Title:
LARGE-APERTURE WIDE-ANGLE LENS
Document Type and Number:
Japanese Patent JP2018018041
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a large-aperture wide-angle lens which offers a wide view angle, small F-number, large aperture, and sufficient back focus, and yet is well corrected for various aberrations and provides high optical performance.SOLUTION: A large-aperture wide-angle lens of the present invention comprises a first lens group G1, an aperture stop S, and a second lens group G2 having positive refractive power arranged in order from the object side to the image side, the first lens group G1 having a first negative meniscus lens with a convex surface facing the object side located on the most object side. The large-aperture wide-angle lens has a first aspherical surface AS1 on an object-side surface of the first negative meniscus lens, has a second aspherical surface AS2 on a surface of a lens located on the image side of the first negative meniscus lens, and satisfies predefined conditions.SELECTED DRAWING: Figure 1
Inventors:
SATO RYOSUKE
KAMIMURA YUTAKA
KAMIMURA YUTAKA
Application Number:
JP2016150744A
Publication Date:
February 01, 2018
Filing Date:
July 29, 2016
Export Citation:
Assignee:
SIGMA CORP
International Classes:
G02B13/04; G02B13/18