Abstract: A zoom lens system comprising from front to rear a first lens group of negative power and a second lens group of positive power with the axial separation therebetween being variable for zooming purposes. The first lens group is provided with a non-spherical surface to achieve minimization of the overall dimensions of the complete system without causing any decrease in the extent to which the corrections of various aberrations are maintained throughout the zooming range irrespective of a great increase in the photographable range extended toward the wide angle side.

Abstract: In a zoom lens consisting of a first lens group having a negative refractive power and a second lens group having a positive refractive power with the air separation between the first and second groups being variable for zooming, there are provided two non-spherical surfaces positioned respectively in the first lens group and on the image side of a diaphragm in the second lens group at optional locations to prevent deterioration of aberrations which occurs when the image angle of the zoom lens is increased.

Abstract: In a variable focus objective an axial air space between a negative front lens and a positive rear lens component is variable for zooming. The first component is movable for focusing independently of the rear component and provided with a variable air space defined therein to facilitate focusing down to short object distances while preserving high grade imagery for close objects throughout the zooming range and assuring a good uniformity of image quality throughout the entire image region even at the full open aperture.

Abstract: In a diaphragm device for use in an optical instrument such as a camera and having two or more diaphragm blades movable across an imaging path of rays and arranged in axially displaced relation from each other to define a common aperture of variable size, there is provided means formed in a portion of at least one of the diaphragm blades to substantially either eliminate or reduce the axial displacement between the diaphragm blades at a relatively small aperture region, whereby the distribution of light energy is made uniform over the entire area of the image.

Abstract: A stabilized optical system consisting of an afocal front inverted Galileian telescopic system section and a relay rear lens system section, said telescopic system being designed to incorporate a plano-convex or plano-concave lens element of forward convexity or forward concavity as the rearmost lens element movable relative to the other lens elements. The rearmost lens element being held in fixed spatial alignment with an original line of sight axis by means of a substantially free gyro coupled thereto, while the remaining lens elements are secured in fixed relation to the housing of an instrument containing the optical system in coaxial alignment with the relay lens for jiggling about the center of curvature of the rearmost lens element. Thus accidental displacement or motion of the housing relative to the original line of sight axis can be exactly compensated to provide for stationary optical images inasmuch as the equation M = N - 1 is satisfied.

Abstract: A zoom lens system comprising an afocal front lens assembly and an image forming rear lens assembly is provided with stabilized optical means arranged in the optical path between said front and rear lens assemblies. When zooming, the stabilized optical means is controlled in accordance with the variation of angular magnification of the front lens assembly and with the deviation of the housing incorporating the zoom lens system from an original line of sight. The image is thus stabilized at the focal plane thereof against such deviation by varying the deflecting angle of the exiting light axis from the stabilized optical means with respect to the entering light axis. In one embodiment of the present invention, the rear lens assembly includes one or more members movable for zooming in such a manner that the zooming operation of the front lens assembly is consecutively followed by the zooming operation of the rear lens assembly, or vice versa.

Abstract: An image stabilized system comprising an afocal telescopic system section, deflecting means and a relay lens system section arranged in this order from the front, said deflecting means including a plano-convex and a plano-concave lens mounted in mating rotatable relation to each other, one of which is fixedly secured to the instrument housing containing the optical system in coaxial alignment with said telescopic system and relay lens system, and the other is held in fixed spatial alignment with the original line of a sight axis by means of a gyro stabilizer coupled thereto, thereby provide for stabilization of an image at the focal plane against accidental angular displacement or motions of the instrument relative to the original line of sight axis.