    0.065wherein;

    Φ

    1 represents a refractive power of the first lens unit;

    Φ

    2 represents a refractive power of the second lens unit;

    Y'"'"' represents a maximum image height;

    fs represents the shortest focal length of said zoom lens system; and

    Z represents a zoom ratio.

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