Minolta Camera Kabushiki Kaisha

Haruo Abe

Kayoshi Tsujimoto

Mitsuo Yasukuni

Tohru Matsui

Mitsuaki Horimoto

Teruo Hosokawa

Masaichiro Konishi

An optical lens system is provided having the capability of selectively varying the peripheral field curvature to improve focusing for nonplanar objects and for special photographic effects. The lens system can include in sequence, a first lens group of positive refractive power, a second lens group of negative refractive power and a third lens group of positive refractive power. The specific refractive power of the first and second lens group are designed so that the optical ray traces from an object on the optical axis at infinity will run approximately parallel with the optical axis in the space between the second and third lens groups. The first and second lens groups being movable as a unit relative to the third lens group to change the field curvature without varying the back focal distance of the lens system.

Variable field curvature lens system

The present lens system is capable of providing both a zooming operation and also a relatively efficient and economical macrophotography mode of operation. The zoom lens system contains the basic conventional lens groups of a focusing lens group, variator lens group, compensator lens group and relay lens group. These individual lens group function in a conventional manner during a zooming mode of operation. However, during the macrophotography mode of operation, the individual lens element that form the relay lens group are capable of coordinate movement with other lens elements in the lens system to provide a relatively compact and economical lens design for macrophotography. Thus, the relay lens group is not only capable of performing its normal auxiliary function of image transmission and final balancing of aberrations imposed by the design parameters of the zoom mode of operation but is further capable of compensating for the introduction of aberrations that will occur in the macrophotography mode of operation. In some embodiments, the plurality of movable lens elements that form the relay lens group has at least that movable lens element closest to the design image plane moved to provide the second macrophotography mode of operation.

Zoom lens system capable of macrophotography

A varifocal lens assembly of a type including at least two lens groups, a first lens group being axially movable parallel to the optical axis of the varifocal lens assembly for varying the focal length of the optical system of the varifocal lens assembly. An automatic focusing device is associated with the varifocal lens assembly to axially move the lens groups as a whole, the other or second lens group or a part of lens elements of the other or second lens group a predetermined distance to compensate for the image shift which takes place during the adjustment of the focal length effected by axially moving the first lens group.

Varifocal lens assembly

An optical system in a single or double tube color television camera for minimizing color shading, moire patterns and color beats includes along the image optical axis a phase grating low pass filter, a color encoding filter and a lenticular lens member oriented relative to each other and the image scanning to minimize interference between the color encoding filter and striped patterns in the viewed object. The color encoding filter is striped, the low pass filter is either striped or has regularly longitudinally and transversely spaced phase retarding projections and the lenticular lens member includes transversely spaced longitudinal cylindrical lenses or regularly transversely and longitudinally spaced convex projections.

Growing community of inventors

Sakai, Japan

Haruo Abe