Abstract: A viewfinder optical system includes, in order from an object side to an observation side, an objective optical system for forming a real image, a first optical member, the first optical member having a reflective surface by which to change a direction in which a light beam from the objective optical system advances, a second optical member, the real image being converted into an erecting image through the first optical member and the second optical member, and an eyepiece optical system for observing the erecting image, wherein the real image is formed on or near an exit surface of the first optical member, and the exit surface of the first optical member is a curved surface convex toward the observation side.

Abstract: A camera is capable of both silver-halide shooting, through which object images are recorded on silver-halide film, and video shooting, although its distance measurement device is placed substantially in the same way and its mirror box has substantially the same size as in ordinary single-lens reflex cameras. In this camera, a pellicle mirror splits the light flux having passed through a taking lens into a first light flux and a second light flux, and a rotatable mirror switches the subsequent path of the second light flux between the optical path for a third light flux and the optical path for a fourth light flux. The pellicle mirror, through its light flux splitting function, directs the first light flux to a silver-halide shooting system, and directs the second light flux to the rotatable mirror. The rotatable mirror, through its optical path switching function, either directs the third light flux to an optical viewfinder system, or directs the fourth light flux to a video shooting system.

Abstract: In a viewfinder optical system in a thin-type camera, the following are provided: first to fourth lenses for effecting image-forming operation; a first reflecting mirror for bending a principal optical axis 90 degrees in a heightwise direction of a camera; a second reflecting mirror for bending thin bent optical axis 90 degrees in a widthwise direction of the camera; a third reflecting mirror for bending this bent optical axis 90 degrees in an opposite direction to the heightwise direction of the camera; and a fourth reflecting mirror for bending this bent optical axis 90 degrees in a direction parallel with the principal optical axis. Despite the fact that the camera is made thin, its optical path length can be made long, and it is possible to form a viewfinder optical system having a high magnification of the viewfinder or a viewfinder optical system having a zooming structure.

Abstract: A real-image variable magnification finder includes an objective optical system of positive power, a condenser lens located at an image forming surface of the objective optical system, an eyepiece optical system of positive power, and an image erection optical system. The objective optical system of positive power includes a first positive lens group, a second negative lens group, a third positive lens group, and a fourth negative lens group. Upon change of magnification from the low magnification extremity to the high magnification extremity, the second lens group is moved to monotonically increase the distance between the second lens group and the first lens group; and the third lens group is moved to monotonically increase the distance between the third lens group and the fourth lens group while the first and fourth lens groups are kept immovable. The finder satisfies the condition defined by (1) 1.2<m.sub.4 <2, wherein m.sub.4 represents the lateral magnification of the fourth lens group.

Abstract: A secondary image formation type view finder comprising an objective optical system, a first mirror for folding an optical axis, a relay lens system and a second mirror for folding the optical axis, wherein an optical axis of the relay lens system is disposed so as to be included in a plane nearly perpendicular to an optical axis of the objective optical system, and the first mirror and the second mirror and disposed nearly in parallel with each other, thereby reducing a space to be occupied by the view finder.

Abstract: A real image finder system is disclosed. The finder system includes a common objective optical system for forming a real image of an object. A first erecting optical system for erecting an object image formed by the objective optical system, a first eyepiece optical system for observing an image erected by the first erecting optical system, a branch plane which is constructed as one plane of a plurality of reflection surfaces included in the first erecting optical system, and guides a luminous flux from the objective optical system to proceed along a first optical path and/or along a second optical path different from the first optical path, a second erecting optical system which is arranged on the second optical path and erects an object image formed by the objective optical system, and a second eyepiece optical system for observing an image erected by the second erecting optical system.

Abstract: A viewfinding system for use with an optical system that creates a first object image includes an objective block which is sealed as a unit. The objective block includes a focusing screen for forming the first object image and relay optics for transmitting the first object image. A zoom block includes a zoom optical system for providing a modification of the magnification of the first object image to provide a second object image. An eyepiece block receives the second object image and includes a reflecting member and an eyepiece through which the second object image is observed. The eyepiece block is sealed and the second object image is realized within the sealed eyepiece block.

