WIDE-ANGLE LENS

摘要

A wide-angle lens may include a first lens having negative power; a second lens being a plastic lens having negative power, wherein at least one of an object side lens face and an image side lens face is an aspherical surface; a third lens being a plastic lens having negative power, wherein at least one of an object side lens face and an image side lens face is an aspherical surface; a fourth lens having positive power; a fifth lens being a plastic lens; a sixth lens being a plastic lens, wherein the fifth lens and the sixth lens constitute a cemented lens having positive power; and a diaphragm disposed between the fourth lens and the cemented lens. The effective focal length “f” and the focal length “f3” may satisfy the relationship: |f/f3|<0.2.

主权项

1. A wide-angle lens whose horizontal viewing angle is 130° or more and which has a lens constitution of six lenses in five groups, the wide-angle lens comprising:
a first lens arranged first from an object side and is a plastic lens or a glass lens having negative power with a convex surface facing the object side and a concave surface facing an image side; a second lens arranged second from the object side and is a plastic lens having negative power with a concave surface facing the image side, wherein at least one of an object side lens face and an image side lens face is an aspherical surface; a third lens arranged third from the object side and is a plastic lens having negative power with a concave surface facing the object side, wherein at least one of an object side lens face and an image side lens face is an aspherical surface; a fourth lens arranged fourth from the object side and is a plastic lens or a glass lens having positive power with a convex surface facing the image side; a fifth lens arranged fifth from the object side and is a plastic lens; a sixth lens arranged sixth from the object side and is a plastic lens, wherein the fifth lens and the sixth lens constitute a cemented lens having positive power; a diaphragm which is disposed between the fourth lens and the cemented lens; wherein when an effective focal length is “f” and a focal length of the third lens is “f3”, the effective focal length “f” and the focal length “f3” satisfy a following relationship;
|f/f3|<0.2