Abstract: A lenslet array system includes (i) a first assembly including a field-limiting mask and a first lenslet array having an associated focal plane and (ii) a second assembly including a second lenslet array accepting light from the first assembly. The first lenslet array accepts a full field of view in excess of 20 degrees and forms a plurality of image sections of the associated object on an intermediate image plane which is substantially coplanar with the focal plane associated with the first lenslet array. The first lenslet array includes a plurality of positive power lenslets. Each of the plurality of lenslets has a focal length f.sub.1 of less than 15 mm and accepts a unique segment of the full field of view subtended by the associated object. These segments of the full field of view together comprise the full field of view, and each of said lenslets forms one image section corresponding to its segment of the full field of view.

Abstract: An improved hybrid camera is provided for capturing an image photographically on film and electronically on an electronic sensor in which the image captured by the electronic sensor may be electronically cropped to match the image captured on the film. The camera includes a first lens having multiple focal lengths and a second lens having two selectable focal lengths. The image is focused through the first lens onto the film to capture the image photographically, while the image is focused through the second lens on an electronic sensor to capture at least the image electronically. A controller in the camera selects the focal length of the second lens to maximize the resolution of the portion of the image captured on the electronic sensor which matches the image captured on the film. The image captured on the electronic sensor may be cropped by the controller to match the image captured on the film.

Abstract: A lenslet array system for imaging an associated object onto a final image plane includes (i) a first lens assembly including a field limiting mask and a first lenslet array having an associated image plane, (ii) a second assembly including a rear lenslet array, and (iii) a middle lenslet array located between the first and said rear lenslet array. The first lenslet array accepts a full field of view subtends by the associated object and forms a plurality of image sections of the associated object on an intermediate image plane. The first lenslet array includes a plurality of positive power lenslets, each of the plurality of lenslets having a focal length f.sub.1 and accepting a unique segment of the full field of view subtended by the associated object. These segments of the full field of view together comprise the full field of view, and each of the lenslets forms one image section corresponding to its segment of the full field of view. The rear lenslet array has a plurality of positive power lenslets.

Abstract: A lens system comprises, in order from a first side to a second side four lens elements. They are: a first, positive power lens element having its convex surface oriented towards the first side; a second, negative power lens element; a third, meniscus lens element having its concave surface oriented towards the first side; and a fourth, meniscus lens element having its concave surface oriented towards the second side.

Abstract: A lens system has nominal focal length and aberrations and includes a plurality of lens components defined by design parameter values and a special airspace distance. The lens system is characterized in design such that manufacturing deviations from the design parameter values cause a variation from the nominal focal length and a variation in at least one of the aberrations. Both of these deviations can be offset simultaneously by a single change in the special airspace distance.

Abstract: Diffractive optics using surface relief profiles, also known as blazed gratings having ramps and edges or steps (also referred to as blazed facets with discontinuities at the interfaces between adjacent facets) defining grating lines and phase delays to which light propagating through the grating are subject. Diffractive lenses which are known as phased Fresnel zone plate lenses or kinoforms, also have annular blazed facets with discontinuities, steps at the interface between adjacent facets at the steps which facets define the zones of the lens. These steps are either aligned parallel to the light incident on the grating or coated with an optically opaque material, thereby preventing the transmission of incident light which is not diffracted, but would be scattered or transmitted at the steps. The contrast and quality of an image provided by the diffractive lens at a plane spaced from the grating, which may be the focal plane of the diffractive lens, is therefore enhanced.

Abstract: A lenslet array system for imaging an associated object onto a final image plane includes (i) a first assembly including a baffle structure and a first lenslet array having an associated image plane and (ii) a second assembly including a second lenslet array.The first lenslet array accepts a full field of view subtends by the associated object and forms a plurality of image sections of the associated object on an intermediate image plane. The first lenslet array includes a plurality of positive power lenslets, each of the plurality of lenslets having a focal length f.sub.1 and accepting a unique segment of the full field of view subtended by the associated object. These segments of the full field of view together comprise the full field of view, and each of the lenslets forms one image section corresponding to its segment of the full view.

Abstract: A lens system particularly suitable for use in a camera using small format film has two lens units, a front negative power lens unit and a rear positive power lens unit. The rear lens unit has no negative lens elements and includes an aspheric surface and a diffractive surface.

Abstract: An improved tool is provided for pressing glass into a precision optical element having a strong concave surface. The tool is selected from ceramic and metal materials having coefficients of thermal expansion greater than the coefficient of the pressed glass. Preferred tools include a base material selected from Invar, steel and alumina with a surface layer selected from alumina, zirconia, chromium oxide and chromium carbide, having a finished thickness in the range between ten to two thousand angstroms.