Abstract: In a camera equipped with a zoom lens for forming an image of an object onto a film surface, the camera is equipped with a front lens group composed of a first lens group, adjustable aperture blades, a second lens group, and a second lens group-holding member; a back lens group provided; and an actuator to drive the adjustable aperture blade. The actuator is provided on the object-side from a space between the second lens group and the back lens group.

Abstract: A camera divides a light beam having passed through a taking lens unit into two light beams. One light beam forms an image on a silver salt film. Another light beam forms an image on a CCD. A light path for said another light beam is provided with an aperture diaphragm. The taking lens unit has an aperture diaphragm. Said two aperture diaphragms are correlatively controlled by a controller incorporated in the camera.

Abstract: A finder system for a single lens reflex camera includes a focusing screen having a split prism, a penta roof mirror and an eyepiece lens system. The penta roof mirror has a hollow housing made of plastic material in the shape of a pentagonal prism whose three surfaces are coated inside to reflect light. The eyepiece lens system includes two plastic lenses, each of which has a different dispersion.

Abstract: A viewfinder system adapted for a single-lens reflex camera includes an optical system which guides light from an object to a viewer, a display part which displays information in a visual field of the optical system, a light combining member which is disposed in an optical path of the optical system and combines the light from the object with the information displayed by the display part, the light combining member having spectral transmission characteristics which differ with angles of incidence of light, and a correction member for keeping a spectral transmission characteristic of the entirety of the optical system substantially constant irrespectively of the angles of incidence of light on the light combining member.

Abstract: An optical system comprising a photographing optical system, a light splitting element to split a light incident from an object, and a finder optical system to which the light split by the light splitting element is directed. A surface of the light splitting element is constituted as a ghost prevention surface that prevents light incident on the finder optical system from the eye side from being reflected, thereby preventing the ghost light (i.e., the light which affects the object image) from being incident on an image pickup surface. Alternatively, a wall surface of a casing of the optical system is employed as a ghost prevention surface.

Abstract: A finder optical system includes a photographing lens, an eyepiece having an optical axis substantially collinear with an optical axis of the photographing lens, and a relay optical system, including a relay lens system, disposed between the photographing lens and the eyepiece for optically connecting a primary focal plane of the photographing lens to a secondary focal plane disposed to be observed through the eyepiece. The relay lens system has an optical axis that is parallel with the optical axes of the photographing lens and the eyepiece, and the relay optical system includes a first pair of reflecting mirrors that relay the optical axis of the photographing lens to the optical axis of the relay lens system, and a second pair of reflecting mirrors that relay the optical axis of the relay lens system to the optical axis of the eyepiece.

Abstract: A viewfinder has an objective optical system and an eyepiece optical system. The viewfinder includes a supporting member which supports at least a part of either the objective optical system or the eyepiece optical system. The viewfinder further includes a hollow member provided separately from the supporting member. The hollow member is positioned in an optical path of the viewfinder such that a focal plane of the objective optical system is located in the hollow member. The viewfinder further includes a first transparent member secured to one end of the hollow member so as to face toward the objective optical system, and a second transparent member secured to another end of the hollow member so as to face toward the eyepiece optical system. An enclosed space in which the focal plane is located is formed by the first transparent member, the second transparent member and the hollow member.

Abstract: A camera that has the ability to direct the object light simultaneously to the imaging position and a first light receiving device and a second light receiving device that are arranged in places other than the imaging position (for example, an optical focus detection system and a monitor device of the object image) is disclosed. A first light dividing device is positioned in the light optical path of the light that is transmitted through the optical image forming system and reflects a portion of the light received and transmits another portion. A second light dividing device reflects a portion of the light that is reflected at the first light dividing device and transmits another portion. The light that is transmitted through the first light dividing device is directed to a primary imaging position. One of either the reflected light or the transmitted light of the second light dividing device is directed to the optical focus detection system, while the other one is directed to the monitor device.

