Abstract: A lens system is provided. The lens system includes a first lens system moveable between a first position removed from an optical axis and a second position on the optical axis. The first lens system includes a first lens element, an aperture stop, and a second lens element positioned in order from an object side to an image side of the lens system. The first lens system has a first focal length. A second lens system is moveable between a first position on the optical axis and a second position removed from the optical axis. The second lens system has a second focal length with the second focal length being greater than the first focal length such that a magnification ratio change results from interchanging the first lens system and the second system on the optical axis.

Abstract: A two position variable focal length lens is provided. The variable focal length lens includes a common lens element moveably positioned on an optical axis; a wide angle lens element moveable between a first location removed from the optical axis and a first position on the optical axis on an image side of the common lens element; and a telephoto lens element moveable between a second location removed from the optical axis and a second position on the optical axis on the image side of the common lens element. A magnification ratio change is effected by moving the common lens element along the optical axis and switching between the wide angle lens element located at the first position on the optical axis and the telephoto lens element located at the second position on the optical axis.

Abstract: A two position variable focal length lens is provided. The variable focal length lens includes a common lens element moveably positioned on an optical axis; a wide angle lens element moveable between a first location removed from the optical axis and a first position on the optical axis on an image side of the common lens element; and a telephoto lens element moveable between a second location removed from the optical axis and a second position on the optical axis on the image side of the common lens element. A magnification ratio change is effected by moving the common lens element along the optical axis and switching between the wide angle lens element located at the first position on the optical axis and the telephoto lens element located at the second position on the optical axis.

Abstract: A zoom lens is provided. The zoom lens includes a positive power first lens group having a first lens element and a second lens element, and a negative power second lens group having a third lens element. The first lens element can be made from plastic having either or both of its surfaces aspheric with a meniscus shape concave or convex to an object side. The first lens group includes a variable iris having a mechanical aperture stop positioned between the first lens element and the second lens element.

Abstract: A lens component comprising a first plastic lens element having a thin glass coating and a second lens element cemented to the glass coated surface of the first plastic element.

Abstract: A water-resistant camera comprising a frame counter having successive numbered portions for indicating the particular number of exposures remaining for picture-taking, and an optical magnifier for transmitting ambient light beams to the frame counter to form an enlarged image of any one of the numbered portions in order to facilitate viewing the one numbered portion, is characterized in that the optical magnifier is positioned out of optical alignment with at the one numbered portion, and includes an optical wedge that bends the light beams the optical magnifier transmits to the frame counter in order to make the enlarged image of the one numbered portion appear to be optically aligned with the optical magnifier.

Abstract: An optical system comprising two lens elements one of which is biaspheric, the optical system is suitable for use in photographic devices such as single-use cameras having curved image planes. This optical system can operate at low F-numbers while maintaining an excellent performance.

Abstract: Manufacturing of a desensitized lens system including: i) providing a starting point lens design having a plurality of aspheric surfaces; ii) decentering the design parameters of one of the aspheric surfaces; iii) optimizing the lens design with a decentered aspheric surface parameter by utilizing both positive and negative field rays to come up with optimum parameters for aspheric surfaces; iv) dropping the decenter out when the optimization is complete to obtain the nominal lens system parameters.

Abstract: An optical system comprising two lens elements suitable for use in photographic devices such as single-use cameras having cylindrical image planes. This optical system can operate at F-numbers lower than F/11 while maintaining an excellent performance.

Abstract: A compact, simple real image finder includes an objective, a field lens, erecting optics and an eyepiece. The field lens is separated from an internal image sufficiently that it contributes substantially to the magnification of the finder.

Abstract: A recyclable single-use camera in which a front casing portion is separable from a main body portion to replace a taking lens during recycling of said camera, is characterized in that the taking lens has a front lens element and a rear lens element. The rear lens element is secured to the main body portion in order to prevent removal of the rear lens element. The front casing portion holds the front lens element in optical alignment with the rear lens element, and permits removal of the front lens element to allow it to be replaced whenever the front casing portion is separated from the main body portion during recycling of the camera.

Abstract: A zoom camera lens for an inexpensive camera, for example, a single use camera, has two plastic elements including a positive element and a negative element and a stop. Each of the surfaces of each of the elements is concave to the stop. Preferably, the lens has a curved image plane.

Abstract: A compact Galilean-type zoom finder suitable for compact cameras, and the like whose zoom ratio is about 2. The zoom finder is comprised of four units having negative, negative, positive and negative refractive powers in order from an object side and a movable framing window. The first and the fourth lens units are fixed and the second and the third lens units are moved to perform zooming. The moving framing window helps to delineate the field of view.

Abstract: A compact Galilean-type zoom finder suitable for compact cameras, and the like whose zoom ratio is about 2. The zoom finder is comprised of four units having negative, negative, positive and negative refractive powers in order from an object side and a movable fixed aperture framing window. The first and the fourth lens units are fixed and the second and the third lens units are moved to perform zooming. The moving framing window helps to delineate the field of view.

Abstract: A compact Galilean-type zoom finder suitable for compact cameras, and the like whose zoom ratio is about 2. The zoom finder is comprised of four units having negative, negative, positive and negative refractive powers in order from an object side. The first and the fourth lens units are fixed and the second and the third lens units are moved to perform zooming.

Abstract: An improved polymerization reactor apparatus having a vertically disposed outer shell, a liquid polymer inlet at the top of the shell and a liquid polymer outlet at the bottom of the shell, and a series of downwardly sloping trays for conducting a flow of the liquid polymer in a descending path from the inlet to the outlet; the series of trays being encompassed within a series of essentially rectangular pan assemblies supportedly spaced inwardly from the outer shell and by which pan assemblies the liquid polymer flow is divided into two separated flows of uniform flow cross-section, with vapor from the liquid polymer escaping along paths separated from interference with the liquid polymer flow paths from the open top of each pan assembly and through "windows" or openings in two of the opposite end walls of the pan assembly to the outer shell of the reactor apparatus.