Abstract: A diffractive optical element, ("DOE"), and particularly a diffractive lens having annular zones about an optical axis and known as a Fresnel zone plate or kinoform lens, is athermalized so that its effective focal length ("EFL") does not shift substantially with temperature over a temperature range by, respectively, increasing and decreasing the zone widths with respect to widths which are optimized to focus at the EFL at room temperature. Half of the zones (alternate, adjacent zones) provide the correct EFL for the expanded condition of the lens at the hot end of the temperature range; the other half of the zones provide correct EFL for the contracted condition of the lens at the cold end of the temperature range.

Abstract: A cluster lens for imaging a transparency onto an image plane comprises a plurality of lenses which simultaneously have a field of view sufficient to include the transparency. All of the lenses image simultaneously. At least two of these lenses have different magnifications. The lenses are located in a spaced relationship to each other so that that not one of these lenses encroaches upon that section of the field of view of another lens that is used to image the transparency onto the image plane.

Abstract: A catadioptric lens system may be operated in the telephoto mode to allow images of distant objects to be formed with large image plane magnification and be part of a camera body wherein a rear reflective section of the catadioptric lens system is provided by a front face of the camera body which has a clear aperture centered about the optical axis. An image is focused at the film plane. The catadioptric lens system has a diffractive/refractive hybrid singlet lens which corrects off-axis aberrations and decreases the overall lens length. The front surface of the lens defines an asphere. The back surface has a diffractive lens with annular blazed zones. The back surface also has an inner portion which is reflective and may have the same curvature as the transmissive section of the singlet (the back surface base curve of the from which the blazed zones extend). The lens system provides catadioptric imaging (sometimes called contracurrent or katoptric imaging) at the film plane.

Abstract: A wide angle zoom lens suitable for use in cameras for providing sufficiently wide range of field angles to cover a frame of a film in the camera provides performance comparable to zoom lenses having more elements. The wide angle zoom lens has four elements in three groups which are moveable with respect to each other. The front group has a diffractive lens formed on a curved surface thereof. The second or intermediate group and the front group has surfaces are aspheres for aberration correction as does a surface of a single element third group. Chromatic aberration is corrected by the diffractive lens in combination with the lens of the other groups over the zoom range. The third group lens is formed with glass with lower dispersion (higher Abbe number) than the lenses of the other groups. The second group has two lenses one of which may be a low power, negative, meniscus lens which is made of plastic thereby further reducing the cost of the zoom lens.

Abstract: A lenslet array system for imaging an associated object onto a final image plane includes (i) a first lens assembly including a field limiting mask and a first lenslet array having an associated image plane and (ii) a second assembly including a second lenslet array accepting light from said first lenslet array. The first lenslet array accepts a full field of view in excess of 20 degrees and forms a plurality of image sections of the associated object on an intermediate image plane. The first lenslet array includes a plurality of positive power lenslets, each of the plurality of lenslets having a focal length f.sub.1 and accepting a unique segment of the full field of view subtended by the associated object. These segments of the full field of view together comprise the full field of view, and each of the lenslets forms one image section corresponding to its segment of the full view. The second lenslet array of the second assembly accepts light from said first assembly.

Abstract: A rear attachment is provided to permit objective lens systems designated for a certain image format to be used for imaging on a smaller image format. Thus, a 35 mm single lens reflex camera lens can be used to create an image on a smaller format CCD array.

Abstract: A compact zoom lens with three lens units of positive, positive and negative optical powers, respectfully. The front and the rear lens units move together for zooming and the middle unit moves independently. There is one aspheric surface in each of the three lens units. An aperture stop is located with the front lens unit.

Abstract: An enlargement lens system with a large working distance comprising five lens components with a stop between the third and fourth components (numbered from the long conjugate side). It includes a first negative lens component, meniscus concave to the stop; a second positive lens component, having a convex surface toward the first lens component; a third and fourth lens component, both cemented negative doublets, meniscus concave to the stop; and a fifth positive power biconvex lens component, wherein BF/EF>1.0, where BF is the short conjugate back focus and EF is the focal length of the lens system.

Abstract: In order to reduce complexity and cost of fabrication of zoom lenses, the real image forming lens group module at the front of the zoom lens is replaced with a two-element group where one of the elements has a diffractive lens on a curved surface thereof instead of the usually cemented doublet of the front group, but with substantially the same aberrations as a front group with three elements, including a cemented doublet. Aberrations (chromatic and monochromatic) produced by the first and second groups remain corrected by the combination of these groups over the zoom range of the lens. A second group housing two-elements, one of which has a curved surface on which a diffractive lens is provided, may be also be used to replace the three-element second lens group and particularly the cemented doublet thereof.

Abstract: A compact zoom lens with three movable lens units of positive, positive and negative optical powers, respectfully. During zooming, the axial distance between the first and the rear lens units changes less than the axial distance between the first lens unit and the middle lens unit; the middle lens unit is movable towards the object side at a relatively slower axial speed than that at which the first and third lens units are moved.

Abstract: A viewfinder having an optical axis and comprising a negative lens component including a lens element having a first diffractive surface which introduces a phase modification .phi.(r) into a light wavefront passing through this diffractive surface and a positive lens component receiving phase modified light from the negative power lens component.