摘要:
An imaging lens unit comprising, in order from the object side, a first lens having a meniscus shape with its convex surface on the object side, an aperture stop and a second lens having a meniscus shape with its convex surface on the image side. A maximal value of a tangent angle within a range of a lens surface effective diameter of the surface on the object side of the first lens is 70 to 90 degrees. A maximal value of a tangent angle within a range of a lens surface effective diameter of the surface on the image side of the second lens is 70 to 90 degrees.
摘要:
Providing an optical system having excellent optical performance over entire focusing range from infinity to a close distance, a method for focusing the optical system, and an imaging apparatus equipped therewith. The optical system includes, in order from an object, a first lens group G1 having positive refractive power, and a second lens group G2 having positive refractive power. The second lens group G2 is movable along an optical axis for varying focusing. The first lens group G1 satisfies a given conditional expression.
摘要:
A lens system has a plurality of lenses, a stop, and a diffractive surface, the entire lens system moves during focusing, and the lens system satisfies the condition of β≧0.5, where β is a maximum photographic magnification.
摘要:
A description is given of a photographic objective of the modified double gauss type having a front group, comprising of three lens elements (L1, L2, L3) and having the refractive power sequence ++−, an aperture and a rear group including lens elements (L4, L5, L6) of refractive power sequence −++, which is distinguished in that in the rear group the lens element of negative refractive power (L4) is designed as a meniscus with an aspheric surface concave relative to the aperture, and a lens element of negative refractive power (L7) with surfaces concave on both sides is arranged downstream of the last lens element of positive refractive power (L6).
摘要:
A photographic lens has a first and second positive lens. The first lens is a meniscus lens having a convex object side surface. The second lens is a double-convex lens. The photographic lens satisfies the following conditions: 5.6≦f F2; 0.39 |R4| wherein F is an overall focal length, F1 is a focal length of the first lens, F2 is a focal length of the second lens, f is a ratio of the overall focal length F to an effective aperture size defined by the first stop, R1 is a radius of curvature of the object side surface of the first lens, R3 and R4 are radii of curvature of the object side spherical surface and of an average spherical surface of the image side aspherical surface of the second lens.
摘要:
A lens for image pickup is provided in which various aberrations are corrected satisfactorily, the optical length is at maximum approximately 6 mm, and moreover a sufficient back focus is secured. This lens for image pickup comprises a first lens, an aperture diaphragm, and a second lens, positioned in this order from the object side toward the image side. The first lens is a resin lens with a meniscus shape, with the convex surface facing the object side, and having positive refractive power. The second lens is a resin lens with a meniscus shape, with the convex surface facing the image side, and having positive refractive power.
摘要:
A standard photographic lens is disclosed that includes a front lens group, a diaphragm stop, and a rear lens group, in order from the object side. The front lens group is formed of a negative meniscus lens with its convex surface on the object side, and a positive meniscus lens with its convex surface on the object side. The rear lens group is formed of a third lens element of negative refractive power with a concave surface on the object side, a fourth lens element of positive refractive power with a convex surface on the image side, and a fifth lens element, of meniscus shape with its concave surface on the image side. Organic material is preferably used for the second and third lens elements. Various conditions are satisfied so as to provide a lens having a bright image with favorably corrected aberrations.
摘要:
A projection lens for use with a pixelized panel (LCD) is provided. The lens has two positive lens units with an aperture stop between them. The optical powers of each of the units are such that f1 is substantially shorter than f2, where f1 and f2 are the focal lengths of the first lens unit and the second lens unit, respectively, the first lens unit being on the system's long conjugate side and the second lens unit being on the short conjugate side. The ratio of f1 to f2 is preferably less than about 0.75.
摘要:
Provided is a color-image-reading Gaussian lens for reading out color images, color originals, or negative or positive films, which is suitably used at a low magnification of -1/2.5.times. to -1/1.25.times., effectively corrects axial chromatic aberration in particular, and exhibits high performances in a wide wavelength range. A six-sheet Gaussian lens comprises, successively from an object side, two convex lenses, two concave lenses, and two convex lenses, while a stop is disposed between the two concave lenses. In particular, the following conditional expressions are satisfied:0.10
摘要:
A lens system particularly suitable for use in a camera using small format film has two lens units, a front negative power lens unit and a rear positive power lens unit. The rear lens unit has no negative lens elements and includes an aspheric surface and a diffractive surface.