JPH01261623A - Zooming finder device - Google Patents

Abstract

PURPOSE:To prevent an object image from moving in the field of a finder in which a variable power is performed by not only making a variable power lens which is moved when a finder magnification is changed move to a finder optical axis direction but also making the said lens shift with respect to a photographing optical axis. CONSTITUTION:The title device is provided with the variable power lens 16 to advance and retreat along the finder optical axis 6a between a finder objective lens 15 and an eyepiece 19 in order too perform the variable power of the finder, a moving mechanism to make the variable power lens 16 advance and retreat while interlocking the zooming of a photographing lens, and a shifting mechanism to shift the lens 16 when the variable power lens 16 is advanced and retreated. Consequently, the blurring of the finder optical axis 6a accompanied by the change of the finder magnification can be corrected by the shifting of the variable power lens 16. Thus, the center of a finder image plane in a wide angle end side is not extremely deviated and the center of the finder image plane can be almost kept practically a certain position regardless of the finder magnification.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a finder device for a camera using a zoom lens as a photographing lens.

[Conventional technology]

Some recent compact cameras use a zoom lens as a photographic lens. In such cameras, a zoom finder is also normally used as the finder. The zoom finder also changes magnification in conjunction with the zooming of the photographic lens, so that a finder field of view corresponding to the angle of view of the photographic lens can be obtained.

Generally, in a lens-shutter type compact camera, finder parallax occurs because the optical axis of the finder system does not coincide with the optical axis of the photographing lens system. Conventionally, in order to correct this finder parallax, multiple field frames were provided to display the shooting range within the viewfinder field of view, depending on the shooting distance, or a field of view that defined the finder field of view according to the shooting distance was used. Efforts are being made to move the mask.

[Problem to be solved by the invention]

However, conventional parallax correction takes only the photographing distance into consideration, and no countermeasures are taken for parallax correction that occurs with changes in finder magnification. In other words, if a zoom lens is used as the photographic lens system and the finder system is also configured with a zoom finder, finder balax will occur when the viewfinder magnification is changed, even if the shooting distance remains constant. It's coming.

6A and 6B show the zoom finder 1 set at the telephoto end (finder magnification β1) and the wide-angle end (finder magnification β2, where β2<βl), 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 Figure (A), when the zoom finder 1 is set at the telephoto end, the principal ray L0 from the center of the photographic screen when the photographing distance is 3 m is incident on the objective side of the zoom finder l at an incident angle θ. The incident angle is β1・θ from the eyepiece side.
eject at an angle of

Then, a finder screen center P is set based on this chief ray L0, and a finder field frame 2 is determined based on this screen center PT.

In this way, the viewfinder screen center P and the field frame 2 of the zoom finder 1 are generally set based on the photographing distance of around 3 m, which is frequently photographed at the telephoto end, as described above. Note that the finder screen center P and field frame 2 determined in this way are different from the screen center P and the actual field of view 3 determined by the chief ray from infinity, but this is not a problem in practice. Not good.

However, as shown in Figure (B), when the zoom finder 1 is set at the wide-angle end, the principal ray from the center of the photographic screen at a photographing distance of 3 m. is emitted from the eyepiece at an angle of β2·θ. Therefore, the center P8 of the finder screen at the wide-angle end C is shifted downward from the center P7 of the screen at the telephoto end. This amount of deviation is greatest at the wide-angle end, and increases as the difference in finder magnification between the telephoto end and the wide-angle end increases.

FIG. 7 shows the viewfinder screen center Pt when the finder screen center Pa is determined according to FIG.
shows how it is observed through the finder with respect to the center of the photographic screen at each photographing distance, and the straight line A,
B represents the state when the zoom finder 1 is set at the telephoto end and the wide-angle end, respectively.

As mentioned above, the center P of the finder screen is set based on the center of the shooting screen when the telephoto end is set and the shooting distance is 3 m. Screen center and finder screen center PT
There is no absolute variance between the two. And 3m
At shooting distances other than the above, variations occur between the center of the shooting screen and the center of the finder screen Pr. For example,
At a shooting distance closer than 3 m, the center of the shooting screen is above the finder screen center PT. In Fig. 7, the case where the center P of the finder screen deviates upwards from the center of the photographic screen at each distance position is a negative (-) vararax, and the case where it deviates downwards is a positive (+) vararax. The amount of deviation between the two is expressed as a percentage in the vertical direction of the visual field frame 2.