Abstract: A real image finder system of a camera has an objective lens, an eyepiece lens and deflecting system. The deflecting system includes an erecting system positioned between the objective lens and the eyepiece lens. The finder system also includes an LCD panel that is located on an image plane of the objective lens with the LCD panel displaying information which is viewed through the eyepiece lens. A first polarizer is positioned between the objective lens and the LCD panel while a second polarizer is positioned between the LCD panel and the eyepiece lens. The first and second polarizers are arranged such that their transmission axes are perpendicular to each other. Further at least one optical component of the deflecting system is located between the first polarizer and the second polarizer.

Abstract: A prism 11 installed over focal plates 9 and 10 of a reflex-type stereo camera 1 is a composite prism forming two right and left inversion prisms as a unitary structure. The inner one-half pictures of the right and left inverted pictures on the focal plates 9 and 10 are inverted right side left through the prism 11, so that an erect image of the outer one-half picture in the photographing range of the left lens 5 is projected onto the left side of the central projection plane of the prism 11 and an erect image of the outer one-half picture in the photographing range of the right lens 4 is projected onto the right side thereby to synthesize a picture. Thus, the right and left images can be simultaneously seen through one finder, making it easy to view the image and to operate the camera.

Abstract: A seal apparatus for a finder having a liquid crystal display is provided with a liquid crystal body and a pair of polarizing plates. One of the polarizing plates is secured to an entrance opening or emission opening of a finder body to close the finder body.

Abstract: A sliding binocular body has two optical assemblies which slide on an intermediate plate to adjust for intraocular distance and which slide closed. Two shells are joined to form one assembly. Front and back contour plates cover the assembly. A field and eye lens holder slides into the box through the back plate. An eye piece is attached to the lens holder. Inward horizontal surfaces have inward extending rails, which engage outward facing grooves on the intermediate plate. The two shells are secured together and joined to the intermediate plate before mirrors are slid and clamped into place. The objective lenses are placed in position, and the contour plates are sealed in place. The eye lens and field lens are inserted in the holders before the holders are inserted in the assemblies. The assemblies hold and clamp mirrors against fixed reference surfaces. Objective lens holders formed in the assemblies permit vertical or horizontal adjustment of an objective lens before its fixing.

Abstract: A viewfinder device is arranged to have a pair of light deflecting members disposed in front and in rear of an objective lens, to drive the front light deflecting member to guide light of a left side area of a field of view and light of a right side area of the field of view alternately to the objective lens, and to drive the rear light deflecting member to guide light fluxes thus obtained from the objective lens alternately to the eye of a person taking a sight of the field of view. This arrangement enables the viewfinder device to make a wide range of field sightable and yet permits a reduction in size of the objective lens.

Abstract: A viewfinder device includes a first prism unit and a second prism unit. The first prism unit includes an incident/reflecting surface 1-1 for receiving and allowing light from the objective lens to enter the first prism unit, a surface 1-2 for reflecting the light entering from the surface 1-1, and a surface 1-3 for reflecting the light reflected by the surface 1-2. The second prism unit includes an incident/reflecting surface 2-1 for receiving and allowing the light reflected by the surface 1-3 to enter the second prism, a surface 2-2 for reflecting the light entering the surface 2-1, and a surface 2-3 for reflecting the light reflected by the surface 2-2. The surface 2-1 reflects the light reflected by the surface 2-3, and the objective lens forms an image between the first prism unit and the second prism unit.

Abstract: An indicator within a finder of a single lens reflex camera is provided with a simple construction. The indicator may include a mirror for reflecting light of an object transmitted through a photographing lens to form an object image onto a focusing plate, an finder optical system for viewing an image of the object formed on the focusing plate, a hollow-type pentagonal mirror, and a photographing information projector for projecting a plurality of light rays onto the focusing plate to form a photographing information image. The hollow type pentagonal mirror may include a pair of roof reflecting surfaces and a third reflecting surface for reflecting light, reflected by the pair of roof reflecting surfaces, toward an eyepiece optical system. The photographing information projector may be mounted in the vicinity of the pair of roof reflecting surfaces.

