Abstract: An iris acquisition method for an electronic device is provided. The electronic device includes an iris camera and a proximity sensor. The proximity sensor includes an infrared ray emitter and an infrared ray receiver. The iris acquisition method includes: emitting a proximity infrared ray for detecting a proximity state by the infrared ray emitter; receiving the proximity infrared ray reflected from an external object by the infrared ray receiver; and upon the reception of the reflected proximity infrared ray by the infrared ray receiver, changing a transmitting power of the infrared ray emitter, so that the iris camera acquires iris information of an user.

Abstract: Remote depth sensing techniques are described via relayed depth from diffusion. In one or more implementations, a remote depth sensing system is configured to sense depth as relayed from diffusion. The system includes an image capture system including an image sensor and an imaging lens configured to transmit light to the image sensor through an intermediate image plane that is disposed between the imaging lens and the image sensor, the intermediate plane having an optical diffuser disposed proximal thereto that is configured to diffuse the transmitted light. The system also includes a depth sensing module configured to receive one or more images from the image sensor and determine a distance to one or more objects in an object scene captured by the one or more images using a depth by diffusion technique that is based at least in part on an amount of blurring exhibited by respective said objects in the one or more images.

Abstract: An intermediate image is formed inside a first prism, and an image light, which is reflected on the order of a third surface, a first surface and a second surface, is transmitted through the first surface and reaches the eyes of the observer, therefore it is possible to make the entire optical system small and light in weight by making the first prism thin, and realize a high performance display device with a wide angle of view. Further, when an external light is passed through, for example, the first surface and the third surface and observed, a diopter scale is set to approximately zero, and thereby reducing the defocus or distortion of the external light when observed in a see-through manner. And, it is possible such that the shape of the first prism conforms to the face of the observer, the center is also close to the face.

Abstract: A finder optical system includes an erecting optical system, an eyepiece optical system, and a light metering optical system. An optical axis of the light metering optical system is non-parallel to an optical axis of the eyepiece optical system. The light metering optical system includes a first lens having positive refractive power and a second lens having negative refractive power in this order from a side of the erecting optical system to a side of an image sensor, and the second lens is a prism body reflecting a light flux incoming from an incident surface off an inner reflection surface and outputting the light flux from a light outputting surface.

Abstract: In a variable magnification viewfinder device, information displayed on a liquid crystal panel and a viewfinder image are combined with each other through a prism. When a variable power lens is inserted in a viewfinder optical path, viewfinder magnification is changed. Based on the change in the viewfinder magnification, brightness of a backlight unit is changed and luminance of the information displayed on the liquid crystal panel is changed. In a viewfinder field of view, the information and the viewfinder image are displayed at substantially the same brightness.

Abstract: A camera viewfinder viewer accessory mountable on a camera includes an elongated body portion having first and second ends and a longitudinal axis extending from the first end to the second end. A light-transmitting passageway extends through the body portion from the first end to the second end. A connector is disposed adjacent to the first end. The body portion second end includes an angled face disposed at a generally 45° angle relative to the longitudinal axis. An eyepiece is connected to the body portion second end adjacent the angled face. The eyepiece has a longitudinal axis generally disposed at an angle that is 45 degrees relative to the longitudinal axis of the body portion. A viewfinder image is directed from the camera viewfinder along the longitudinal axis of the body portion, the image is redirected along the longitudinal axis of the eyepiece, to be viewed through the eyepiece.

Abstract: The view finder includes an observation optical system for enlarged observation of information displayed on a display section. The observation optical system includes an optical path bending member for bending the optical path. The view finder is configured such that an angle formed between a principal ray of a maximum angle of view and the display section is in the range of 90±5 degrees.

Abstract: A digital single lens reflex (DSLR) camera is provided for displaying predetermined photographing information, including focus information, camera information, etc., on a display screen of a viewfinder. The DSLR camera includes: the viewfinder for observing an image of an object; a pentaprism outputting the image of the object to the viewfinder; and a display device disposed on a side of the pentaprism to display photographing information.

