JPH0325422A - Finder for camera - Google Patents

Abstract

PURPOSE:To prevent a finder size from being scaled up by allowing one means to simultaneously correct parallax and diopter. CONSTITUTION:When a photographing optical system is selected to be in a micro-photographing position, an objective lens 2 is moved in a direction perpendicular to the optical axis 1 of a finder optical system by a driving mechanism. Simultaneously, the lens 2 moves forward in the direction of the optical axis, and is located at a second position II. Since the objective lens 2 is located in the second position II, a luminous flux orienting a camera from any one point in the optical axis 1 of the photographing optical system converges closer to an object side than when the objective lens 2 is in a first position I, and the refracting direction of the luminous flux in that condition is altered, compared to when the lens 2 is in the first position I. Consequently, parallax and diopter can be corrected so that the luminous flux can form an image in the center of a prescribed image forming plane. Therefore, the configuration of the finder can be simplified to miniaturize the finder.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a camera finder having a photographic optical system and a finder optical system separately, and more specifically, the present invention relates to a camera finder having a photographic optical system and a finder optical system, and more specifically, the present invention is provided with means for correcting parallax and diopter deviation that occur in the finder optical system when performing macro photography. Regarding the finder.

[Prior art and its problems]

Conventionally, in cameras other than single-lens reflex cameras, the finder optical system is generally configured with an optical axis separate from that of the photographic optical system. Therefore, for example, light directed toward the camera from an arbitrary point on the optical axis of the photographic optical system forms an image on the leading axis of the photographic optical system, but forms an image at a position offset from the optical axis in the finder optical system. The amount of deviation in the imaging position, or parallax, is so small that it does not pose a problem when the distance between any one point and the imaging plane is extremely far, but it increases as the distance approaches, and the parallax The deviation from the center of the viewfinder field of view gradually increases. Particularly when performing macro photography, if the field of view remains the same as when taking normal photographs, the screen constructed by the finder will differ from the actual photograph. As one configuration for solving this problem, as shown in FIGS. 6A and 6B, a field frame 38 for macro photography is drawn in the viewfinder in addition to the field frame for normal photography. However, even in this case, since it is not possible to see all four corners of the field of view during macro photography, it is very difficult for the photographer to accurately grasp the photographic range. and,
For example, if the photographer is an inexperienced person in operating a camera, he or she may not even be aware that the shooting range must be aligned with the field of view frame drawn in the viewfinder during macro photography. . In addition, as another configuration for correcting parallax,
One example is a finder optical system with an optical element added. Regarding this, for example, Japanese Patent Application Laid-Open No. 62-2843
This technique is disclosed in Japanese Patent Application Laid-open No. 36, Japanese Patent Application Laid-Open No. 63-52114, and Japanese Utility Model Application No. 63-70539, etc., but all of these techniques place a prism on the objective lens side of the finder optical system. Parallax is corrected by utilizing the refraction of light by this prism. On the other hand, in the case of a single-lens, one-nof camera, the image is always focused on the image forming plate and then observed even if the shooting distance changes, so the subject can be seen even in the viewfinder. The image can always be seen in the same position. Therefore, since the distance between the photographer's eye and the image forming position does not change, it can be said that the degree of perspective, or diopter, at which the image is visible is always constant. However, in a camera as described above in which a photographing optical system and a finder optical system are provided separately, the viewfinder optical system is generally not changed, so the image forming position also changes as the photographing distance changes. In other words, the diopter changes and the image becomes difficult to see. and,
Particularly when the diopter changes greatly, such as when performing macro photography, in extreme cases you may not be able to see an in-focus image in the viewfinder. On the other hand, this means that when performing macro photography, it is possible to correct the diopter by changing the finder optical system, but even in that case, it is necessary for the photographer to see the appropriate image. There is still a need to correct parallax. Therefore, if a parallax correction means is provided separately from a means for changing the finder optical system to correct the diopter, there is a problem that the finder becomes larger due to the complicated structure. The present invention was devised to effectively solve such conventional technical problems. Therefore, its purpose is
In order to prevent the finder from becoming too large, the objective is to simultaneously perform parallax correction and diopter correction using one solution.

[Means to solve the problem]

The camera finder according to the present invention may be constructed as follows in order to achieve the above-mentioned object. That is, the finder of a camera is equipped with a photographing optical system capable of selecting a normal photographing position and a macro photographing position, and a finder optical system having an objective lens and an eyepiece, and the viewfinder is a camera that is equipped with a photographing optical system that can select a normal photographing position and a macro photographing position, and a finder optical system that has an objective lens and an eyepiece. At the time of selection, the objective lens is positioned at the first position on the optical axis in order to form an image on a predetermined image plane, while the lens of the photographing optical system is refracted to create parallax by refracting the optical path of the subject. At the same time, the luminous flux is corrected. H. In order to correct the diopter while avoiding convergence on a predetermined image forming plane, a lens drive mechanism is provided that positions the objective lens at a second position that is perpendicular to the optical axis and located in front of the optical axis with respect to the first position. We are prepared.

