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:
Oct. 22, 2013
Filed:
Jul. 13, 2011
Shinji Yamasaki, Utsunomiya, JP;
Shinichiro Saito, Utsunomiya, JP;
Shinji Yamasaki, Utsunomiya, JP;
Shinichiro Saito, Utsunomiya, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
A zoom lens comprising, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power. The second and third lens units are configured to move in an optical axis direction for a magnification variation, and the first lens unit is configured to move in the optical axis direction to reduce an image-plane fluctuation associated with the magnification variation. Expressions −0.83≦f/f≦−0.40 and −4.6≦f/fw≦−2.5 T are satisfied where fis a focal length of the first lens unit, fis a focal length of the second lens unit, and fw is a focal length of the entire zoom lens at a wide angle end.