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:
Jun. 12, 2012
Filed:
May. 26, 2011
Dayong LI, Saitama, JP;
Dayong Li, Saitama, JP;
Tamron Co., Ltd., Saitama, JP;
Abstract
The present invention is a variable power zoom lens that is suitable to APS-format single-lens reflex cameras. The zoom lens has the foremost or first lens group Gof positive refractivity, the second lens group Gof negative refractivity, the third lens group Gof positive refractivity, and the fourth lens group Gof positive refractivity disposed in sequence from a position closer to the object toward the image plane, and it meets requirements as defined in conditional formulae as follows:6</()<10where Lw is the entire length of the lens optics (i.e., from the front surface of the foremost lens piece to the image plane) at the wide-angle end, Ft is a focal length of the lens optics in whole at the telephoto end, and Fw is the focal length of the lens optics in whole at the wide-angle end.