JPH02309331A - Finder for camera - Google Patents

Abstract

PURPOSE:To perform the compensation of parallax and the correction of diopter with extremely simple constitution and to miniaturize a finder by advancing and retreating a correcting lens with respect to a specified position on the optical axis of a finder optical system at the time of selecting the macro photographing position of a photographing optical system. CONSTITUTION:The optical path of the finder optical system provided separately from the photographing optical system has such constitution that light reaches a pupil 11 through an objective lens 2, a 1st condenser lens 3, a relay optical system 6, a 2nd condenser lens 9 and an ocular 10. At the time of selecting the macro photographing position of the photographing optical system, the correcting lens 1 is inserted on an optical axis 13 ahead of the objective lens 2 to refract the optical path 13 and the parallax is compensated. At the same time, the diopter is corrected by changing the convergence rate of luminous flux and shifting an image-formation surface from a position 5, 8 to a position 4, 7. Namely, in the case of performing the macro photographing, a holding member 23 is rotated by a motor 22 and a close-up lens 21 is positioned on the optical axis 20 of the photographing optical system, then the correcting lens 1 is rotated with a holding member 29 through gears 26 and 27 to be positioned on the optical axis 13 of the finder optical system.

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 section M]

More than ever! In cameras other than eye lenses, the finder optical system is generally configured with an optical axis separate from that of the photographic optical system. Therefore, for example, when light heads toward a camera from an arbitrary point on the optical axis of the photographic optical system, an image is formed on the optical axis in the photographic optical system, but in the finder optical system, the image is formed at a position offset from the optical axis. . This fluctuation of the image formation position, or vararax, is so small that it does not pose a problem when the distance between any one point and the image formation plane is extremely far, but it increases as the distance approaches, and it becomes larger as the distance approaches the center of the imaging range. The deviation from the center of the viewfinder field of view also 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. 10A and 10B, there is a structure in which a field frame 50 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. For example, if the photographer is someone who has little interest in cameras, he or she may take macro shots without even knowing that the shooting range must be aligned with the macro photography field frame drawn in the viewfinder. In some cases. 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
The technique is disclosed in Japanese Patent Application Laid-open No. 36, Japanese Patent Application Laid-Open No. 6K 52114, and Japanese Utility Model Application No. 63-705.39, etc., but in all of these, a prism is placed on the objective lens side of the finder optical system. Vararax is corrected by utilizing the refraction of light by this prism. On the other hand, single-lens reflex cameras are configured so that the image is always focused on the image forming plate even if the shooting distance changes, so the image of the subject is always viewed at the same position in the viewfinder. I can do it. Therefore, since the distance between the photographer's pupil and the imaging position does not change, it can be said that the degree of perspective, that is, the diopter of the image, is always constant. However, in cameras that have separate photographic optical systems and finder optical systems as described above, the viewfinder optical system generally does not change depending on the photographing distance, so if the photographing distance changes, The imaging position also changes. That is, the diopter changes. Especially when the diopter changes greatly, such as when performing macro photography,
No focused images can be seen within Hunaindar. Therefore, in order for the photographer to see an appropriate image when performing macro photography, it is necessary to correct the diopter as well as correct the parallax. However, if these are corrected by separate means, the configuration becomes complicated and the finder becomes large, which is not preferable. The present invention was devised to effectively solve such conventional technical problems. Therefore, its purpose is
The purpose of this invention is to perform vararax correction and diopter correction with an extremely simple configuration, that is, with one solution, or in terms of aesthetics, with one optical element.

[Means to solve the problem]

