摘要:
A variable focal length objective of which at least one of a pulrality of lens units is moved to vary the image magnification, wherein at least one of the plurality of lens units has at least one refractive index distribution type lens provided with a condition of N.sub.1 >0 as, taking the distance from the optical axis to a radial direction as h, the refractive index distribution is expressed by N(h)=N.sub.0 +N.sub.1 h.sup.2 +N.sub.2 h.sup.4 +N.sub.3 h.sup.6 +. . . (N.sub.0, N.sub.1, N.sub.2 . . . are constants), and satisfies the following conditions: ##EQU1## where fmax: the maximum focal length;fmin: the minimum focal length;Lmin: the optical total length when the total length is shortest;Y: the maximum image height;N.sub.1 *: the coefficient of h.sup.2 of the refractive index distribution type lens having a refractive index distribution of N.sub.1 >0;D*: the lens thickness of the refractive index distribution type lens having the refractive index distribution of N.sub.1 >0.
摘要:
A zoom lens comprising a plurality of lens units in which at least one of the air separations between the units is varied to effect zooming, whereby at least one of the plurality of lens units is included with at least one refractive index distribution type lens element on a common optical axis of the other elements.
摘要:
An objective of variable focal length includes a plurality of lens units of which the first, counting from front, is of negative power and the second is of positive power. At least the first and second lens units are moved with variation of the air separation therebetween to vary the focal length of the entire system. The objective is characterized in that at least one of the lens units is included with at least one refractive index distribution type lens arranged on the common optical axis of the other lenses.
摘要:
A variable focal length objective having a plurality of lens units with at least one unit separation being varied to vary the focal length of the entire system, in which at least one of the plurality of lens units has at least gradient-index lens having a refractive index distribution of the form: N(h)=N.sub.0 +N.sub.1 h.sup.2 +N.sub.2 h.sup.4 +N.sub.3 h.sup.6 + . . . where h is the height from the optical axis, N.sub.0 is the refractive index on the optical axis, and N.sub.1, N.sub.2, N.sub.3, . . . are constants, satisfying the following conditions:.phi..sub.G .multidot.N.sub.1
摘要:
A lens system has a lens unit comprising a positive lens and a negative lens. The positive lens has an index distribution in the direction of the optic axis. The value of the index gradient for a light having a short wavelength in the vicinity of the vertex of at least one convex surface of the positive lens is smaller than the value of the index gradient for a light having a long wavelength.
摘要:
A zoom lens including at least two lens units of which the front one is of positive refractive power and the rear one is of negative refractive power, the units being axially movable to decrease their separation in zooming from the wide angle to the telephoto end. At least one of the lens units is provided with at least one refractive index distribution type lens arranged on a common optical axis of the other lenses in order to achieve a great advance in compactness.
摘要:
A zoom lens comprising, from front to rear, a positive first lens component, a negative second lens component, a positive third lens component and an image forming or fourth lens component, wherein as zooming occurs from the wide angle to the telephoto position, the first and third lens components are moved axially forward, while the second lens component is held stationary. By giving appropriately specified ranges for numerical values of the focal lengths of the first to third lens components, improvements in the compactness are achieved while still permitting good correction of aberrations.
摘要:
A refractive index distribution type meniscus-shaped single lens characterized in that it has a refractive index distribution in which the refractive index decreases along the optic axis thereof from a convex surface to a concave surface and the difference .DELTA.N in refractive index between the convex surface and the concave surface on the optic axis satisfies .DELTA.N.gtoreq.0.15.
摘要:
The disclosed variable magnification finder includes, from front to rear, a first lens unit of negative power, a second lens unit of positive power, a third lens unit of positive power, the first, second and third lens units constituting an objective lens of positive power, and an eyepiece of positive power. The first and second lens units form a finder image on a plane just in front of the third lens unit. The second lens unit is moved axially forward to increase the image magnification, while the shift of diopter of the finder is simultaneously compensated for by moving the first lens unit.
摘要:
An optical system comprising a plurality of lens components, wherein at least one of the components is a convex lens and has a radial gradient of refractive index in such a cross section that the refractive index increases toward the margin, so that it behaves as a lens of negative power.