[Action/effect]

In the above configuration, when the photographing optical system selects the normal photographing position, the objective lens is positioned at the first position on the finder optical axis by the drive mechanism. Then, the image is formed into a predetermined image within the field of view of the finder. 1. Therefore, at this time, the photographer can clearly see the image in the finder. On the other hand, when the photographing optical system selects the macro photographing position, the objective lens is moved by the drive mechanism in a direction perpendicular to the optical axis of the finder optical system, and at the same time, also moved forward in the optical axis direction. located in position. By positioning the objective lens in the second position, for example, the light beam directed toward the camera from any point on the optical axis of the photographic optical system is converged closer to the subject than when the objective lens is in the first position. Since the refraction direction changes compared to the case at the first position, it is possible to correct parallax and diopter so that the light beam is focused on the center of the above-mentioned predetermined imaging plane. Therefore, with this finder, the appropriate photographing range can be clearly seen even in the macro photographing state. As explained above, according to the above configuration, parallax and diopter deviation can be corrected at the same time. Therefore, there is no need to provide these Urasa means separately,
The configuration of a finder that allows a clear view of an appropriate image corresponding to the photographing range can be simplified as much as possible, and further downsized.

【Example】

An embodiment of the present invention shown in FIGS. 1 to 5 will be described in detail below. First, the fine optical path according to this embodiment will be explained based on FIG. The figure shows the optical path of the finder optical system when it is installed above the photographic optical system. As shown in the figure, this optical system includes an objective lens 2, a first condenser lens 3, a relay optical system 6, a second condenser lens 9, and an eyepiece lO. Note that 4 and 7 indicate image formation planes, and one of them is provided with a field frame (not shown). When performing macro photography with a camera in which the finder optical system is configured separately from the photographic optical system, the light beam directed in direction A from the center of the photographic range to the camera is transmitted to the finder optical system with respect to its leading axis l. incident at a certain angle. At that time, if the objective lens 2 is located at the same position as during normal photography, that is, at the first position I, the incident light travels as shown by the broken line and is first formed as an inverted image at position 5. Then, it passes through the relay optical system 6 and forms an erect image at position 8. In this case, in addition to the occurrence of parallax depending on the angle of incidence, the subject is closer than normal photography, so the image is closer to the eye 11 than the imaging planes 4 and 7 where the image is normally seen clearly. Since the image is formed at a position shifted from the above, a shift in diopter occurs at the same time. On the other hand, the objective lens 2 is moved to a position (
In this embodiment, by positioning the photographic subject at the lower position), that is, the second position ■, it is possible to converge the above-mentioned light flux to a point on the optical axis 1 so that the subject image is formed on the regular imaging plane 4. It becomes possible. This is because the focal length of the objective lens 2 itself does not change, so by moving the objective lens 2 toward the subject by the amount of deviation in diopter, the deviation can be absorbed, and the objective lens 2 can be moved along the optical axis. This takes advantage of the property that by positioning the objective lens 2 at a position eccentric to l, the refraction direction of the light transmitted through the objective lens 2 changes from the refraction direction when the respective axes are aligned. Therefore, the image of the subject can be formed on the original image forming apparatuses 4 and 7 with the center of the viewfinder field of view and the center of the photographing range aligned. In this manner, by moving the objective lens 2 to an appropriate position, it is possible to simultaneously correct parallax and diopter deviation during macro photography. In this embodiment, the image is reversed in the vertical and horizontal directions using the relay optical system 6, but this is achieved by using a Boro prism or an equivalent optical system using a reflecting mirror instead of the relay optical system. Needless to say, it is also possible to use a so-called worn-out mirror. Next, a driving mechanism for the objective lens 2 will be explained using FIGS. 2 to 5. FIG. 2 is a sectional view of a main part showing the drive mechanism of the objective lens 2 in this embodiment, and FIG. 3 is a perspective view. In the figure, l2 is a cam cylinder that holds each lens that makes up the finder optical system. A gear 13 is formed on the circumference of the rear end of the cam 12, and a gal 15 connected to the motor 14 meshes with the gear 13. On the other hand, a spiral cam II41 is provided at the tip of the cam 1912.
6 is formed. A first cam follower 18 provided in an objective lens frame l7 that holds the objective lens 2 is engaged with the cam groove 16, and at the same time, the objective lens frame 17 is attached to the camera body within the cam frame 12. It is also slidably engaged with a diagonal guide 19 fixed thereto. If necessary to converge the light beam onto a predetermined image plane 4, a positive lens 2 may be installed behind the objective lens 2, as shown in the figure.