Abstract: An adjustment device including an enhanced underwater viewfinder having, in use, a substantially watertight body and including a plurality of prisms within the body, at least one of the prisms being moveable by element of a control mechanism operable from a position exterior of the body.

Abstract: The present invention provides a visible and infrared light image-taking optical system which can facilitate changing a wavelength of infrared light used to take an infrared video image with an infrared light camera and which can achieve an infrared video image not affected by infrared light of any wavelength other than a desired wavelength, by separating object light incident on an image-taking optical system into object light in a visible light region and object light in an infrared light region and taking an object image formed by each object light for each object light in each wavelength region decomposed by the color separation optical system.

Abstract: The invention provides a viewing optical system comprising: a screen on which an object image by a taking lens is formed, an image erection optical system for erecting the object image formed on the screen, and an eyepiece lens system of positive refracting power for guiding a light beam leaving the image erection optical system to the eyeball of a viewer, wherein: the image erection optical system comprises a plurality of reflecting surfaces, the eyepiece optical system comprises, in order from a screen side to an exit pupil side, a first lens element of negative refracting power, a second lens element convex on both the screen side and the exit pupil side, and a third lens element that is of negative refracting power and has a meniscus shape concave on the exit pupil side, and the third lens element satisfies the following condition (1): 0.13<DL3/fe<0.

Abstract: A relay finder optical system, of a single-lens reflex camera, includes a condenser lens group, a prism, and a relay lens group, in this order from a primary imaging plane. An image, which is formed on the primary imaging plane, and is upside down and inverted from left to right, is re-formed on a secondary imaging plane for viewing by a photographer. The relay lens group includes a positive front lens group, a negative intermediate lens group, and a positive rear lens group, in this order from the object.

Abstract: A reflector assembly for use with an electronic device includes a light guiding member forming a light-guiding passage having a light guide assembly in the form of a plurality of lens assembled therein, the light guiding member is assembled in an electronic device having a display window formed in the front surface and a camera module formed in the back surface. An end of the light guiding member aligns with the camera module, the other end of the light guiding member extends to the front surface of the electronic device, outside lights can enter into light-guiding passage and be reflected by the lenses and reach to the camera module.

Abstract: Described is a wide-angle slip-on viewfinder (1) on rangefinder cameras for analog and digital wide-angle recordings of different image recording formats with lenses of different focal lengths, comprising three lens groups (LG1, LG2, LG3), a frame/mask unit (10) and a partially transmissive prism cube (8) which is designed as a combination element, wherein, on the light entrance side (4) in the viewfinder beam path (9), a first lens group (LG1) has a negative refractive power and the second and third lens groups (LG2, LG3) have a positive refractive power, wherein the second lens group (LG2) is composed of a first lens (L3) arranged downstream of the first lens group (LG1) and a second lens (L4) arranged on the light exit side (7) and the partially transmissive prism cube (8) is arranged between the lenses (L3, L4) and the third lens group (LG3) is arranged in a mask imaging beam path (11) which is at right angles to the viewfinder beam path (9) between the frame/mask unit (10) and the partially transmissive

Abstract: An electronic imaging apparatus having a section for generating imaging data which indicates an imaging condition; an optical finder mechanism for introducing light from a subject to a finder; a data display device for displaying at least one of the subject's image and the imaging condition in the finder; and a switching device for switching between light incident/non-incident states for the optical finder mechanism. When imaging is not performed, the switching device makes the light incident on the optical finder mechanism. When imaging is performed and the image signal is not recorded, the switching device makes the light incident on the optical finder mechanism, and the subject's image and the image formed by the data display device are superimposed and displayed in the finder. When imaging is performed and the image signal is recorded, at least the image formed by the data display device is displayed by the switching device.

Abstract: A display screen device includes a display panel on which a first image is displayed, and an electroluminescent display which displays a second image and is positioned to extend substantially entirely over one surface of the display panel so that the first image and the second image can be selectively displayed and so that the first image and the second image can be displayed in a superimposed manner.