Furthermore, as shown by straight line B, even when the zoom finder 1 is set at the wide-angle end, the center of the photographic field at an infinite distance position is determined by the finder optical axis 6a. Therefore, the absolute disparity between the center PT of the finder screen and the center PT is -4,5 as with the straight line A.
%, and there is no relative variation at 7 with respect to the finder screen center PT determined as shown in FIG. 6(A).

However, as is clear from FIG. 7, a variation of about 12% occurs at a shooting distance of around 3 m, where shooting is frequently performed, and the variation increases as the distance gets closer.

In this way, by changing the magnification of the zoom finder 1, the finder screen center PT, which is preset in the finder system,
When a relative variax occurs with respect to the field frame 2, the subject moves up and down within the viewfinder field of view. As a result, the subject moves with respect to the field frame 2 and the target mark for the autofocus device, making framing and focusing difficult. Moreover, this problem becomes more noticeable at a shooting distance of 3 m or less, which is a frequent shooting distance.

The present invention has been made in view of this background, and it reduces finder balax that occurs due to changes in finder magnification by using the declination effect of a variable magnification lens that is shifted in response to changes in finder magnification. To provide a zoom finder device in which the center of a screen within a finder field of view does not move significantly.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a variable magnification lens that is moved forward and backward along a finder optical axis between a finder objective lens and an eyepiece to change the magnification of the finder; A zoom finder is constructed from a moving mechanism for moving the variable power lens forward and backward in conjunction with the zooming of the photographic lens, and a shift mechanism that shifts the variable power lens when the variable power lens is moved forward and backward.

[Effect]

According to the above configuration, when the variable magnification lens is moved forward or backward in response to variable magnification of the finder, the variable magnification lens is also shifted relative to the optical axis of the photographic lens. By shifting this variable magnification lens, it is possible to correct the deflection of the viewfinder optical axis caused by changing the viewfinder magnification, and the center of the viewfinder screen at the wide-angle end is extremely different from the center of the viewfinder screen set at the telephoto end. The center of the finder screen can be kept at a practically constant position regardless of the finder magnification.

An embodiment of the present invention will be described in detail below.

〔Example〕

In 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 of the camera body 2, and a movable barrel 5 holding a zoom lens 4 for photographing moves back and forth within the fixed barrel 3. It is freely incorporated. Fixed cylinder 3
Above the viewfinder window 6. Distance measuring windows 7a and 7b for autofocus are provided. A zoom finder is built into 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.

Further, behind the distance measurement windows 7a and 7b, there is a projector for distance measurement.

Contains a light receiver.

The zooming seesaw knob 8 is normally in the neutral position shown. When the index "T" side is pressed, the zoom lens 4 is zoomed toward the telephoto side only during the pressing period, and when the index "WJ side is pressed, the zoom lens 4 is zoomed toward the wide-angle side.

Note that when the zoom lens 4 is zoomed toward the telephoto end, the movable barrel 5 is moved forward. When the zoom lens 4 changes its magnification, the zoom finder also changes its magnification in conjunction with this, and a subject image corresponding to the angle of view of the zoom lens 4 is observed from the eyepiece. Of course, if the pressure on the seesaw knob 8 is released during magnification change, each of the zoom lens 4° zoom finder stops changing magnification at that point. Then, when you press shutter button 9,
The projector/receiver for distance measurement provided at the back of the distance measurement windows 7a and 7b is activated to measure the distance, and after the zoom lens 4 is focused within the movable barrel 5, photographing is performed.

In FIG. 1, which schematically shows a finder device, a finder frame 11 made by plastic molding is formed with a finder accommodating portion 12 and accommodating portions 13 and 14 for attaching the projector/receiver of an autofocus device.

The finder accommodating portion 12 includes an objective lens 15 that constitutes a zoom finder. Variable magnification lens 16. Correction lens 17.
Reticle 18. The eyepiece 19 is housed. The variable magnification lens 16 is held by a lens frame 2o, and is moved forward and backward along the finder optical axis 6a by a moving mechanism to be described later. Further, the other lens 15° 17.19 and the reticle 18 are fixed to the finder frame 11. As is well known, the reticle 18 has a finder field frame, an autofocus target mark, etc. written thereon.

A finder optical axis 6a is provided on the bottom surface of the finder accommodating portion 12.
A thrower 1-21 parallel to the lens frame 20 is formed.
A pin 22 integral with the slot 21 passes through this slot 21.

