JPH0786631B2 - Zoom finder device - Google Patents

Description

The present invention relates to a finder device for a camera using a zoom lens as a taking lens.

[Conventional technology]

Some recent compact cameras use a zoom lens as a photographing lens. In such a camera, it is usual to use a zoom finder as the finder. Then, the zoom finder is also scaled in association with the zooming of the taking lens so that a viewfinder field corresponding to the angle of view of the taking lens can be obtained.

Generally, in a lens shutter type compact camera, a finder parallax occurs because the optical axis of the finder system does not coincide with the optical axis of the taking lens system. Conventionally, in order to correct this viewfinder parallax, a plurality of view field frames for displaying a shooting range within the viewfinder field are provided according to the shooting distance, or a view field defining the viewfinder field corresponding to the shooting distance. The device is designed to move the mask.

[Problems to be Solved by the Invention]

However, the conventional parallax correction considers only the shooting distance, and no measures are taken for the parallax correction that occurs with a change in the viewfinder magnification. In other words, if a zoom lens is used for the shooting lens system and the viewfinder system is also configured with a zoom viewfinder, changing the viewfinder magnification causes a viewfinder parallax even if the shooting distance is kept constant. Come on.

FIGS. 6A and 6B show a state in which the zoom finder 1 is set at the telephoto end (finder magnification β ₁ ) and the wide-angle end (finder magnification β ₂ : where β ₂ <β ₁ ), respectively. . The finder optical axis 6a of the zoom finder 1 is parallel to the optical axis of the zoom lens 4 for photographing.

As shown in FIG. 3A, when the zoom finder 1 is set at the telephoto end, the chief ray L ₀ from the center of the shooting screen at a shooting distance of 3 m is incident on the objective side of the zoom finder 1 at an angle of incidence. It is incident at θ and emerges from the eyepiece side at an angle of β ₁ · θ. Then, the finder screen center P _T is set on the basis of this main optical axis L ₀ , and the finder field frame 2 is determined on the basis of this screen center P _T.

As described above, in general, the finder screen center P _T of the zoom finder 1 and the field frame 2 are often set on the basis of the shooting distance around 3 m which is frequently shot at the telephoto end as described above. The viewfinder screen center P _T and the field of view 2 determined in this way are different from the screen center P _{0 and the} real field of view 3 determined by the chief ray from infinity, but this is not a problem in practical use. Absent.

However, as shown in FIG. 6B, when the zoom finder 1 is set at the wide-angle end, the chief ray L ₀ from the center of the shooting screen at a shooting distance of 3 m is emitted from the eyepiece side at an angle of β ₂ · θ. . Therefore, the viewfinder screen center P _W at the wide-angle end is located below the screen center P _T at the telephoto end.
This shift amount is the largest at the wide-angle end, and becomes larger as the difference between the finder magnifications at the telephoto end and the wide-angle end increases.

FIG. 7 shows a general zoom finder having a zoom ratio of about 2 times. When the viewfinder screen center P _T is determined according to FIG. 6A, the viewfinder screen center P _T is It shows how the viewfinder is shifted with respect to the center of the shooting screen, and the straight lines A and B represent the states when the zoom finder 1 is set at the telephoto end and the wide-angle end, respectively.

As described above, the viewfinder screen center P _T is set based on the shooting state at the telephoto end and the shooting screen center at a shooting distance of 3 m.
At 3 m, there is no absolute parallax between the shooting screen center and the finder screen center P _T. Then, at a shooting distance other than 3 m, parallax occurs between the viewfinder screen center P _T and the shooting screen center. For example, at a shooting distance closer to 3 m, the shooting screen center is above the viewfinder screen center P _T. In FIG. 7, a minus (-) parallax is shown when the viewfinder screen center P _T is shifted upward with respect to the shooting screen center at each distance position, and a plus (+) is shown when the viewfinder screen center P _T is shifted downward. The parallax is used, and the shift amount between the two is expressed as a percentage in the vertical direction of the field frame 2.

Further, as indicated by the straight line B, even when the zoom finder 1 is set at the wide-angle end, the center of the photographing screen at the infinite distance position is determined by the finder optical axis 6a. Therefore, the absolute parallax between the viewfinder screen center P _T is -4.5% as with the straight line A, and is relative to the viewfinder screen center P _T determined as shown in FIG. 6 (A). Parallax is gone. However, as is clear from Fig. 7, 3m, which has a high shooting frequency,
A parallax of about -2% occurs at a shooting distance in the vicinity, and the parallax becomes larger as the distance becomes closer.

