Abstract: An inverse Galilean view finder has an object lens and an eyepiece lens. The front of the object lens is flat surface. First micro corner cube prisms are arranged in a frame of visual field around the external periphery of the flat surface. Second micro corner cube prisms are arranged in a frame on the rear surface of the eyepiece lens. Light from an object is reflected toward the object lens by the second micro corner cube prisms. Reflective light from the second micro corner cube prisms is reflected by the first micro corner cube prisms, and returns to the eyepiece lens. The reflective light of the first micro corner cube prisms brights and it is observed within a finder as a finder field frame indicating a range of photography.

Abstract: Disclosed is a finder optical system that is provided with a relay optical system that forms a second image by erecting an inverted first image formed on a first image plane through a taking leas of a camera, and a magnifying optical system through which the second image is observed under magnification. The relay optical system includes a condenser lens, a reflecting prism and a relay lens arranged in the order from the first image plane toward an eyepoint. The following conditions (1) and (2) are satisfied; (1) 0.25<|mr|<0.35 (2) 0.75<f2/f3<0.85 where, mr is magnification of the relay optical system, f2 is a focal length of the relay lens, and f3 is a focal length of the magnifying optical system.

Abstract: Disclosed is a prism having a light incident surface, a light emerging surface, and at least one light reflection surface. The light incident on the light incident surface is reflected, inside the prism, by the light reflection surface, and emerged from the light emerging surface. At least one light reflection surface has a reflecting surface which does not satisfy a total reflection condition. A reflection area is formed on the at-least-one light reflection surface by applying light reflecting material. The reflection-area corresponds to a portion on which a normal light is incident. Further, a portion of the-at least-one reflection surface other than the reflection area is formed to be a low-reflection area-which has a lower reflectance index than the reflection area.

Abstract: A viewfinder optical system of a single-lens reflex camera has a photographic optical system and an image plane positioned on an optical axis of the photographic optical system. The system includes a first optical member positioned between the photographic optical system and the image plane, the first optical member bending the optical axis of the photographic optical system to define a viewfinder optical axis of the viewfinder optical system. A second optical member bends the viewfinder optical axis at least once to make the viewfinder optical axis that extends parallel to the optical axis of the photographic optical system. A third optical member, having substantially no optical power, is positioned on the viewfinder optical axis extending parallel to the optical axis of the photographic optical system. The third optical member is made of a transparent material having a refractive index higher than the refractive index of air.

Abstract: A view finder device has a Poro prism and a first optical system facing an emergent plane of the Poro prism. The first optical system is positioned beside the Poro prism and opposite to a recording medium passage through which an electro-developing recording medium is moved. A relay optical system is provided behind the recording medium passage, so that the eye point of the view finder is separated from the first optical system. A second optical system is provided behind the relay optical system, so that the image formed by the relay optical system is observed. Since the electro-developing recording medium can be moved between the first optical system and the relay optical system, the finder optical system can be disposed at a lower position.

Abstract: A single-lens reflex view finder wherein a partial amount of a light bundle transmitting through an imaging optical system which picks up an image of an object is split by optical path splitting means, one of split optical paths is used as a view finder optical path end focus confirming means is disposed only on a central portion of a refracting surface which is disposed at a location of an optional image formed in the view finder optical path.

Abstract: In a real-image finder, an objective optical system forms a real image and a reflecting member has a surface that reflects light from the objective optical system. A transmissive prism that transmits light from the reflecting member has an incident surface on which a light beam from the reflecting member is nearly perpendicularly incident and an emergent surface at an angle to the incident surface. The light from the transmissive prism is incident on an incident surface of a reflecting prism placed close to the emergent surface of the transmissive prism. A reflecting surface of the reflecting prism reflects light from the reflecting surface so that the light reflected from the reflecting surface is totally reflected by the reflecting prism incident surface. An eyepiece optical system guides the light from the reflecting prism to an observer.

Abstract: In the present invention, flash light is illuminated through a finder optical system and thereby the user can be notified of the moment of release operation. The camera size can be reduced by the following layout of the finder unit and the flash unit. This camera has a finder unit having a finder optical system (object lens group, mirror, prism and finder eyepiece window) and a flash unit including, for example, a midget bulb-type flash light illumination unit (discharge tube) and a reflector, which comprise the optical system for flash light illumination. A movable mirror is mounted and properly controlled so that part of the light path of the finder optical system (object lens group) also serves selectively as part of the light path of the optical system (object lens group) for flash light illumination. The above flash light illumination unit is installed behind the mirror on the extended optical axis of the object lenses.