Balarax and diopter h1 of finder according to the present invention
In order to achieve the above-mentioned object, the eleventh means is constructed as follows. First, the invention according to claim 1 comprises a photographing optical system capable of selecting a normal photographing position and a macro photographing position, an objective lens and an eyepiece, and a predetermined result when selecting a normal photographing position of the photographing optical system. This invention is related to the fineness of a camera having a finder optical system that forms an image on the image plane, and is characterized by the following configuration. In other words, when selecting the macro shooting position of the photographic optical system, by positioning it either in front or behind the objective lens, the optical path of the subject is refracted to correct for vararax, and at the same time, the convergence rate of the light beam is changed to direct the lens to the above-mentioned imaging plane. It includes a correction lens that corrects the diopter for image formation, and a drive means that moves the correction lens forward and backward with respect to a predetermined position on the optical axis of the finder optical system in accordance with the photographing position of the photographic optical system. The invention according to claim 2 relates to a finder of a camera, which includes 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 lens. It features the following configuration. That is, the objective lens includes a first objective lens that is inserted into the finder optical system and configured to form an image on a predetermined imaging plane when the photographing optical system normally selects the photographing position, and a first objective lens that is configured to be inserted into the finder optical system to form an image on a predetermined imaging plane when the photographing optical system normally selects the photographing position. A second objective lens, which is sometimes inserted into the Finder optical system, refracts the optical path of the object to correct the vararax, and at the same time changes the convergence rate of the light beam to correct the diopter so as to form an image on the image forming plane. It further includes a driving means for selectively positioning one of the objective lenses at a predetermined position on the optical axis of the finder optical system in accordance with the photographing position of the photographing optical system.

[Action/effect]

Claim: In the configuration of this invention, when the photographing optical system is selected at the normal photographing position, the correction lens is moved by the driving means from a predetermined position on the optical axis of the finder optical system, that is, from either the front or rear position of the objective lens. evacuate. Therefore, the image is formed on a predetermined imaging plane within the field of view of the finder. When the macro photographing position is selected for the photographing optical system, the correction lens is inserted by the driving means into a predetermined position on the optical axis of the finder optical system, that is, at either the front or rear position of the objective lens. At this time, for example, when light heading toward the camera from an arbitrary point on the optical axis of the photographic optical system passes through this correction lens, it is refracted and at the same time the convergence rate changes, forming an image on the above-mentioned predetermined imaging plane. Vararax and diopter are corrected as much as possible. Therefore, with this finder, it is possible to clearly see the appropriate photographing range in the macro photographing state. In the configuration of the invention according to claim 2, when the photographing optical system is selected to the normal photographing position, the first objective lens is selected as the objective lens and moved to a predetermined position on the optical axis of the finder optical system. inserted into. At this time, the image is formed at a predetermined imaging position. On the other hand, when the photographing optical system selects the macro photographing position, the second objective lens is selected and inserted at a predetermined position on the optical axis of the finder optical system. At this time, for example, light heading toward the camera from an arbitrary point on the optical axis of the photographing optical system is refracted when passing through this second objective lens, and at the same time, the convergence rate changes, and the light is directed to the above-mentioned predetermined imaging plane. Balarax and diopter are corrected to form an image. Therefore, in this case as well, the appropriate photographing range in the macro photographing state can be clearly seen. As described above, according to each of the above configurations, vararax and diopter are corrected using only one optical element, that is, the correction lens in the configuration of claim 1, and the second objective lens in the configuration of claim 2, Can be done at the same time. Therefore, it is possible to simplify the configuration of the finder that allows a clear view of an appropriate image corresponding to the photographing range, and further downsize the finder.

