US 4,830,477 A · Zoom lens capable of obtaining focal lengths beyond a variable focal length range

Abstract

A zoom lens comprising, from front to rear, a first zoom section and a second zoom section, the first zoom section having a plurality of movable lens units which simultaneously move to effect zooming, and the second zoom section having a plurality of axially movable lens units, the light beam exiting from the rearmost unit in the first section enters directly the frontmost unit in the second section, and the refractive powers of the front and rear lens units are made positive and negative respectively, whereby the front and rear lens units are simultaneously moved in such a way that the magnifying power of the rear lens unit remains positive when the focal length of the entire system varies.

Claims14

Dependent claims

A zoom lens comprising:

(a) a first zoom section having a plurality of movable lens units which simultaneously move along an optical axis to effect a first zooming;
and
(b) a second zoom section arranged in rear of said first zoom section and including a front lens unit of positive refractive power and a rear lens unit of negative refractive power successively which move along the optical axis to effect a second zooming,
wherein said front and said rear lens units are simultaneously moved in such a way that the image magnification of the rear lens unit remains positive in the entire range of movement of said front and rear lens units.

1 more element

Dependencies are inferred from the claim text.

Zoom lens capable of obtaining focal lengths beyond a variable focal length range

Life of this patent

Zoom lens capable of obtaining focal lengths beyond a variable focal length range

Life of this patent

Abstract

Claims14