Abstract: A zoom lens system for a compact camera, having a zoom ratio of approximately 2 or 3 and a smaller overall lens length at the telephoto end than the focal distance at the telephoto end, and which optically experiences only a small focus shift due to environmental changes such as temperature or humidity. The zoom lens system includes a positive lens group and a negative lens group. A positive plastic lens element is disposed in either the positive lens group or the negative lens group. The magnification of the system is adjusted by varying the distance between the positive and negative lens groups. The zoom lens system satisfies the following conditions:0.9<f.sub.t /f.sub.p <1.6 (1)0.6<m.sub.p '-m.sub.p <1.2 (2)2.9<m.sub.MAX <4.0 (3)where f.sub.t is the focal length of the overall system at the telephoto end, f.sub.p is the focal length of the positive plastic lens element, m.sub.

Abstract: A real image type of variable power view finder is disclosed which has an objective lens system, an image erecting optical system, and an eyepiece lens system, located in this order as viewed from an object to be photographed. The objective lens system includes negative and positive lens groups located in this order from the object side, so as to vary the distance therebetween, to change the magnification. The negative lens group of the objective lens system has at least two negative lenses.

Abstract: A zoom lens system having a zoom ratio of approximately 2 that is used with a compact camera. The system's overall lens length at the telephoto end is shorter than its focal length at the telephoto end, and it experiences small variations in aberrations during zooming. The present zoom lens system comprises, in order from the object side, a positive first lens group and a negative second lens group, which adjust the magnification by varying the distance therebetween. This lens system satisfies the following conditions:1.59<fw/f1<2.0 (1) and1.79<fw/f2<2.5 (2);where fw represent the focal length of the overall system at the wide-angle end; f1 represents the focal length of the first lens group and f2 represents the focal length of the second lens group (f2<0).

Abstract: A camera is provided having a view finder that includes a field frame varying mechanism for varying the ratio length between the longitudinal and lateral sides of a field of frame of the finder. An aperture varying mechanism is provided for varying the physical size of an aperture for exposure of a film in accordance with the ratio of field frame side lengths.

Abstract: A zoom lens system comprises, in order from the object side, a negative first lens group N, a diaphragm stop A, a positive second lens group P and a blocking element B for blocking deleterious rays of light, with the first and second lens groups N and P movable for zooming, and with the diaphragm stop A moving independently of the second lens group P during zooming. The lens system satisfies the conditions 2.5<Xs/fs<3.0, 0<.DELTA.XA/fs<X2/fs, and 0.ltoreq..DELTA.XB/fs<.DELTA.X2/fs, where Xs is the distance from the diaphragm stop to the image plane at the wide-angle end, fs is the focal length of the overall system at the wide-angle end, .DELTA.XA is the range of movement of the diaphragm stop, and .DELTA.XB is the range of movement of the second lens group.

Abstract: An albada finder comprising an objective lens group, which includes two negative lenses, and an eyepiece lens group, which includes two positive lenses, arranged in this order from the object side. A view frame is formed on the object side surface of the eyepiece lens group, and a half mirror is formed on the eye point side surface of the objective lens group. The finder satisfies the following condition:LD/lf.gtoreq.2 (1)wherein,LD is the lens full length (distance from the 1st surface to the 8th surface), andLf is the eye relief (distance from the 8th surface to an eye point).

Abstract: In an ocular lens system for use with a penta-mirror, an ocular lens includes a positive meniscus lens whose concave surface is directed to the pupil side and whose convex surface is directed to the object. The concave and convex surfaces of the positive meniscus lens are aspherical. The two surface are shifted to the pupil side from reference spherical surfaces defined by paraxial radii of curvature.

Abstract: A real-image variable magnification finder is capable of blocking deleterious rays of light without increasing the lens diameter or the size of the erecting prism even of the view angle is large. The improved finder includes, in order from the object side, objective lens system II, condenser lens III with which the image of the object formed by the objective lens system II is directed to eyepiece lens system V, erecting prism system IV for inverting the image of the object, and eyepiece lens system V, and the objective lens system II comprises at least two zooming groups IIA and IIB that will move along the optical axis and light shielding means A that is provided between the zooming groups for blocking deleterious rays of light.

Abstract: A zoom lens system for a compact camera, having a zoom ratio of approximately 2 or 3 and a smaller overall lens length at the telephoto end than the focal distance at the telephoto end, and which optically experiences only a small focus shift due to environmental changes such as temperature or humidity. The zoom lens system includes a positive lens group and a negative lens group. A positive plastic lens element is disposed in either the positive lens group or the negative lens group. The magnification of the system is adjusted by varying the distance between the positive and negative lens groups. The zoom lens system satisfies the following conditions:0.9<f.sub.t /f.sub.p <1.6 (1)0.6<m.sub.p '-m.sub.p <1.2 (2)2.9<m.sub.MAX <4.0 (3)where f.sub.t is the focal length of the overall system at the telephoto end, f.sub.p is the focal length of the positive plastic lens element, m.sub.

Abstract: An attachment lens system for close-up photography in use with a master lens system in such a fashion that the attachment lens system is attached to the front of the master lens system, comprising a first lens as a positive component, a second lens whose face on the object side is convex, the second lens serving as a positive component, a third lens whose face on the master lens side is concave, the third lens serving as a negative component, and the first to third lenses being arranged in this order from the object to the master lens system, and the specific conditions on the working distance, a negative power of the lens system of the attachment lens system on the master lens system side, and the thicknesses of the specific lenses contained in the attachment lens system being satisfied.

Abstract: A strobe unit in which a reflecting mirror is located behind a light source. The strobe unit includes an imaginary semielliptical reflecting mirror having a major axis located on an axis of illumination that passes through the center of the light source. Imaginary quarter-elliptical reflecting mirrors are formed by splitting the imaginary semi-elliptical reflecting mirror along the major axis into two mirror elements which are spaced a predetermined distance from one another in a direction perpendicular to the major axis. The reflecting mirror is defined by modified quarter-elliptical reflecting mirrors which are symmetrical in shape with respect to the axis of illumination and have a continuous smooth reflecting surface that extends between open ends of the imaginary quarter-elliptical reflecting mirrors, and ends which are adjacent to the light source and located between the imaginary semi-elliptical reflecting mirror and quarter-elliptical reflecting mirrors.