As described above, when the magnification of the zoom finder 1 is changed, a parallax relative to the finder screen center P _T and the field frame 2 set in advance in the finder system is generated. It will move up and down. As a result, the subject moves with respect to the visual field frame 2 and the target mark for the autofocus device, which makes it difficult to perform framing and focusing. Moreover, this adverse effect becomes significant at a shooting distance of 3 m or less, where shooting is frequently performed.

The present invention has been made in view of such a background, and reduces the finder parallax that occurs with the change of the finder magnification by the declination effect of the variable magnification lens that is shifted corresponding to the change of the finder magnification, An object of the present invention is to provide a zoom finder device in which the center of the screen in the field of view of the finder does not move significantly.

[Means for Solving the Problems]

In order to solve the above problems, the present invention provides a variable power lens that is moved back and forth along the optical axis of the finder between the finder objective lens and the eyepiece for variable power of the finder, and this variable power lens is used for zooming of the taking lens. The zoom finder is composed of a moving mechanism for moving back and forth in conjunction with the zoom lens and a shift mechanism for shifting the variable power lens when the variable power lens moves forward and backward.

[Action]

According to the above configuration, when the magnification varying lens is moved back and forth according to the magnification variation of the finder, the magnification varying lens is also shifted with respect to the optical axis of the taking lens. This shift of the zoom lens makes it possible to correct the shake of the viewfinder optical axis due to the change of the viewfinder magnification, and the viewfinder screen center at the wide-angle end side is extremely different from the viewfinder screen center set at the telephoto end. It is possible to keep the center of the viewfinder screen at a practically constant position regardless of the viewfinder magnification.

Hereinafter, an embodiment of the present invention will be described in detail.

〔Example〕

Referring to FIG. 5 showing the appearance of a camera using the finder device of the present invention, a fixed barrel 3 is attached to the front surface of a camera body 2, and a movable barrel 5 holding a zoom lens 4 for shooting moves in and out. It is freely incorporated. Fixed tube 3
Above the window is a viewfinder window 6, distance measuring window for autofocus
7a and 7b are provided. A zoom finder is built in the back of the finder window 6, and the finder optical axis 6a is parallel to the optical axis 4a of the zoom lens 4. Also, the distance measuring windows 7a, 7
A transmitter and receiver for distance measurement are housed in the back of b.

The seesaw knob 8 for zooming is normally in the illustrated neutral position. When the index "T" side is pressed, the zoom lens 4 is zoomed toward the telephoto side only during the pressing, and when the index "W" side is pressed, the zoom lens 4 is zoomed toward the wide-angle side. When the zoom lens 4 is zoomed toward the telephoto end, the movable barrel 5 is moved forward. When zooming of the zoom lens 4 is performed, the zoom finder is also zoomed in conjunction with this, and a subject image according to the angle of view of the zoom lens 4 is observed from the eyepiece. Of course, if the pressing of the seesaw knob 8 is released during the magnification change, each of the zoom lens 4 and the zoom finder stops the magnification change at that time. Then, when the shutter button 9 is pressed, a distance measuring projector / receiver provided at the back of the distance measuring windows 7a and 7b operates to perform distance measurement, and the zoom lens 4 is focused in the movable barrel 5. Shooting is done after it is done.

In FIG. 1 showing an outline of the finder device, a finder frame 11 formed by plastic molding is
A finder accommodating portion 12 and accommodating portions 13 and 14 for mounting a light emitter / receiver of an auto focus device are formed.

The finder housing 12 includes an objective lens 15, a zoom lens 16, a correction lens 17, a reticle 18,
Eyepiece 19 is stored. Variable magnification lens 16 is lens frame 20
The finder optical axis 6a is held by the moving mechanism described later.
Is retreated along. Further, the other lenses 15, 17, 19 and the reticle 18 are fixed to the finder frame 11. Reticle
As is well known, reference numeral 18 indicates a viewfinder field frame, a target mark for autofocus, and the like.

A slot 21 parallel to the finder optical axis 6a is formed on the bottom surface of the finder housing portion 12, and a pin 22 integrated with the lens frame 20 penetrates the slot 21. In addition, a guide side 24 that is slanted low toward the objective lens 15 side is integrally formed on the side wall that defines the finder housing portion 12. The guide side 24 regulates the vertical position of the lens frame 20 when the lens frame 20 moves back and forth. That is, as shown in FIG. 2, the side wall of the lens frame 20 is formed with a convex side 25 and a protrusion 26 that vertically sandwich the guide side 24.
26 slides on the guide side 24 to perform a guiding function. Also,
A pair of protrusions 27 is also formed on the other side wall of the lens holding frame 20, so that the guide side formed on the other side wall of the finder accommodating portion 12 is vertically sandwiched.