Abstract: An in-finder display apparatus comprises: a finder optical system adapted to view an object image formed by a taking lens on a focal plane plate by means of an eyepiece lens through a penta roof prism, a display cell located on a display member disposed near an imaging plane for the object image, and an illuminating optical system for illuminating the display cell. The display cell is illuminated by the illuminating optical system so that light reflected off the display cell together with the object image is viewable via the finder optical system. The illuminating optical system comprises: a light emitting means, and a light projecting lens for converging a light beam leaving the light emitting means. The illuminating optical system is positioned such that an illuminating light beam leaving the light emitting means in the illuminating optical system enters the display cell after transmitting through the light projecting lens.

Abstract: A digital photographing apparatus is provided including a lens unit, an imaging device, and a main mirror disposed between the lens unit and the imaging device, wherein the position of the main mirror can be changed so that the main mirror either reflects at least part of light which passed through the lens unit toward a first orientation or the main mirror is not positioned on a path of the light which passed through the lens unit such that the light can be incident to the imaging device. A prism unit, a viewfinder, and an image sensor for live view are also included in the apparatus. A method of controlling the digital photographing apparatus, and a storage medium having recorded thereon a computer program for executing the method are also provided.

Abstract: At least one exemplary embodiment is directed to a viewfinder optical system which includes a first mirror having a roof shape configured to reflect light from an object image formed by a photographic lens towards the object image, a second mirror configured to reflect light reflected from the first mirror towards an observation side, and an eyepiece lens configured to receive light reflected from the second mirror. The second mirror includes a rotationally asymmetrical surface. The eyepiece lens includes at least one rotationally asymmetrical surface. The eyepiece lens includes a plurality of lenses, among which a lens closest to the second mirror includes a rotationally asymmetrical surface.

Abstract: In a viewfinder for a single lens reflex camera, in which a focused image of an object formed on a ground glass by a photographing lens is transmitted to an ocular optical system through a pentagonal prism or a pentagonal mirror and an information image displayed on an indication surface of an indication block is transmitted to the pentagonal prism or pentagonal mirror, through an indication prism, so that the object image and the information image are indicated in the finder view field of the ocular optical system, the indication surface of the indicator is inclined with respect to a direction perpendicular to an incident surface of the image-erecting optical member toward the incident surface, and an angle between the indication surface of the indicator and the incident surface of the image-erecting optical member is smaller than 90°.

Abstract: The invention relates to a viewing optical system for viewing an object image formed on a focusing screen, and an imaging apparatus comprising the same. An image erection optical system comprises a prism having an internal reflective surface. An eyepiece optical system comprises, in order from a screen side to an exit pupil side, a first lens component having negative refracting power wherein its exit pupil-side surface has a paraxial-radius-of-curvature absolute value smaller than that of its screen-side surface, a second lens component in a double-convex shape and a third meniscus lens component in a meniscus shape concave on an exit pupil side. The total number of lens components included in the eyepiece optical system is 3, and the following conditions (1), (2) and (3) are satisfied. 1.55<ndp??(1) 0.35<fe/Dip<0.60??(2) 1.0<D3/(D1+D2)<1.

Abstract: The finder optical system has a reflex mirror, a focal plane plate, a prism, an eyepiece, and a dust-proofing multilayer. The reflex mirror is disposed on an optical path of a photographing optical system. The focal plane plate is disposed at a position on which an image is formed by a light which passes through the photographing optical system and which is reflected by the reflex mirror. The light-input surface of the prism races a light-output surface of the focal plane plate. The eyepiece faces a light-output surface of the prism. The dust-proofing multilayer, which is provided on a surface of the focal plane plate, has a water-repellent or water- and oil-repellent layer and an anti-static layer.

Abstract: A relay finder optical system, of a single-lens reflex camera, includes a condenser lens group, a prism, and a relay lens group, in this order from a primary imaging plane. An image, which is formed on the primary imaging plane, and is upside down and inverted from left to right, is re-formed on a secondary imaging plane for viewing by a photographer. The relay lens group includes a positive front lens group, a negative intermediate lens group, and a positive rear lens group, in this order from the object.