【Example】

The embodiments of the invention shown in FIGS. 1 to 9 will now be described in detail. First, based on FIG. 1, the optical path of the finder according to the first embodiment will be explained. 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 a correction lens 1, an objective lens 2, a first condenser lens 3, and a relay optical system 6.
, a second condenser lens 9, and an eyepiece lens 10. Note that 4 and 7 indicate the imaging planes,
One of these is provided with a viewing frame (not shown). When performing macro photography with a camera in which the finder optical system is configured separately from the photographic optical system in this way, the light flux heading 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. It is incident at a certain angle. If the correction lens I is not provided, the incident light travels along the broken line, first forms an inverted image at the position 5, passes through the relay optical system 6, and forms an erect image at the position 8. do. In this case, in addition to the occurrence of parallax depending on the angle of incidence, the object is closer to the subject than in normal photography, so the elephant is in the image planes 4 and 7, which are normally used for clear viewing.
The images are formed at positions shifted toward the pupil 1 and 1, respectively. Therefore, a diopter deviation t occurs. On the other hand, a correction lens 1 configured as a positive lens by forming a wedge shape with one side spherical on the front surface of the objective lens 2.
When the camera is positioned at Image. In other words, parallax and diopter are corrected simultaneously using four lenses. Note that the correction lens l can also be located behind the objective lens 2, as shown by a virtual line 12. By doing so, even if the h(i positive lens 1 is added), the overall length of the optical system does not change, and the finder can be made more compact.In addition, in this embodiment, the image Although the relay optical system 6 is used to perform the reversal in the lower and left-right directions, it is also possible to use a Porro prism or a so-called Boro mirror that is an equivalent optical system formed of a reflecting mirror instead of the relay optical system. The outer peripheral shape of the correction lens is not limited to that shown in Fig. 1, but can be made into various shapes.The shape is shown in Fig. 3.The shape shown in Fig. 3A is is the correction lens 1 in Fig. 1, the front side is the Taber surface,
This is a correction lens formed as a spherical surface having its center on the optical axis 13 on the back side. What is shown in FIG. 3B is a correction lens 15 in which the curved side is a plane perpendicular to the optical axis 13, and the back side is formed as a spherical surface whose center is shifted downward from the optical axis I3. What is shown in FIG. 3C is a correction lens 16 in which the front surface is formed as a spherical surface centered on the optical axis 13, and the back surface is formed as a Taber surface. What is shown in FIG. 3D is an ha positive lens 17 whose front side is formed as a spherical surface whose center is shifted downward from the optical axis 13, and whose back side is formed as a plane perpendicular to the optical axis 13. What is shown in FIG. 3E is a spherical surface whose front side is centered at a position shifted downward from above the optical axis 13;
The front side is a Mi positive lens 18 formed as a spherical surface having its center on the optical axis 13. Since each of these lenses is a positive lens formed in a wedge shape as a whole, by placing them before and after the objective lens 2, it is possible to simultaneously change the degree of convergence and refraction of light. Therefore, by using a correction lens formed into an appropriate wedge shape, parallax and diopter deviation can be sufficiently corrected. Next, the drive mechanism of the correction lens will be explained using FIGS. 4 to 6. In FIG. 4, the second eye is a close amplifier lens that is incorporated into the photographing optical system.This lens 21 is positioned on the optical axis 20 of the photographing optical system to enable macro photography. The figure shows a normal photographing position in which the lens 21 is retracted from above the optical axis 20. The close-up lens 21 is a sector-shaped first lens.
It is fixed to a holding member 23, and this first holding member 23
is rotated via the gear 19 as the motor 22 rotates. The first holding member 23 is formed with an open portion 25 so as to keep the front surface of the objective lens open at all times, and a gear portion 26 and a stopper 51 are formed on both ends of the outer circumferential arcuate surface 24. ing. On the other hand, the correction lens l is held by a second holding member 29 that is swingable about the pin 33. Furthermore, a correction lens drive gear 27 that meshes with a gear portion 26 formed on the first holding member is rotatably supported on the pin 33 . As shown in FIG. 5, projections 32 and 31 are formed on the second holding member 29 and the lens drive gear 27, respectively, and a spring 28 is attached to the pin 33 so that the legs 53 sandwich them. ing. When shifting to macro photography in the above configuration, the motor 22 is operated from the state shown in FIG. 4 to prevent the first holding member 23 from rotating clockwise. As the rotation of the first holding member 23 progresses, the gear portion 26 and the correction lens drive gear 2 will eventually be connected to each other.
7 mesh with each other, and the lens drive gear rotates counterclockwise around the pin 33. Therefore, the protrusion 31 formed thereon causes the spring 28 to rotate in the same direction about the pin 33. Since the projection 32 is pushed by the rotation of the spring 28, H1
i The positive lens l moves toward the optical axis 13 of the finder. The correction lens l is positioned on the front axis 13 when the second holding member 29 comes into contact with the stopper 34 (FIG. 6), but the close amplifier lens 21 holds the first holding member 23 a little further. In the rotated state, it is accurately positioned on the optical axis 20-H of the photographing optical system. Accordingly, the spring 28 is in a state where the leg portions 53 are expanded to some extent, so that a biasing force is generated, and the biasing force holds the correction lens in the correct position. This state is shown in FIG. On the other hand, the transition from macro photography to normal photography is performed by reversing the motor. In this case, as the first holding member 23 rotates counterclockwise, the correction lens drive gear 27 rotates clockwise, so that the spring 28, which had been forced to spread the legs 53, returns to its free state. Then, since the protrusion 31 further rotates in the same direction around the bottle 33, the second holding member 29 rotates clockwise via the spring 28 and the protrusion 32, and the correction lens l is retracted from the position on the optical axis. . When the first holding member 23 rotates to the normal photographing position, the correction lens driving gear 27 is pressed by the stopper 51 and reliably presses the second holding member 27 against the stopper 30 via the spring 28 . Therefore, the correction lens l will not inadvertently advance onto the optical axis 13. This drive #a structure can also be configured as shown in FIGS. 7 and 8 as an example of color variation. In this figure, the correction lens l
