Vivitar Corporation

Ponder & Best, Inc.

Opcon Associates of Canada, Ltd.

Minnesota Mining and Manufacturing Company

U.S. Precision Lens Incorporated

Optigon Research & Development Corporation

Fimacon Associates

Ellis I Betensky

John A Lawson

A three element lens particularly adapted to project an image appearing on a cathode ray tube.

Projection lens

A zoom lens having a wide field angle and two movable groupings to vary the equivalent focal length, the front grouping comprising a front positive group, a negative group comprising a plurality of negative elements, and a rear positive group. In zooming the rear grouping moves forward to increase the equivalent focal length while the front grouping moves backward to maintain the image plane. The front grouping is independently movable for focusing.

Zoom lens

A zoom lens having a semi-field angle of between 12.6.degree. and 6.3.degree. capable of focusing at a 1:2 image-to-object distance ratio while providing a comfortable working range. The lens comprises a movable focusing group, a second stationary compensating group, two zooming groups which move axially relative to the lens and differentially of each other, and a fifth rear master group.

A three element lens comprising two outer positive meniscuses and a central negative meniscus with all three elements concave to the aperture stop between the negative meniscus and a positive element.

Triplet with aspheric surfaces

This disclosure relates to a Wide Angle Lens of the retrofocus type having a new lens group arrangement which comprises from the object end to the image end a first negative group, a second negative group in the form of a meniscus having a concave image side surface, a third positive group having a convex object side surface, a fourth positive group having a convex image side surface, a fifth negative group, and a sixth positive group having convex image and object side surfaces.

Wide angle objective

A magnifier or loupe of high magnifying power comprising a positive singlet followed by a cemented doublet in the overall form of a meniscus having bi-convex and bi-concave elements. The cemented surfaces, the outer surfaces of the doublet, or both may be made aspheric.

Loupe

A continuously variable anamorphic lens containing two sets of four elements between which is placed two achromatized prisms. The anamorphic magnification is varied by the tilting of the prisms.

Continuously variable anamorphic lens

In a continuous path enlarger having an illumination system for illuminating a very wide continuously moving original and projecting the image thereof onto a much wider sheet of light sensitive recording material moving synchronously with the original, the improvement wherein the illumination system includes a plurality of identical abutting, illumination sources each having a light source and a lens system with the final lens thereof being in the shape of a parallelogram having straight side edges in contact with the adjacent side edges of each adjacent final lens, and with the side edges being at an acute angle to the direction of travel of the recording sheet. Further, the plurality of image areas on the recording sheet preferably overlap each other. Thus, the total amount of light received at any point on the recording sheet passing through an angled edge of one of the plurality of image areas integrates across the width of the exposure area and is sufficient to effect proper exposure of the recording material so that uniformity is achieved over the field of exposure.

Illumination system for continuous path enlarger

A lens having an equivalent focal length variable between predetermined limits where the lower limit is less than the diagonal of the image frame and where the lens comprises four lens groups of positive, negative, negative and positive powers, respectively, and the first three groups mounted from the object end are movable in unequal relationship to vary the focal length while all four groups are axially movable in fixed relation to each other to focus the lens.

A lens for a small film format still camera which comprises four lens elements disposed behind the aperture defining means, and includes a double convex convergent lens element, a second double concave divergent lens element, a third double convex convergent element, and a fourth concave-plano lens element.

Lens

A telephoto photographic lens having internal aberration compensation and comprising an objective which is movable for focusing and a rear lens which is stationary with respect to the film plane. The rear lens has an equivalent focal length greater than that of the overall lens and may have negative power which presents a slight change in the equivalent length of the overall lens when the lens is close focused.

Telephoto lens

A wide aperture long focus photographic lens having internal aberration compensation and comprising an objective which is movable for focusing and a rear lens which is stationary with respect to the film plane and has an equivalent focal length which is substantially longer than the equivalent focal length of the overall lens.

Growing community of inventors

Toronto, Canada

Ellis I Betensky