Abstract: A light-emitting unit for superimposement is provided. The light-emitting unit is applied to one of a pentagonal roof-mirror or a pentagonal Dach-prism of a viewfinder optical system of a camera. The unit comprises a light source, a light-emitting lens, and a second mirror. The light source emits superimposing light. The second mirror reflects light emitted from the light source and passed through the light-emitting lens toward a third reflection face of one of a pentagonal roof-mirror or a pentagonal Dach-prism. The light source, the light-emitting lens, and the second mirror are integrally assembled as a unit.

Abstract: An image-taking lens apparatus has an image sensor for converting an optical image of a subject into an electrical signal and an image-taking lens system for forming the optical image on the image sensor. The image-taking lens system includes a prism for bending the optical path, and the refractive index of the prism fulfills a prescribed conditional formula.

Abstract: An observation optical system of the present invention comprises an image erect optical system and an eyepiece optical system for observing an object image. The eyepiece optical system comprises a positive single lens having double convex surfaces and a negative meniscus lens having a concave surface directed toward eye point side, and the following condition is satisfied: 0<S<0.3 0.05<d1/f<0.15 where S=(r1?r2)/(r1+r2), r1 is a curvature radius of the object image side surface of the negative meniscus lens, r2 is a curvature radius of the eye point side surface of the negative meniscus lens, d1 is a distance of air space between the positive single lens and the negative meniscus lens, which represents a distance of air space when diopter of the observation optical system is adjusted to be ?0.8 (m?1) if the air space is changed, and f is a focal length of the eyepiece optical system.

Abstract: A finder optical system includes an eyepiece optical system with a positive refracting power. The eyepiece optical system includes an optical unit with a positive refracting power and a lens unit with a positive refracting power, In the eyepiece optical system, a refracting surface that is located most distant from an eyepoint of the eyepiece optical system has a positive refracting power and is configured as an aspherical surface with a negative refracting power on a periphery thereof.

Abstract: A thin viewfinder device includes, in order an object side to a viewing eye side, a first prism, and a second prism disposed separately from the first prim across an air gap. The first prism, the air gap and the second prism are arranged in such a manner that an object light flux obtained within a viewing field passes through the first prism, the air gap and the second prism so as to reach the viewing eye, while an object light flux obtained outside the viewing field is totally reflected by surfaces of the first prism so as to be prevented from reaching the viewing eye.

Abstract: A light-projecting device comprises a superimpose-plate, which is put on a focusing glass. A hollow pentagonal mirror has a roof reflecting plane, reflecting a light beam passing through the focusing glass and the superimpose-plate, a third reflecting plane, reflecting the light beam reflected on the roof reflecting plane, and an emergent opening through which the light beam reflected on the third reflecting plane passes. An illumination light beam output from a light source of a light-projecting optical system is reflected on a light-projecting prism, and radiated from the emergent opening to the third reflecting plane. The illumination light beam is reflected on the third reflecting plane and the roof reflecting plane, and is approximately perpendicularly radiated on the superimpose-plate.

Abstract: A real image mode finder optical system is constructed to be independent of a photographing optical system and includes, in order from the object side, an objective optical system with a positive refracting power, a field frame located in the proximity of the imaging position of the objective optical system, and an eyepiece optical system with a positive refracting power. The real image mode finder optical system has an image erecting means, and the focal length of the objective optical system can be made shorter than that of the eyepiece optical system. In this case, the real image mode finder optical system satisfies the following condition: 0.52<mh/fe<1 where mh is the maximum width of the field frame and fe is the focal length of the eyepiece optical system.

