The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 11, 2009
Filed:
Mar. 02, 2007
Akio Arakawa, Saitama, JP;
Akio Arakawa, Saitama, JP;
Tamron Co., Ltd., Saitama, JP;
Abstract
The present invention is directed to a high variable power zoom lens that ensures a flange-back or a backfocal distance required for typical 35-mm film cameras while keeping an angle of view sufficient to cover the wide-angle for an APS-size imaging plane dimensioned smaller than 35 mm. The high variable power zoom lens has the first lens group Lof positive refractivity closest to the subject, the second lens group Lof negative refractivity second closest to the subject, the third lens group Lof positive refractivity, and the fourth lens group Lof positive refractivity farthest from the subject, and the zoom lens satisfies the requirements 0.6≦|f|/fW≦0.73 where fis the focal length of the second lens group and fW is the focal length of the entire optics moved to the wide-angle end, and also satisfies the requirements 2.2≦f/fW≦3.7 where fis the focal length of the third lens group.