Further, on the side wall defining the finder housing section 12,
Guide side 24 inclined low toward the objective lens 15 side
are integrally formed. This guide side 24 regulates the vertical position of the lens frame 20 when it moves forward and backward.

That is, as shown in FIG. 2, the side wall of the lens frame 20 has a convex side 25 and a protrusion 26 that vertically sandwich the guide side 24.
are formed, and these five sides 25. The protrusion 26 slides on the guide side 24 to perform a guiding action. A pair of protrusions 27 are also formed on the other side wall of the lens holding frame 20, and a pair of protrusions 27 are formed on the other side wall of the finder accommodating section 12. are sandwiched between the top and bottom.

A mounting root 30 is fixed to the bottom surface of the finder frame 11. In this installation, the finder optical axis 6 is attached to the base 30.
A guide slot 30b perpendicular to a, an arcuate slot 30c, a slot 30 parallel to the finder optical axis 6a
d, a notch 30e is formed. Note that in order to fix the plate 30, a pair of protrusions 30a integrally formed on the plate 30 are inserted into holes formed on the bottom of the finder frame 11; The other end is screwed to the boss 31. The boss 31 protrudes downward, and the protruding piece 3
Since a rising part is formed at the end of 0a,
When mounting, the plate 30 is fixed to the bottom surface of the finder frame 11 with a predetermined gap therebetween.

Between the finder frame 11 and the mounting plate 30,
A cam plate 35 is attached. The cam plate 35 is formed with a cam slot 35a, a long hole 35b, and a protrusion 35c. Then, the protruding piece 35c is attached to the notch 30e of the plate 30.
The cam plate 35 is attached by a pair of caulking pins 36 inserted into the guide slots l-30b of the plate 30, so that the cam plate 35 can be slid laterally with respect to the plate 30. Further, a pin 22 protruding from a slot 21 formed on the bottom surface of the finder frame 11 is engaged with a cam slot 35a.

A fan-shaped gear 41 that rotates around a shaft 40 is rotatably attached to a frame integrated within the camera body 2 . This fan-shaped gear 41 meshes with an interlocking gear 42.

The interlocking gear 42 is connected to the index "T" of the seesaw knob 8 (Fig. 5).
When pressed, the lens is rotated counterclockwise by the motor, and the zoom lens 4 for photographing is adjusted to the telephoto side via the variable power mechanism 43. Also, the finger 41 of the seesaw knob 8
When WJ 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 fan-shaped gear 41. The drive lever 45 engages with a pin 41a fixed to the sector gear 41, and rotates together with the sector gear 41. An interlocking pin 46 is implanted in the drive lever 45. This interlocking pin 46 passes through an arc-shaped slot 30c formed in the mounting Fi 30, and passes through the elongated hole 3 of the cam plate 35.
5b. Since the slot 30c is formed in an arc shape centered on the shaft 40, the drive lever 45
It does not impede the rotation of the.

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

Move the seesaw knob 8 from the neutral position shown in FIG.
When the J side is pressed, the zooming motor starts and the interlocking gear 42 rotates clockwise as shown by the arrow.

When the interlocking gear 42 rotates clockwise, the variable magnification mechanism 43 operates to the wide-angle side, and the zoom lens 4 for photographing
Adjust toward the wide-angle side.

In the process of adjusting the zoom lens 4 to the wide-angle side in this manner, the fan-shaped gear 41 rotates counterclockwise as the interlocking gear 42 rotates clockwise.

As a result, the drive lever 45 also rotates counterclockwise via the pin 41a. When the interlocking pin 46 is displaced counterclockwise at the same time, the cam plate 35 slides to the left through the elongated hole 35b. The sliding of this cam plate 35 is guided by the guide slot 30b, the caulking pin 36, the notch 30e, and the projection piece 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 slide 35a. As a result, the lens frame 20 holding the variable magnification lens 16 is moved from the position shown by the solid line in FIG.

When the lens frame 20 is advanced, the 5 sides of the 25° protrusion 2
6 and the guide side 24, and also the pair of protrusions 27 and the guide side formed on the other side wall of the finder housing 12, the lens frame 20 is moved downward, that is, toward the optical axis 4a of the zoom lens 4. shifted closer together. The amount of shift 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 zoom finder.