Abstract: An image-erecting viewing optical system includes a first prism having an incident surface and at least two reflection surfaces, a front lens group of an objective optical system, a second prism having an incident surface and at least two reflection surfaces, a rear lens group of the objective optical system, a field stop, and an eyepiece optical system, in this order from the object. One reflection surface of the first or second prism includes a roof-mirror surface. The following conditions are satisfied: sin(????)>1/n??(1) 6°<?<16°??(2) wherein ? designates an angle between the incident surface and the first reflection surface of the first prism; ? designates a real field-of-view ? (half amount); ?? designates an angle between a light ray of a real field-of-view ? (half amount) and the optical axis within the first prism; and n designates the refractive index of the first prism.

Abstract: The present invention relates to a high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. A prism member 10 has a first entrance surface 11, first to fourth reflecting surfaces 12 to 15, and a first exit surface 16. An optical path incident on the first reflecting surface 12 and an optical path reflected from the second reflecting surface 13 form intersecting optical paths. An optical path incident on the third reflecting surface 14 and an optical path reflected from the fourth reflecting surface 15 form intersecting optical paths. At least either one of the first reflecting surface 12 and the second reflecting surface 13 and at least either one of the third reflecting surface 14 and the fourth reflecting surface 15 have a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration.

Abstract: A camera is provided that includes a camera housing and a TFT panel, which permits verification of a formed image, located on the back of the camera housing. A strobe unit and an electronic viewfinder unit are located in the upper part of the camera housing. The electronic viewfinder unit has a unit body including: a TFT panel permitting viewing of an object image; an eyepiece opposed to the back of the camera housing and used to view the object image displayed on the TFT panel; and a prism serving as an optical path conversion member that bends by a predetermined angle light emitted from an object image displayed on the TFT panel so as to route the light to the eyepiece, and adjoining the TFT panel and the eyepiece.

Abstract: An optical and electronic viewer of a camera has a body having entrance and exit openings and entrance and exit tunnels extending inward from respective openings. The body has a cross tunnel connecting the entrance and exit tunnels. An eyepiece is mounted at the exit opening and defines and eyepiece axis. An objective lens is mounted at the entrance opening and defines an objective axis. An electronic imager is disposed within the body, in optical alignment with the objective lens. A microdisplay is mounted in the exit tunnel interior to the eyepiece. First and second reflectors are disposed in the cross tunnel. The reflectors are aligned and are each movable, within the cross tunnel, between an optical-viewing position and a non-viewing position. The first reflector is aligned with the objective axis and the second reflector is aligned with the eyepiece axis in optical-viewing position. The reflectors are spaced from the axes and each other in non-viewing position.

Abstract: A compact finder with excellent optical performance, and a camera including the finder are disclosed. The finder of the present invention includes an objective optical system, and an eyepiece optical system. The objective optical system includes, from an object side to an image side, a first lens unit having positive power, a second lens unit having negative power, a third lens unit having positive power, and a fourth lens unit having positive power. During zooming from a wide-angle end to a telephoto end, the second lens unit is moved toward the image side, the third lens unit is moved toward the object side, and the fourth lens unit is moved such that an air space between the fourth lens unit and the third lens unit is changed. The camera of the present invention includes a photo-taking optical system, and the finder of the present invention whose optical axis is different from an optical axis of the photo-taking optical system.

Abstract: A real-image variable-magnification viewfinder includes objective optical system having positive optical power, eyepiece optical system having positive optical power, and erecting optical system. The objective optical system has first lens unit having positive optical power, second lens unit having negative optical power, and third lens unit having positive optical power. As zooming is performed from wide-angle end to telephoto end, second and third lens units are moved so they come closer to each other. Following conditional formulae are fulfilled: −0.75<m2W<−0.3, −2<m2T<−1.05, −0.75<m3W<−0.3, −2<m3T<−1.05, l2>l3, where m2W and m2T represents lateral magnification of second lens unit at wide-angle end and at telephoto end, m3W and m3T represents lateral magnification of third lens unit at wide-angle end and at telephoto end, and L2 and L3 represent movement distance of second lens unit and of third lens unit over entire zoom range.