A mounting plate 30 is fixed to the bottom surface of the finder frame 11. The mounting plate 30 is provided with a guide slot 30b orthogonal to the finder optical axis 6a, an arcuate slot 30c, a slot 30d parallel to the finder optical axis 6a, and a notch 30e. In addition, to fix the mounting plate 30,
A pair of projecting pieces 30a integrally formed with 30 are inserted into holes formed in the bottom surface of the finder frame 11, and the other end of the mounting plate 30 is screwed to the boss 31. Since the boss 31 projects downward and the rising portion is formed at the end of the protruding piece 30a, the mounting plate 30 is fixed to the bottom surface of the finder frame 11 with a predetermined gap.

A cam plate 35 is mounted between the finder frame 11 and the mounting plate 30. The cam plate 35 has a cam slot 35a,
An elongated hole 35b and a projecting piece 35c are formed. Then, the protruding piece 35c is inserted into the notch 30e of the mounting plate 30, and the cam plate 35 is slidably mounted on the mounting plate 30 laterally by the pair of caulking pins 36 inserted into the guide slots 30b of the mounting plate 30. To be done. The pin 22 protruding from the slot 21 formed on the bottom surface of the finder frame 11 is engaged with the cam slot 35a.

The frame integrated inside the camera body 2 has a shaft
A fan-shaped gear 41 that rotates around 40 is mounted on the shaft.
The fan-shaped gear 41 meshes with the interlocking gear 42. Interlocking gear
The motor 42 is rotated counterclockwise by the motor when the index "T" side of the seesaw knob 8 (Fig. 5) is pressed, and the zoom lens 4 for photographing is adjusted to the telephoto side via the variable power mechanism 43. . Further, when the index “W” of the seesaw knob 8 is pressed, the interlocking gear 42 rotates clockwise to adjust the zoom lens 4 to the wide angle side.

A drive lever 45 is provided coaxially with the sector gear 41. The drive lever 45 engages with the pin 41a fixed to the fan gear 41 and rotates together with the fan gear 41. An interlocking pin 45 is planted in the drive lever 45. This interlocking pin 46
Penetrates an arcuate slot 30c formed in the mounting plate 30 and is inserted into an elongated hole 35b of the cam plate 35. Since the slot 30c is formed in an arc shape around the shaft 40, it does not hinder the rotation of the drive lever 45.

The operation of the finder device having the above configuration is as follows.

When the seesaw knob 8 is pressed from the neutral position shown in FIG. 5 toward the index “W” side, the zooming motor is activated and the interlocking gear 42 rotates clockwise as indicated by the arrow. When the interlocking gear 42 rotates in the clockwise direction, the variable power mechanism 43 operates toward the wide angle side, and the zoom lens 4 for photographing is operated.
Adjust toward the wide-angle side.

In this way, in the process in which the zoom lens 4 is adjusted to the wide-angle side, the fan gear is rotated by the clockwise rotation of the interlocking gear 42.
41 rotates counterclockwise. As a result, the drive lever 45 also rotates counterclockwise via the pin 41a. Along with this, when the interlocking pin 46 is displaced counterclockwise, the cam plate 35 slides leftward through the elongated hole 35b. The slide of this cam plate 35 consists of the guide slot 30b, the crimp pin 36, and the notch 3
Guided by 0e and projection 35c.

When the cam plate 35 slides to the left, the pin 22 fixed to the lens frame 20 is pushed forward by the cam slot 35a. As a result, the lens frame 20 holding the variable power lens 16 is moved from the position shown by the solid line in FIG. 3 to the position shown by the chain double-dashed line, that is, the position close to the objective lens 15.

When the lens frame 20 is moved forward, by the sliding contact between the convex side 25, the protrusion 26 and the guide side 24, and further by the sliding contact between the pair of protrusions 27 and the guide side formed on the other side wall of the finder housing portion 12, The lens frame 20 is below, that is, the optical axis 4a of the zoom lens 4.
Is shifted to approach. This shift amount is determined in accordance with the amount of movement of the lens frame 20, in other words, the magnification of the zoom lens 4 and the zoom finder.

FIG. 4 illustrates the above-described operation for the optical system of the zoom finder. FIG. 4A shows the zoom lens 16 at the telephoto end, and FIG. 4B shows the zoom lens 16 at the wide-angle end. It shows a certain state. Lens frame 20 by zooming to the wide-angle side
Is shifted downward while advancing, so that the variable power lens 16 is gradually advanced downward while advancing. Then, at the wide-angle end, the variable power lens 16 is moved downward by the shift amount d with respect to the position at the telephoto end.