Abstract: A real-image finder optical system including a positive objective optical system in which an image of an object, being upside down and reversed from left to right, is formed; an erecting optical system, having a plurality of reflection surfaces, in which the image formed by the objective optical system is erected to the same orientation as the object; and an eyepiece optical system through which the image erected by the erecting optical system is viewed. A shape of a finder field of view is a rectangle having major sides along the transverse direction in the finder field of view. Along the optical path on the side of the object with respect to the image formed by the objective optical system, at least three reflection surfaces of the erecting optical system are provided, and further, the most object-side reflection surface is positioned so that the optical axis is deflected in a direction along the major side of the rectangular finder field of view.

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: At minimum, a member near an image plane that is observed through an eyepiece is made of antistatic resin obtained by giving the resin itself ion conductivity so that its antistatic effect can be of long duration.

Abstract: A real image mode finder includes an objective optical system with a positive refracting power, an image erecting optical system with a roof reflecting section, a first planar reflecting section, and a second planar reflecting section, and an eyepiece optical system with a positive refracting power. The image erecting optical system is constructed so that the optical axis does not cross in this optical system and a ray of light from the objective optical system is introduced into the roof reflecting section, the first planar reflecting section, and the second planar reflecting section in this order. The real image mode finder also satisfies the following conditions: 49°<&ggr;<62.5° 20°<&agr;<30° where &ggr; is an angle of incidence of an axial ray of light on the second planar reflecting section and &agr; is an angle of incidence of the axial ray of light on the roof ridgeline of the roof reflecting section.

Abstract: An eyepiece optical system, which is used in a single lens reflex camera having a penta mirror, includes a negative first single lens element, a positive second single lens element, and a negative third single lens element, in this order from the penta mirror; wherein the second single lens element is a diopter adjusting lens element which is adjustable along the optical axis; and the following conditions are satisfied: −2<f1/fe<0  (1) 0.2<f2/fe<0.5  (2) −10<f3/fe<−1  (3) wherein f1 designates the focal length of the first single lens elements; f2 designates the focal length of the second single lens element; f3 designates the focal length of the third single lens element; and fe designates the focal length of the entire eyepiece optical system when the diopter is −1.0.

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: It is an object of the present invention to provide a finder prism capable of forming some in-finder information such as an automatic focus target mark and a short distance correction mark by virtue of extremely narrow lines. In detail, the finder prism is provided between an objective lens and an ocular lens, and is adapted to transmit an object image to a camera user under a condition where an automatic focus target mark and an short distance correction mark are overlapped on a photographing object image. In particular, the prism is made of a resin, a shouldered portion is formed on one surface of the prism from which the object light is allowed to exit during a photographing process, thereby forming some in-finder information such as an automatic focus target mark and an short distance correction mark.

Abstract: A penta prism mask havimg having an antireflective coating film on its surface, the antireflective coating film being an electrodeposition coating film formed by electrophoretic deposition using an electrodeposition paint comprising a dispersion of a resin and fine particles.

Abstract: A viewfinder device that includes a screen on which an image is projected, and an eyepiece lens through which the image is viewed. An optical member passes light beams from the screen to the eyepiece lens through an information display member, and a diffraction optical element diffracts light beams in the direction of the eyepiece lens so that diffracted light beams from the information display member are superposed over the viewed image.

Abstract: A viewfinder optical system directs a luminous flux emanating from an image plane to a pupil. The viewfinder optical system has an eyepiece optical system. The eyepiece optical system enlarges an image in order to be viewed by the pupil. The eyepiece optical system has a first lens unit, a second lens unit and a third lens unit. The first lens unit has at least one surface having a positive optical power. The second lens unit has at least one surface having a negative optical power. The third lens unit has a reflecting surface having a positive optical power.

Abstract: A finder for single-lens reflex type digital cameras includes a reflecting plane for splitting a light beam from an imaging optical system of a camera into two beams directed toward an image sensor and a finder system, a prism system for erecting an image, and an ocular optical system. The prism system has an entrance surface, a reflecting surface consisting of one plane, a reflecting surface of roof shape, and an exit surface. An optical path between the entrance surface and the reflecting surface consisting of one plane is practically perpendicular to an optical path between the reflecting surface of roof shape and the exit surface in the prism block.

Abstract: A real-image type viewfinder comprises a viewfinder optical system including a positive objective lens system for obtaining an inverted finder-image, an erecting optical system for converting the inverted finder-image into an erected finder-image, and an ocular lens system for viewing the erected finder-image through the erecting optical system. A half mirror is provided at a suitable location along a viewfinder optical axis, defined by the viewfinder optical system. A photometry optical system is provided along an extension of an incident optical axis, defined by a principal ray of light rays being incident on the half mirror along an optical axis of the objective lens system. An optical information-pattern-forming system is provided along an extension of a reflective optical axis, defined by a principal ray of light rays reflected by the half mirror toward the ocular lens system.