Abstract: A camera including a photographing optical system and a finder optical system, includes an objective optical system and an ocular optical system, the optical axes thereof being parallel with each other; a reflection surface which reflects a light bundle in the vertical direction of the camera; a reflection surface which reflects the light bundle in the horizontal direction of the camera toward an light-emitting optical axis of the ocular optical system; and a reflection surface located on the light-emitting optical axis to make a connecting optical axis coincident with the light-emitting optical axis of the ocular optical system. The connecting optical axis is inclined with respect to the horizontal direction of the camera so that the optical axes of the objective optical system and the ocular optical system are close to each other with respect to the vertical direction of the camera.

Abstract: A real image mode finder optical system is constructed to be independent of a photographing optical system and includes, in order from the object side, an objective optical system with a positive refracting power, a field frame located in the proximity of the imaging position of the objective optical system, and an eyepiece optical system with a positive refracting power. The real image mode finder optical system has an image erecting means, and the focal length of the objective optical system can be made shorter than that of the eyepiece optical system. In this case, the real image mode finder optical system satisfies the following condition: 0.52<mh/fe<1 where mh is the maximum width of the field frame and fe is the focal length of the eyepiece optical system.

Abstract: The invention relates to a viewing and an image pickup optical system for display devices, which can be used with high efficiency at a plurality of wavelengths and enables bright images to be viewed with satisfactory color reproducibility. The optical system comprises a first prism 3, a second prism 4 and a volume hologram element 6 disposed between them and cemented to them. The hologram element 6 comprises a first grating vector corresponding to at least a first wavelength and a second grating vector corresponding to a second wavelength shorter than the first wavelength.

Abstract: The invention relates to a view finder with improved structure for providing accurate posisioning and alignment of optical elements of its optical system. The view finder comprises an object lens system at least one lens of which is movable along an optical axis of the object lens system being guided by a first guide shaft and an eye-piece lens system at least one lens of which is movable along an optical axis of the eye-piece lens system being guided by a second guide shaft, wherein the first guide shaft and the second guide shaft are positioned in axial alignment. Preferably the first guide shaft and the second guide shaft are integrally formed and immovable optical elements such as fixed lens and prism of the optical system are also supported by the same guide shaft.

Abstract: A finder device is disclosed in which a finder optical system is provided with an auto-focus function separate from that of a photographic optical system so that the subject image can be observed sharply even when the finder optical system undergoes a change of state due to temperature and other causes. A semitransparent mirror is interposed between an objective lens system and an erecting optical system to branch out a focus detection system optical path from a finder system optical system. A focus detection device is arranged on the focus detection system optical path so that its focus detection plane is situated at the equivalent position to the focal plane of the finder. The state of focus is obtained from the subject image formed on the focus detection plane by using a phase difference detection system or the like. Driving means moves a focus lens system forward/backward along the optical axis so that the subject image focuses on the focus detection plane.

Abstract: The present invention concerns a camera incorporating a real-image finder, having a structure more compact than ever. The camera includes an objective optical system; an erect-image optical system, having a reflecting surface, to receive a light bundle passed through the objective optical system; and an ocular optical system to receive the light bundle reflected from the reflecting surface of the erect-image optical system. In the camera, a rear end of the reflecting surface is located at a backward position with respect to a film conveyance surface and outside the film conveyance surface, and, a front end of the reflecting surface is located at a forward position with respect to the film conveyance surface and inside the film conveyance surface.

Abstract: A viewing optical system for display apparatus allows observation of a bright displayed image favorably corrected for aberrations and is easy to assemble, resistant to impact such as vibration, lightweight and compact. An ocular optical member for leading an observation image formed by an observation image forming member to an exit pupil has a first prism member and a second prism member. The first prism member has a first entrance surface, a reflecting surface and a first exit surface disposed to face each other across a first prism medium. The second prism member has a second entrance surface and a second exit surface disposed to face each other across a second prism medium. The first and second prism members are cemented together with a holographic element interposed between the first exit surface and the second entrance surface. The reflecting surface has a positive power. The first exit surface and the second entrance surface are each formed from a plane or cylindrical surface.

