Abstract: A fast ultra-wide angle lens system is provided which includes a front lens group having a negative power, a diaphragm, and a rear lens group having a positive power, arranged in this order from a side of an object to be photographed. The lens system satisfies the following conditions:-0.5<f/f.sub.F <-0.2; (1)7.0<.SIGMA.d.sub.F+S /f<12.0; and (2)5.0<.SIGMA.d.sub.R /f<10.0, (3)wherein f represents a focal length of the entire lens system, f.sub.F represents a focal length of the front lens group, .SIGMA.d.sub.F+S represents a sum of the length of the front lens group and a distance between the front lens group and the rear lens group, and .SIGMA.d.sub.R represents a length of the rear lens group.

Abstract: A fisheye lens comprises sequentially from an object, a first lens group including a negative meniscus lens and a second lens group having positive refracting power. The first and second lens groups move on the optical axis toward the object. The fisheye lens incorporates a short distance compensating function for focusing from an infinity object point onto a short distance object point by expanding n air space between the first and second lens groups and further satisfies various conditions.

Abstract: An airspaced, diffraction limited, seven element telecentric f-theta lens having a first meniscus lens concave to the incident side; a first bi-concave lens; a second meniscus lens convex to the incident side; a third meniscus lens concave to the incident side; a pair of bi-convex lenses; and a second bi-concave lens is disclosed. The second, third and fourth as well as the sixth and seventh lens elements are edge contact spaced.

Abstract: An nonvariable transverse magnification focussing method and lens system for maintaining a transverse magnification at a fixed value even when the movement distance of each lens group is quite small by moving the basis of the first lens group and the second lens group while maintaining the relationship therebetween with a suitable paraxial arrangement in accordance with specific principles.

Abstract: An optical system is adapted to conjugate an object plane with an image spherical dome whose radius is less than its focal length and whose exit dioptric is a spherical dome on which the image spherical dome is substantially superimposed. The optical system can be used in an exposure device for modifying by physical-chemical treatment the power profile of an artificial optical lens made from a photopolymerizable material. The device comprises a source of radiation and between the source of radiation and the artificial optical lens to be irradiated a mask adapted to modulate the energy flux spatially. The exposure device comprises a curved field lens system formed by the optical system.

Abstract: An afocal lens assembly which includes a first and second lens group used r testing an infrared detector assembly. The first lens group includes three lens elements and the second lens group includes four lens elements. The output of the lens assembly includes up to a 60 degree collimated field-of-view. The lens elements are infrared transmissive.

Abstract: An apocromatic relay system suitable for use in a high definition telecine apparatus comprising two groups of lens components with approximate symmetry about an aperture stop, as in a basic double gauss configuration plus one or two additional lens components located at the front of the first group of lens components and/or at the rear of the second group.