In this way, when the zoom lens 16 is shifted to approach the optical axis 4a in the process of zooming the zoom finder to the wide-angle side, the wedge action of the zoom lens (concave lens) 16 causes
The finder optical axis 6a will be deflected upward. Therefore, at the wide-angle end in FIG.
When the chief ray L ₀ from the center of the shooting screen at 3 m exits from the eyepiece 19, the exit angle is β ₂ · θ or more. Then, by properly setting the shift amount d, the main optical axis L ₀ can be made to coincide with the screen center P _T at the telephoto end.

In addition, even in the intermediate viewfinder magnification between the telephoto end and the wide-angle end, by appropriately changing the shift amount of the zoom lens 16, for a shooting distance of 3 m, the chief ray from the center of the shooting screen is displayed at the telephoto end. It can be matched to the center P _T. Therefore, the shapes of the guide side 24, the convex side 25, and the protrusion 26 are determined in consideration of the shift amount at the intermediate magnification. Of course, when the amount of movement and the amount of shift of the variable power lens 16 are non-linear, these sliding contact parts are formed in a curved shape.

The parallax correction effect by shifting the variable magnification lens 16 is
This means that the straight line B is translated to the position of the straight line B'in FIG. Therefore, the difference between the parallax at the telephoto end (straight line A) and the corrected parallax at the wide-angle end (straight line B ') can be reduced in most of the shooting distance range. The "shooting distance-parallax" straight line in the intermediate magnification range intersects with the straight line A at a shooting distance of 3 m, and the inclination is represented as a straight line having a value between the straight line A and the straight line B. It can be seen that the parallax is corrected well also in these cases.

In the above embodiment, the viewfinder screen center P _W at the wide-angle end is made to match the viewfinder screen center P _T at the telephoto end, but conversely, the viewfinder screen center P _W at the wide-angle end is matched with the viewfinder screen center P _W at the telephoto end. It is also equivalent to match the screen centers P _T. Further, according to the present invention, the parallax due to the zooming of the zoom finder is corrected only by the shift of the zooming lens 16, and no complicated structure is required, so that the parallax due to the change of the shooting distance is corrected. For example, it is possible to incorporate a visual field frame switching mask or the like.

By tilting the entire zoom finder, aligning the finder optical axis of the zoom finder with the center of the shooting screen at a shooting distance of 3 m, and setting the finder screen center on this finder optical axis, a shooting distance of 3 m will be obtained regardless of the viewfinder magnification. Can eliminate parallax. However, even with such a configuration, at the shooting distances other than 3 m, the center of the shooting screen at each shooting distance position deviates from the set center of the screen of the finder, and the shift amount is still the viewfinder magnification. It corresponds to. Therefore, the present invention in which the deviation amount is suppressed by the declination effect of the variable power lens can be similarly applied to the zoom finder having such a configuration.

〔The invention's effect〕

As described above, according to the zoom finder device of the present invention, not only the variable magnification lens that is moved when changing the finder magnification is moved in the finder optical axis direction, but also the finder optical axis is shifted. By doing so, the parallax caused by changing the finder magnification is corrected. Therefore, the subject image does not extremely move within the viewfinder field during zooming of the viewfinder, and the framing operation or the focusing operation by the distance measuring area displayed in the viewfinder is facilitated.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing one embodiment of a zoom finder device using the present invention. FIG. 2 is an external view of the lens holding frame. FIG. 3 is a partial sectional view of the zoom finder device shown in FIG. 4 (A) and 4 (B) are explanatory views showing a state in which the optical system of the device of the present invention is set at the telephoto end and the wide-angle end, respectively. FIG. 5 is an external view of a camera using the present invention. FIGS. 6A and 6B are explanatory views when the conventional zoom finder is set at the telephoto end and the wide-angle end, respectively. FIG. 7 is a graph showing the correlation between the shooting distance and the parallax. 4 …… Zoom lens 11 …… Finder frame 16 …… Variable lens 20 …… Lens frame 24 …… Guide side 30 …… Mounting plate 35 …… Cam plate 45 …… Drive lever.

Claims (1)

[Claims] 1. A variable power lens movably provided between a viewfinder objective lens and an eyepiece, and a moving mechanism for moving the variable power lens forward and backward along an optical axis of the viewfinder in conjunction with zooming of a taking lens. And a shift mechanism for shifting the optical axis of the variable power lens so that the optical axis of the variable power lens approaches or moves away from the optical axis of the photographing lens when the variable power lens is moved back and forth.