Abstract: A camera including a liquid crystal display in which an image formed by a photographing lens system of the camera is indicated; an ocular viewing optical system which includes a half-mirror surface and an eyepiece lens system, the half-mirror surface reflecting the image of the liquid crystal display toward the eyepiece lens system, so that the reflected image can be viewed through the eyepiece lens system; and a direct viewing optical system for viewing the image of the liquid crystal display through the half-mirror surface.

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a single prism. When image-side three surfaces of the prism are defined as a surface A, a surface B and a surface C in order from the image plane side thereof, at least one of the surfaces B and C has a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration. The optical system leads light rays from an object to the image plane without forming an image in the prism and has a pupil in the prism. The surface A is a transmitting surface through which rays exit from the prism. The surfaces B and C are internally reflecting surfaces. Rays incident on the surface C and rays reflected from the surface B intersect each other in the prism.

Abstract: An adjustable viewfinder optical system for a shoulder-supported movie or video camera having interchangeable objective lenses. The system includes first and second lens groups aligned on an optical axis for receiving and relaying an image received from the objective lens of the camera to the viewer's eye. The first lens group is in a forwardly extending portion of the viewfinder that is pivotally joined to a rearwardly extending portion of the viewfinder containing the second lens group. The forwardly extending portion has a telescoping portion for varying the eye position of the viewer relative to the camera in the fore-and aft direction. The light is collimated between the first and second lens groups at the telescoping portion, whereby the image viewed in the viewfinder remains in focus and the same magnification throughout the telescoping adjustment movement.

Abstract: A real image type finder is provided with an imaging optical system, a focusing glass disposed at a focusing surface of the imaging optical system, an observing optical system for observing an image formed on the focusing glass, a case that accommodates the focusing glass and the observing optical system. The case is formed with an opening that allows only the focusing glass to be inserted in/withdrawn from the case therethrough. The finder is further provided with a covering means that removably covers the opening.

Abstract: A camera including a photographing optical system and a finder optical system, includes an objective optical system and an ocular optical system, the optical axes thereof being parallel with each other; a reflection surface which reflects a light bundle in the vertical direction of the camera; a reflection surface which reflects the light bundle in the horizontal direction of the camera toward an light-emitting optical axis of the ocular optical system; and a reflection surface located on the light-emitting optical axis to make a connecting optical axis coincident with the light-emitting optical axis of the ocular optical system. The connecting optical axis is inclined with respect to the horizontal direction of the camera so that the optical axes of the objective optical system and the ocular optical system are close to each other with respect to the vertical direction of the camera.

Abstract: A viewfinder for a camera with an adjustable diopter includes an objective lens and an eyepiece lens each having an optical axis extending parallel to a longitudinal axis of the camera. Light rays from the objective lens are reflected by a mirror and directed in one direction parallel to a transverse axis of the camera onto a focusing screen to form an object image. A first triangular prism receives light rays from the object image and reflects and directs the received light rays in opposite direction parallel to the transverse axis. A second triangular prism receives light rays from the first prism and reflects and directs the received light rays in the direction parallel to the longitudinal axis and toward the eyepiece lens. The first prism is supported and guided for linear displacement along the transverse axis, while the second prism is fixed to the body frame of the camera.

Abstract: An appartus, such as a binocular telescope, with an optical system which includes a long optical path. The binocular telescope includes a first objective lens, a second objective lens, a first prism, a second prism, and a group of eye piece lenses. A body of the second prism has an outer surface on which a film made of aluminum is deposited. A light which passes through the first objective lens is firstly reflected by an outer surface, or an exposed side, of the deposited film, and then reflected by an inner surface, or a side contacting the body of the second prism, of the film after the light passes through the second objective lens, the first prism and the second prism. The light reflected by the inner surface of the film is projected outside through the second prism and the eye piece lenses. The single deposited film serves as a pair of reflection elements within the optical system, so that the long optical path is secured therein.