Abstract: There is provided a display method including acquiring first information representing a three-dimensional shape of a room including a projection surface onto which a first image is projected, displaying, based on the first information, a second image showing the three-dimensional shape of the room by a display device, acquiring second information which defines a projection range of the first image in the projection surface by receiving operation for designating the projection range, and displaying, by the display device, and based on the first information and the second information, third information superimposed on the second image indicating at least one of a number of one or a plurality of projectors disposed in the room in order to project the first image in the projection range, a model of the one or the plurality of projectors, or a setting position in the room of the one or the plurality of projectors.

Abstract: An inner-focusing type super wide-angle zoom lens system consisting of two lens groups, a negative lens group and a positive lens group, with the maximum angle of view of more than 100° and the zoom ratio of 1.7 or more is provided. The zoom lens system includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. Zooming operation is carried out by changing the interval between the first lens group G1 and the second lens group G2. The second lens group consists of, in order from the object side, a front second lens group G2a having a positive refractive power and a rear second lens group G2b having a positive refractive power. Focusing operation from infinity to near object is carried out by moving the front second lens group G2a to the image side. Predetermined conditional expressions are satisfied.

Abstract: An inner-focusing type super wide-angle zoom lens system consisting of two lens groups, a negative lens group and a positive lens group, with the maximum angle of view of more than 100° and the zoom ratio of 1.7 or more is provided. The zoom lens system includes, in order from the object side, a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power. Zooming operation is carried out by changing the interval between the first lens group G1 and the second lens group G2. The second lens group consists of, in order from the object side, a front second lens group G2a having a positive refractive power and a rear second lens group G2b having a positive refractive power. Focusing operation from infinity to near object is carried out by moving the front second lens group G2a to the image side. Predetermined conditional expressions are satisfied.

Abstract: Compact, low-cost keplerian variable-magnification viewfinders are disclosed that have a zoom ratio of at least 2 and simple composition that favorably corrects all aberrations. The viewfinders are useful for use with various types of cameras, and comprise a positive objective lens system and a positive ocular lens system. The objective lens system comprises, from the object side, first, second, and third lens groups preferably comprising a single negative lens, a single positive lens, and a single negative lens, respectively. Two of the first, second, and third lens groups are axially movable for adjusting the magnification of the viewfinder. The objective lens system preferably includes a fourth lens group preferably comprising a single positive lens. The ocular lens system preferably comprises at least a positive lens and a reflector array for producing an erect image. Several groups of embodiments satisfy respective conditional expressions.

Abstract: A finder optical system is provided which is made up of an object lens system and an eyepiece system wherein the object lens system comprises, arranged from the object side:a first lens group, which has a negative lens L.sub.1,a second lens group, which has a positive lens L.sub.2, anda third lens group, which has a negative lens L.sub.3, and has an overall positive refractive power, and whereinthe eyepiece system is used for observing an image formed via the object lens system,the positive lens L.sub.2 of the second lens group in the object lens system has a bi-aspherical surface, andthe magnification of the finder optical system is changed by moving at least the second lens group in the object lens system along the optical axis.

Abstract: An optical system has a focal point detection device which is suitable for telephotography and is applicable to lenses having different image screen sizes. The optical system includes a photograph section which forms an image of an object, a driving device which moves either the entire photograph section or a part thereof in an optical axis direction, a plurality of re-imaging optical systems which forms re-images of the image of the object by light beams passing through different portions of a pupil of the photograph section, a plurality of imaging devices disposed in the vicinity of image planes of the re-imaging optical systems, and a controller which controls the driving device based on electric signals from the imaging devices so that the image of the object is formed on a mechanical image plane of the photograph section.

Abstract: Apparatus and methods are disclosed for re-imaging a primary image produced by a prime lens to form a positively demagnified secondary image at a secondary image plane, wherein the secondary image is smaller than, but has the same field angle as, the primary image. The apparatus comprises a field lens group and an optical relay. The optical relay can comprise a first lens group having negative refractive power, a second lens group having positive refracting power, and an erecting lens group interposed coaxially between the first and second lens groups. The apparatus also can comprise a beam-splitter imagewise to the optical relay to form multiple secondary images. The apparatus and methods have especial utility for adapting prime lens, designed for use on older, larger TV cameras, for use on newer, smaller TV cameras without sacrificing field angle.