Abstract:
A lens 1 has unevenness within an optical effective diameter D of an optical surface 2, an arithmetic mean roughness Ra within the optical effective diameter D of the optical surface 2 is 20 nm or more and 50 nm or less, and an average value of widths W of protrusion portions 3 of the unevenness on an average line C2 of a roughness curve C1 of the optical surface 2 is 1/200 or more and 1/50 or less of the optical effective diameter D of the optical surface 2. The lens 1 is suitably used as a lens that composes a zoom lens or an imaging lens.
Abstract:
A variable magnification optical system consists of, in order from an object side, a first optical system remaining stationary during changing magnification and a second optical system including a plurality of lens groups moving during changing magnification. The first optical system includes a first mirror and a second mirror having reflective surfaces arranged to face each other. The first mirror is an optical element having a power at a position closest to the object side on an optical path and has a reflective surface concave toward the object side. The second mirror has a reflective surface convex toward the image side. An intermediate image is formed between the second mirror and the second optical system.
Abstract:
The variable magnification optical system includes, in order from an object side, a positive first lens group disposed at a position closest to the object side, a variable magnification lens group which is disposed at a position closest to the object side among negative lens groups and moves during changing magnification, an intermediate group including at least one lens group, and a positive final lens group which is disposed at a position closest to the image side. The variable magnification lens group, the intermediate group, and the final lens group are continuously disposed. The variable magnification optical system includes at least one LA lens. This LA lens satisfies predetermined conditional expressions relating to a refractive index, an Abbe number, and a partial dispersion ratio, and is located from the variable magnification lens group to the intermediate group.
Abstract:
The imaging lens consists of a first lens group G1, an aperture stop St, and a positive second lens group G2, in order from an object side. The first lens group G1 consists of a 1-1st negative meniscus lens L11 with its convex surface toward the object side, a 1-2nd negative lens L12 with its concave surface toward an image side, a 1-3rd positive lens L13 having a biconvex shape, a 1-4th negative meniscus lens L14 with its convex surface toward the object side, and a 1-5th positive lens L15 with its convex surface toward the object side, in order from the object side. Predetermined conditional expressions are satisfied which relate to a focal length of the whole system, a focal length of the first lens group G1, and a distance on an optical axis between the 1-4th negative meniscus lens L14 and the 1-5th positive lens L15.
Abstract:
Provided are an imaging lens, which has a small F number and in which various aberrations are satisfactorily corrected, and an imaging apparatus including the imaging lens.The imaging lens includes, in order from an object side: a first lens that has a biconcave shape; a second lens that is convex toward an image side and has a positive refractive power; a third lens that has a biconvex shape; a fourth lens that has a negative refractive power; a fifth lens that has a positive refractive power; and a sixth lens that has a negative refractive power. Assuming that L1f and L1r are paraxial radii of curvature of an object side surface and an image side surface of the first lens, Conditional Expression (1) is satisfied. 0.1
Abstract:
An objective lens for endoscopes includes, in order from the object side: a front group; an aperture stop; and a positive rear group. The front group includes, in order from the object side, a negative first lens, in which the absolute value of the radius of curvature of the surface toward the image side is less than that of the surface toward the object side, and at least one plane parallel plate. The rear group includes, in order from the object side, a positive second lens, and a cemented lens formed by a positive third lens and a negative fourth lens. The coupling surface of the cemented lens is convex toward the image side. Conditional Formulae (1) through (3) concerning the plane parallel plates within the front group, the focal length of the first lens, the radius of curvature of the coupling surface of the cemented lens, etc., are satisfied.
Abstract:
A zoom lens is constituted by, in order from the object side: a positive first lens group; a negative second lens group; a positive third lens group; a negative fourth lens group; and a positive fifth lens group. The distance between the first and second lens groups constantly increases, the distance between the second and third lens groups constantly decreases, the distance between the third and fourth lens groups constantly changes, and the distance between the fourth and fifth lens groups constantly increases when changing magnification from the wide angle end to the telephoto end. The first lens group is constituted by three lenses, which are negative, positive, and positive in order from the object side. The second lens group is constituted by five lenses, which are negative, negative, positive, positive, and negative in order from the object side. The fifth lens group is constituted by a single lens component.
Abstract:
An imaging lens consists of, disposed in order from the object side, a front group, a stop, and a rear group, wherein the front group includes, in order from the most-object side, a positive first lens, a negative second lens, and a negative third lens which are adjacently disposed, the rear group consists of two sets of cemented lenses having positive refractive powers and a positive single lens, the object-side cemented lens is formed by cementing, in order form the object side, a positive lens with a convex surface toward the image side and a negative meniscus lens together, the image-side cemented lens is formed by cementing, in order from the object side, a negative meniscus lens with a concave surface toward the image side and a positive lens together, and the image-side cemented lens is disposed at the most-image side of the rear group.
Abstract:
An imaging lens is essentially constituted by seven lenses, including: a positive first lens having a convex surface toward the object side; a second lens, of which at least one surface is of an aspherical shape; a third lens, of which at least one surface is of an aspherical shape; a fourth lens, of which at least one surface is of an aspherical shape; a positive fifth lens of a meniscus shape with a convex surface toward the image side; a sixth lens, of which at least one surface is of an aspherical shape; and a negative seventh lens having a concave surface toward the image side, provided in this order from the object side. The imaging lens satisfies a predetermined conditional formula.
Abstract:
An imaging lens consists of a first lens group, a second lens group, an aperture stop and a third lens group that has positive refractive power in this order from an object side. The first lens group consists of an L11 lens having positive refractive power, an L12 lens having negative refractive power, an L13 meniscus lens having negative refractive power with its concave surface facing an image side, an L14 lens having negative refractive power with its concave surface facing the object side and two or three lenses, each having positive refractive power, in this order from the object side. The second lens group consists of an L2p lens having positive refractive power and an L2n lens having negative refractive power.