FIG. 4 illustrates the above-mentioned effect on the optical system of a zoom finder. FIG. 4 (A) shows the variable magnification lens 16 at the telephoto end, and FIG. indicates a certain condition. By shifting the lens frame 20 downward while moving forward by changing the magnification toward the wide-angle side,
The variable magnification lens 16 moves forward while gradually shifting downward.

At the wide-angle end, the variable power lens 16 is moved down by a shift amount d relative to the telephoto end position.

In this way, when the variable magnification lens 16 is shifted closer to the optical axis 4a in the process of changing the magnification of the zoom finder toward the wide-angle side, the optical axis of the finder is shifted by the drafting action of the variable magnification lens (concave lens) 16. 6a will be deflected upwards. Therefore, at the wide-angle end in FIG. 6(B),
When the principal ray Lo from the center of the photographic screen at a photographing distance of 3 m exits from the eyepiece 19, the exit angle is β8·0 or more. By appropriately setting the shift amount d, this principal ray L0 is shifted to the screen center P at the telephoto end.
, will be able to match.

Furthermore, even at an intermediate viewfinder magnification between the telephoto end and the wide-angle end, by appropriately changing the shift amount of the variable magnification lens 16, the chief ray from the center of the photographic screen can be changed to the telephoto end. It can be made to coincide with the screen center Pt. Therefore, the guide side 24. The shapes of the convex side 25 and the protrusion 26 are determined in consideration of the amount of shift at this intermediate magnification. Of course, if the amount of movement and the amount of shift of the variable magnification lens 16 are non-linear, these sliding contact portions will be formed in a curved shape.

The balarax correction effect due to the shift of the variable magnification lens 16 means that the straight line B is translated in parallel to the position of the straight line B' in FIG. Therefore, the difference between the balarax at the telephoto end (line A) and the corrected balarax at the wide-angle end (line B') can be made small over most of the photographing distance range. In addition, the "shooting distance - balax" straight line in the intermediate magnification range is
Since it intersects straight line A at a point at a photographing distance of 3 m and is expressed as a straight line having an inclination between straight lines A and B, it can be seen that vararax is well corrected for these lines as well.

In the above embodiment, the finder screen center P at the telephoto end is made to match the finder screen center Pw at the wide-angle end, but conversely, the finder screen center P at the telephoto end matches the finder screen center Pw at the wide-angle end. It is also equivalent to match P. Furthermore, according to the present invention, the variation caused by the zoom finder's magnification is corrected simply by shifting the variable magnification lens 16, and no other complicated configuration is required. For example, it is also possible to incorporate a field frame switching mask or the like.

In addition, if you tilt the entire zoom finder, align the finder optical axis of the zoom finder with the center of the shooting screen at a shooting distance of 3m, and set the center of the finder screen on this finder optical axis, the shooting distance of 3m will be maintained regardless of the finder magnification. can eliminate vararax. However, even with this configuration, at shooting distances other than 3 m, the center of the shooting screen at each drawing distance position will deviate from the center of the set finder screen, and the amount of deviation will still depend on the viewfinder screen center. It corresponds to the magnification. Therefore, the present invention, which suppresses the amount of deviation by the deflection action of the variable magnification lens, can be similarly applied to a zoom finder having such a configuration.

(Effects of the Invention) As explained above, according to the zoom finder device of the present invention, the variable magnification lens that is moved when changing the finder magnification is not only moved in the direction of the finder optical axis ( Parallax that occurs when the viewfinder magnification is changed is corrected by shifting it along the axis.Therefore, the subject image does not move excessively within the viewfinder field of view while the viewfinder magnification is changed. , framing operations, or focusing operations using the distance measurement area displayed in the viewfinder become easier.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of essential parts showing an 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. 1. FIGS. 4(A) and 4(B) are explanatory diagrams showing states in which the optical system of the apparatus of the present invention is set to 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 a conventional zoom finder is set at the telephoto end and wide-angle end, respectively. FIG. 7 is a graph showing the correlation between shooting distance and 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. to ri

Claims (1)

[Claims] (1) a variable magnification lens movably provided between the finder objective lens and the eyepiece; a movement mechanism for moving the variable magnification lens forward and backward along the finder optical axis in conjunction with zooming of the photographic lens; A zoom finder device comprising: a shift mechanism that shifts the optical axis of the variable magnification lens toward or away from the optical axis of the photographic lens when the variable magnification lens moves forward or backward.