0 may be provided and this lens 20 may be moved in the optical axis direction. In this case, what is shown is a spiral cam groove 37 provided behind the cam groove 16 in the cam groove 12, and a second cam follower 22 provided in the lens holding frame 2l that holds the lens 20 in this cam groove 37. and engage the lens holding frame 2.
1 is simultaneously slidably engaged with a straight guide 23 fixed to the camera body behind the lens oblique guide 19. If the drive mechanism of the objective lens 2 is configured as described above, when transitioning from normal photography to macro photography, the cam l2 is rotated by the rotation of the motor l4, and the cam 116,
By the action of the cam follower l8 and the oblique guide l9, the objective lens 2 moves from the illustrated position forward in the direction of the optical sleeve and downward with respect to the optical axis. Then, by moving the positive lens 20 in the optical axis direction, an accurate subject image that coincides with the center of the photographing range is formed on the predetermined imaging plane 4. Therefore, according to this configuration, although the size is comparable to that of a finder equipped with only either a diopter correction means or a parallax correction means, it can simultaneously correct parallax and diopter deviation during macro photography. It becomes possible to make corrections. Note that the objective lens driving mechanism may have the configuration shown in FIGS. 4 and 5. FIG. 4 is an enlarged side view showing a drive mechanism according to a modified example, and FIG. 5 is a front view of a finder having this drive mechanism. As shown in FIG. 5, the objective lens 24 has a rectangular shape, and is therefore held in a rectangular objective lens holding frame 25. As shown in FIG. The objective lens holding frame 25 is connected to the lens frame 26 by the link levers 2 7, 3.
It is attached via 6. Specifically, the link lever 27 has its intermediate portion connected to the pin 2 provided on the lens barrel 26.
8, and one end is pivotally supported by a bin 29 provided on the holding frame 25 (in the case of the link lever 36, the bins 28 and 29 are ). On the other hand, a rotatable disk 3l is provided inside the body of the camera, and a pin 32 provided at a position on this disk 3l, a pin 30 provided at the other end of the link lever 27, etc. They are connected by a connecting lever 3"3. A motor 34 for rotating the disc 3l is connected to the disc 3l. Also, the objective lens 24 is moved when the driving force of the motor 34 is cut off. The spring 35 connected to the link lever 27 always urges the lens element 26 to ensure the i-th position I during normal photography.In this configuration, the motor is rotated and its driving force is When this is transmitted to the disk 3l, the objective lens 24 moves diagonally downward from that position toward the subject due to the action of the link mechanism, along with the holding frame 25. Therefore, it moves to the second position shown by the solid line in FIG. Therefore, it is possible to correct parallax and diopter deviation at the same time.In other words, even with this configuration, only either the diopter correction means or the parallax correction means is provided. Although it is about the same size as a conventional finder, it is possible to simultaneously correct parallax and diopter deviation during macro photography.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the general structure and optical path of a finder according to an embodiment of the present invention, FIG. 2 is a sectional view of main parts showing the drive mechanism of the objective lens 2, FIG. The figure is an enlarged side view showing a drive mechanism according to a modification, FIG. 5 is a front view of the finder, and FIGS. 6A and 6B are schematic diagrams showing a field frame provided in a conventional finder. l...Finder optical system optical axis, 2...Objective lens, 3,9...Condenser lens, 4,5,7.8...
...Imaging surface, 6...Relay optical system, 10...Eyepiece, l1...Eye, l2...Cam frame, 13...Gear portion, l4...Motor, 15...・Gear, l6...
Cam groove, l7... objective lens holding frame, I8... lth
Cam follower, l9... Oblique guide, 20... Positive lens, 21... Holding frame, 22... Second cam follower, 23... Straight guide, 24... Objective lens, 25
...Objective lens holding frame, 26...Lens barrel, 2 7
．． 3 6...Link lever, 2 8, 2 9, 3 0
．． 3 2... Pin, 3l... Disc, 33... Connection lever, 34... Motor, 35... Spring, 37...
・Cam groove patent applicant Minolta Camera Co., Ltd. Agent
Person Patent attorney Aoyama Aoyama (and other names) Atsushi 2 Figure 3

Claims (1)

[Claims] (1) In a finder of a camera equipped with a photographing optical system capable of selecting a normal photographing position and a macro photographing position, and a finder optical system comprising an objective lens (2) and an eyepiece lens (10), the above-mentioned When selecting the normal photographing position of the photographing optical system, the objective lens (2) is positioned at the first position (I) on the optical axis in order to form an image on a predetermined imaging plane (4, 7), while the photographing optical system When selecting the macro shooting position of the system, the optical path of the subject is refracted to correct parallax, and at the same time the light beam is directed to the above imaging plane (
4, 7) in order to correct the diopter by converging the objective lens (2) to a second position (II) located perpendicular to the optical axis and in front of the optical axis with respect to the first position (I). The objective lens drive mechanism (12, 13, 14, 15, 1
6, 17, 18, 19).