Abstract: An optical assembly with a folding mirror assembly is provided. The folding mirror assembly comprises first and second reflecting members having first through fourth reflecting surfaces and mounting means for mounting the reflecting members thereon. The first reflecting member has first and second reflecting surfaces in reflecting relation with each other, and the second reflecting member has third and fourth reflecting surfaces in reflecting relation with each other. The mounting means comprises a plate member having mounting pads, so that when first and second reflecting members are mounted to the mounting pads of the plate member, the third reflecting surface of the second reflecting member is in reflecting relation with the first reflecting surface of the first reflecting member.

Abstract: An Albada type inverted Galilean finder for a camera has an objective lens of negative power having a concave surface on a pupil side opposite an object side which is provided thereon with a half mirror coating and an eyepiece having a convex surface on the pupil side and a surface on the object side which is provided thereon with a framing marking defining an area for framing.

Abstract: A zoom viewfinder system for a single reflex camera comprises a relay optical system through which said first object image is formed as a second object image and plural reflecting members for reflecting light rays of said first object image, wherein the reflecting members except one reflecting member provided closest to a first object image is moved in order to adjust an angle of light rays of the first object image to the reflecting members. The zoom viewfinder system also comprises a holder for holding the reflecting members located parallel in the relay optical system in order to determine relative positions of the reflecting members precisely. The zoom viewfinder system further comprises holding members for holding plural parts of an optical system respectively, wherein each part is fixed to compose a viewfinder system, so that assembly and maintenance can be easy and the optical axis can be prevented from deviating.

Abstract: A viewfinder unit in a camera has a viewfinder objective optical system that contributes to formation of an object image.

Abstract: A finder optical system including an objective system, an image erecting system for erecting an object image formed by the objective system, and an eyepiece system for observing the object image. These systems are constructed of low-hygroscopic organic materials. Thus, the finder optical system can prevent transient variations of optical properties caused by hygroscopicity.

Abstract: A real image mode variable magnification finder optical system is provided with an objective lens having a positive refracting power and an eyepiece having a positive refracting power. The objective lens includes the first lens unit having a negative refracting power, the second lens unit having a positive refracting power which is movable for varying magnification, and the third lens unit having a positive refracting power which is movable for varying magnification. Moreover, the objective lens has the first reflecting surface for erecting an image on the entrance side of the region of a space provided on the object side of the second lens unit to move lenses when a change of magnification is made, and the second reflecting surface for erecting the image between the third lens unit and an intermediate imaging plane. Thus, the finder optical system brings about a reduction of thickness of a camera body, favorable correction for aberration, and cost reduction.

Abstract: A view finder includes a finder body which defines an optical path of the view finder and optical elements, including a roof mirror are provided along the optical path. The finder body has an opening for the roof mirror, so that the roof mirror is secured to the opening such that an outer portion of the roof mirror projects out of the finder body through the opening.

Abstract: A parallax correcting apparatus of a viewfinder that includes a roof mirror which is provided within the viewfinder. The roof mirror includes a pair of reflecting surfaces which are perpendicular to one another. The parallax correcting device includes a path which includes an optical axis of the viewfinder so that incident light is introduced to one of the reflecting surfaces. The parallax correcting apparatus is provided with an adjusting device to adjust the position of the roof mirror in a direction perpendicular to an optical axis such that the parallax effects are minimized or substantially eliminated.

Abstract: A finder apparatus for use with a lens-shutter type camera composing a zoom imaging optical system, a zoom finder optical system separate from said zoom imaging optical system, and an electronic flash device. The zoom finder optical system is made as a real-image zoom finder apparatus, with part of the associated optical elements being disposed behind the electronic flash device, and part of the optical path from the objective lens to the eyepiece being bent backward of the electronic flash device to pass through the optical element disposed behind the electronic flash device.

Abstract: A view finder optical system including a window of an eye piece portion comprising an eye cup having a contact surface, a shape of the contact surface being made so as to incline an axis of the lens with respect to an axis of the eye piece. The shape of the contact surface is curved corresponding to the lens's shape. The contact surface is made so as to conform to a lens of glasses.