is held by a holding stamp material 40 having bins 4I and 52 provided at diagonal positions of a substantially rectangular shape. The bin 41 is engaged with a guide groove 42 provided in the camera's body. On the other hand, one end of a lever 37 is swingably attached to the bin 52, and the central part of the lever 37 is attached to the bin 52. arm 3
One end of 9 is also swingably provided. Lever 3
The curved end of 7 is pivotally supported by a bin 38 provided on the camera side,
The other ends of the three arms are connected to the final gear of the gear train 36. A motor: 35 is connected to this gear train. If this configuration is adopted as the drive mechanism, the motor 35
When the lever 37 is rotated clockwise with the bin 38 as a fulcrum U', the holding member 40 becomes the guide ljη・12
and moves to the right by the action of the bottle 41. Then, when the bottle 41 moves to the right end of the groove 42, as shown in FIG. The Ili positive lens 1 is now located on the optical axis 13. The correction lens 1 is retracted from the optical axis 13 by reversing the motor 35 in the opposite direction to that described above. Note that the spring 43 connected to the holding member 40 is provided to eliminate wobbling of the correction lens. Furthermore, in these figures motor 3
5 is configured to drive only the correction lens 1, but it goes without saying that if the gear train 3G is made into two rows, it can also drive the close-up lens of the photographing optical system. Further, as another modification of the drive mechanism, a cylinder may be used as shown in FIG. 9. Although this figure shows only the main parts, by expanding and contracting the cylinder 44, the lever 45 is moved along the guide 1tft47, and thereby the correction lens l held by the holding member 49 is moved around the bottle 46. It can be swayed. Therefore, as in each of the configurations described above, by aligning one end of the swing with the optical axis 13, the correction lens 1
can be moved forward and backward with respect to the optical axis 13. By configuring the correction lens l and the drive mechanism as in each of the above examples, the imaging position in the viewfinder can be maintained even when the photographing optical system is selected at the normal photographing position or when the macro photographing position is selected. This makes it possible to keep the lens at almost the same location, thereby avoiding the problems of parallax and diopter deviation. Moreover, since these corrections are made with a single lens, the size of the finder is not increased compared to, for example, a finder equipped with only a parallax correction mechanism. Next, a second embodiment will be described using FIG. 2. As shown in the figure, no correction lens is used in this case, and the optical path is corrected by the objective lens 14. Therefore, different objective lenses are used when the photographing optical system selects the normal photographing position and when the macro photographing position is selected. Specifically, the viewfinder objective lens (second objective lens) when the photographing optical system is set to the macro photography position has a higher focal point than the one when the normal photography position is selected (the first objective lens). I'm using one with a short distance. During macro photography, the second objective lens 14 is positioned eccentrically with respect to the optical axis 13. This is because if the second objective lens 14 is arranged in this way, the direction of refraction of light will change compared to when the axes are aligned, and if this property is used,
The light incident at a certain angle with respect to the optical axis 13 is
Vararax can be corrected by changing it in the direction along 3. Since this second objective lens 14 has a shorter focal length than the first objective lens for normal photography, it is possible to focus the image of the subject on a predetermined imaging plane, and this also allows for proper photography. You can clearly see the range. Note that this second objective lens i4 may be a wedge-shaped lens as in the first embodiment (and furthermore, the second objective lens i4 may be a wedge-shaped lens
Various modifications such as those described in the embodiments are also possible. Conversely, as a correction lens in the first embodiment,
Needless to say, an ordinary convex lens can also be used eccentrically with respect to the optical axis. Although the drive mechanism in this configuration is not particularly illustrated, it can be easily realized by, for example, modifying the second holding member 29 in FIG. 4. That is, when the second holding member 29 is in the state shown in FIG.
Another lens may be placed on top, and the second holding member 29 may be configured in an L-shape so as to hold this additional lens as well. Then, use the lens indicated by 1 in the figure as a lens with a short focal length for macro photography (however, it may be necessary to position it eccentrically on the optical axis of the finder optical system).
If the added lens is used for normal photography, the objective lens of the finder optical system will be automatically replaced as the state of the photographic optical system changes. Further, even with the configuration shown in FIG. 7, the same function can be achieved by modifying the holding member 40 to hold two lenses. With this configuration, balarax and diopter deviation will not become a problem as in the first embodiment (in addition, there is no need to place a correction lens in front of the objective lens). It becomes possible to achieve miniaturization.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the schematic structure and optical path of a finder according to the first embodiment of the present invention, FIG. 2 is a schematic diagram showing the schematic structure and optical path of the finder according to the second embodiment of the present invention, and FIG. 3E are external views showing modified examples of the correction lens constituting the finder according to the first embodiment of the present invention, FIG. 4 is a front view showing the correction lens drive mechanism during normal shooting, and FIG. FIG. 4 is an enlarged view of the V section; FIG. 6 is a front view showing the correction lens drive mechanism during macro photography; FIG. 7 is a front view of the correction lens drive mechanism according to the first modification during normal photography; FIG. 8 is a front view showing the same state during macro photography, FIG. 9 is a front view showing the correction lens drive mechanism according to the second modification, and FIGS. 10A and 10B show the field frame provided in a conventional finder. This is a schematic diagram. 1.12,15,16.17,18...correction lens, 2
...Objective lens, 3.9...Condenser lens, 4.
5,7.8... Image forming surface, 6... Relay optical system, 10
...Eyepiece lens, 11...Pupil, 13...Finder optical system optical axis, [4...Second objective lens, 19.
Gear, 20... Optical axis of photographing optical system, 21... Close-up lens, 22... Motor, 23. First holding member, 24... Outer circumferential arc surface, 25... Opening, 26.・
・Gear part, 27...Correction lens drive gear, 28...
Spring, 29...Second holding member, 30, 34.51...
・Stock bar, 31.32...protrusion, 33...bottle,
35...Motor, 36...Gear train, 37...Lever, 38.4.1...Bin, 39...Arm, 40
...Holding member, 42-Guide groove, 43...Spring, 4
4... Cylinder, 45... Lever, 46... Bin, 47... Guide groove, 48... Spring, 49... Holding member, 50... Viewing frame, 52... Bin , 53...
・Leg patent applicant Minolta Camera Co., Ltd. Agent
Person Patent Attorney Blue and White Sui (and 1 other person) Figure 3A
Figure 3B Figure 3C
Figure 3D Figure 3E