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 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 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 zoom lens system that is free from parallax, is compact, and offers excellent optical performance has, from the object side, a positive first lens unit, a negative second lens unit, a positive third lens unit, and a negative fourth lens unit. The zoom lens system has a half-prism between the second lens unit and the third lens unit so that a light beam having passed through the second lens unit is split by reflection.

Abstract: A variable length telescoping viewfinder for cameras that provides a variably adjustable eye viewing distance relative to the camera without changing the focus or magnification of the scene being photographed throughout the telescoping movement of the viewfinder. The light rays of the real image supplied to the viewfinder directly or indirectly from the camera are passed through a field lens, Pechan prism, relay lens system forming collimated light rays from the fixed front module to the movable rear module wherein lens elements form an intermediate image that is viewed through an eyepiece lens group. The front module is weakly powered and of a substantial effective optical length because of the inclusion of the Pechan prism. The image forming lens group of the rear module is weakly powered whereby relative telescopic movement between the front and rear modules does not adversely affect the location, focus or magnification of the intermediate image throughout the range of movement.

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 prism is provided having a surface on which light is made incident, surfaces at which light is reflected and a surface from which light is emitted. The prism includes an uneven surface portion provided on at least one of the incident, reflecting or emitting surfaces and located outside a light transmission area through which effective light of an associated optical system, in which the prism is to be incorporated, can be transmitted. The disclosure is also directed to a real image type view finder having such a prism.

Abstract: An intra-viewfinder display device includes an optical system having a light splitting surface and arranged to guide light coming from an object to a viewer, and a display element for displaying information by using light of a predetermined wavelength. The information displayed by the display element is transmitted to the viewer by utilizing the light splitting surface. The light splitting surface has respective different spectral characteristics with respect to light of a wavelength band including the predetermined wavelength and light of wavelengths not included in the wavelength band.

Abstract: A real image viewfinder of an optical device includes an eye piece through which an optical axis may be viewed with respect to a target frame. The target frame may be used for centering an optical image on an image forming plane and also for autofocus of the optical device. The real image viewfinder includes a first prism for redefining an optical axis within the optical device. The first prism has a pair of reflective planes joined about a first ridge line. The first ridge line generally includes a number of manufacturing flaws which are noticeable by the photographer. Thus, viewfinder components are shifted by a predetermined amount to present the first ridge line in an area of the viewfinder which is different from the target frame as viewed through the eye piece. Likewise, the real image viewfinder includes a second prism having a second ridge line which is also shifted away from the target frame as viewed through the eye piece.

Abstract: A camera has a finder optical system and a range measuring optical system which are provided independent of a photographing optical system. The finder optical system includes an objective system having a positive refracting power, an image inverting optical member having a plurality of reflecting surfaces for erecting an image formed by the objective system, and an eyepiece system having a positive refracting power. At least one of the reflecting surfaces constituting the image inverting optical member is disposed as a path splitting member In the optical path of the objective system so that one of optical paths split by the path splitting member is used for the finder optical system and the other is used for the range measuring optical system. A positive refracting power is provided, as a whole, between the path splitting member and the imaging plane of the objective system, without any refracting power between the path splitting member and a range measuring element.

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 lighting type bright frame finder has as objective lens having a negative focal length; an eyepiece having a positive focal length; a frame; and a joining prism joined through a half mirror. An optical path from the frame to the eyepiece is formed by arranging the joining prism such that the half mirror is located between the objective lens and the eyepiece. The lighting type bright frame finder is constructed such that a visual field image is overlapped with a frame image formed by only the eyepiece so as to observe these images. The focal length f.sub.e of the eyepiece, a distance E from an eye pupil side lens face of the eyepiece to an eye pupil face, and a maximum emitting angle .theta. satisfy the following condition (1).f.sub.e /(E.multidot.tan.theta.)<7.5 (1)In this lighting type bright frame finder, the number of constructional lenses can be reduced and the finder can be made compact. Other lighting type bright frame finders are also shown.

Abstract: An eye direction detecting apparatus for a camera having a light transferring system for guiding a beam of parallel light rays to an eye of a photographer includes a light receiving system having a light receiving portion on which a first Purkinje image based on specular reflection of a cornea of the eye and reflecting light from a retina of the eye is formed, the light receiving portion generating a light receiving output. The apparatus further includes a processing circuit for detecting the eye direction of the eye based on the light receiving output of the light receiving portion. Further, according to the teachings of the present invention, including an optical member having certain identically inclined surfaces prevents refracted light from forming a ghost image within the light receiving system of an eye direction detecting apparatus.

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