Abstract A zoom lens assembly particularly adapted to be utilized in a copier apparatus and which comprises two moving groups, each having four optical elements that move in a manner to form a high-quality optical image over the magnification range of approximately -1.008 to -0.65. The lens assembly is achromatic over the spectrum from 4050A to 5900A. The object image distance is fixed and remains constant. The front movable group comprises a negative meniscus member convex to the front, a second negative meniscus member spaced from said first meniscus member, a third negative meniscus member convex to the front spaced from said second negative meniscus member, and a positive meniscus member convex to the front spaced from said third negative meniscus member. The second movable group comprises a durable convex member, a double concave member spaced from said double convex member and a doublet comprising a double concave member having a double convex lens cemented thereto.
A zoom lens assembly substantially achromatic over the spectrum from about 4050A to about 5900A comprising an axially movable front lens group and an axially movable rear lens group, each lens group comprising four elements, the front movable lens group comprising, from the front to the rear, a first negative meniscus element convex to the front, a second negative meniscus element convex to the front, a third negative meniscus element convex to the front and a positive meniscus element convex to the front, the rear movable lens group comprising, from the front to the rear, a double convex element, a double concave element, and a doublet, said doublet comprising a double concave element the rear surface of which is cemented to a double convex element.
Claim 2
Dependent Claim
125 words
A zoom lens assembly substantially achromatic over the spectrum from about 4050A to about 5900A comprising an axially movable front lens group and an axially movable rear lens group, each lens group comprising four elements, the front movable lens group comprising, from the front to the rear, a first negative meniscus element convex to the front, a second negative meniscus element convex to the front, a third negative meniscus element convex to the front and a positive meniscus element convex to the front, the rear movable lens group comprising, from the front to the rear, a double convex element, a double concave element, and a doublet, said doublet comprising a double concave element the rear surface of which is cemented to a double convex element.
Claim 3
Dependent Claim
14 words
A zoom lens assembly made substantially according to the following chart of constructional data.
Claim 4
Dependent Claim
14 words
A zoom lens assembly made substantially according to the following chart of constructional data.