Claims (2)

[Claims] (1) A photographic optical system that allows you to select between a normal photographing position and a macro photographing position, an objective lens (2), and an eyepiece lens (10).
and a finder optical system that forms an image on a predetermined imaging plane (4, 7) when the normal photographing position of the photographing optical system is selected, the macro photographing of the photographing optical system When selecting a position, the objective lens (2) is located either in front or behind the objective lens (2) to refract the optical path of the object and correct parallax, while at the same time changing the convergence rate of the light flux to the imaging plane (4, 7). a correction lens (1) for correcting the diopter so as to form an image; Drive means (19, 22, 26, 2
7, 28, 29). (2) A camera finder comprising 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 and an eyepiece (10), wherein the objective lens is inserted into the finder optical system when selecting the normal photographing position of the photographing optical system, and is positioned at a predetermined imaging plane (4
, 7), which is inserted into the finder optical system when selecting the macro shooting position of the photographing optical system, refracts the optical path of the subject, corrects parallax, and at the same time changes the luminous flux. a second objective lens (14) that corrects the diopter to form an image on the imaging plane (4, 7) by changing the convergence rate of the lens; and align one of the objective lenses with the optical axis (13) of the finder optical system.
Drive means (19, 2) for selectively positioning the top at a predetermined position
2, 26, 27, 28, 29).