JPH0248617A - Lens barrel for close-up photographing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lens barrel that is attached to an intermediate device for close-up photography and used when photographing a subject in close-up or enlarged form using a camera.

(Prior art) Conventionally, when performing so-called close-up photography at magnifications ranging from 0.2x to around 10x, an intermediate device has been used to widen the distance between the camera and the photographic lens (lens barrel). It is being Generally, the intermediate device used is a bellows-type feeding device that telescopically connects the camera mounting part and the photographic lens mounting part with a light-shielding bellows, or a so-called intermediate tube that is interposed between the camera and the photographic lens. has been done. The photographic magnification is determined by the amount of extension of the photographic lens, so in the case of the former bellows type, by adjusting the amount of expansion and contraction of the bellows, and in the case of the latter tube, by changing the tube length, the desired photographic magnification can be achieved. was obtained, and filming is underway.

FIGS. 4(a), 4(b), and 4(C) are correlation model diagrams between the green exposure amount d of the photographing lens and the photographing magnification β.

L is the photographing lens with focal length f, F is the film plane as the imaging plane, Yo is the subject, Y is the image formed, and a is the subject distance (
4-4 Subject Y on the photographic lens. The open circuit a>, b is the image distance (
Distance a> between the photographing lens LH and the imaging plane F, X is the photographing distance (subject Y. H imaging plane F open path 1 m).

(a) In the figure, the distance of the photographic lens L is d = 0, that is, the focal point of the lens L is located on the imaging plane F, and the photographing magnification β = 1/(
Case 1) is shown. Figures (b) and (C) each show the state in which the lens L is used, and the photographing magnification β is approximately 1x in Figure (b), and 2x in Figure (C).

The imaging magnification β, the imaging distance, and the subject pressure 1Ila are each expressed by the following relational expressions.

β=Y/Yo =b/a=d/f j l @ (t
)11,=f (1+β)2/β... (2)
The graph in Figure 1 is a solution of (2) above with the shooting distance llI/, as a constant value, and the lens length is 1/I/. If the focal length f of the W & shadow lens is changed from increasing to decreasing in conjunction with the increase in d (the increase in the open circuit layer between the photographing lens and the film (focal plane) when the photographing magnification is 110o), the photographing distance 2 will be It is possible to monotonically increase the imaging magnification β without changing it.

(Problems to be Solved by the Invention) By the way, one important matter for realizing a reliable close-up photography device that follows the principle of variable magnification as described in -h is the provision of intermediate devices and lens barrels (variable magnification lenses, These include the accuracy of the initial setting of the interlocking members on both sides when mutually mounted with a variable focal length photographing lens, and the elimination of mechanical backlash and so-called "play" during operation.

The present invention provides a lens barrel for close-up photography that does not have this problem.

(Means for Solving the Problems) The present invention is a lens barrel for close-up photography that is attached to a retractable intermediate device of a close-up photography device, and includes two or more groups that move in the optical axis direction for variable magnification photography. a variable power lens group; a cam mechanism that operates in conjunction with the expansion/contraction operation of the intermediate device to move the variable power lens group to a variable power position according to the amount of expansion/contraction of the intermediate device; A lens barrel for close-up photography characterized by having means for biasing a movable member in one direction.

(Function) Figure 2 shows variable focal length photographing lens A as a lens barrel.
It is an optical system model diagram of an example of L.

L2, L3, and L4 are lens groups each composed of one or more lenses, and D is an aperture. By moving the lens group L1, the second lens group L2, the third lens group L3, the fourth lens group L4, and the diaphragm D, the focal length is changed, that is, the magnification is changed.

The lens position states in (a), (b), and (C) in Figure 2 are the focal length a1 f rf on the graph in Figure 1, respectively.
It shows the position state when . (a) and (() have an optically conjugate arrangement, f,=t3.1/β1=
Due to the relationship 1/β3, β,=x1. In other words, the second
The lens group L2, the third lens group L3, and the aperture D move linearly together. 4th lens group L1 and 4th lens group L4
moves completely symmetrically with respect to the second lens group L2, the third lens group L3, and the aperture p, and the distance between the lenses is the closest in the low magnification state (Fig. 2 (a)). group and the second lens group L2/third of the fourth lens group
The movements on the optical axis relative to the lens group L3 and the aperture D are movements from photographing magnification β1 to β2 (same magnification) and β3.
The structure is such that the movement from β2 (equal magnification) to β2 (equal magnification) is equal. That is, the positions of the second lens group L2, the third lens group L3, and the aperture D for each magnification of the second lens group 3 and the fourth lens group L4 are as shown in FIG. Also, at each magnification and any shooting magnification in between,
The distance between the subject and the intended image plane is always constant, and once focused, there is no need to focus again even if the magnification is changed.

When the lens barrel as described above is attached to the intermediate device, the cam mechanism causes the variable power lens group of the lens barrel to change the magnification according to the amount of expansion and contraction of the intermediate device in conjunction with the expansion and contraction operation of the intermediate device. By moving the cam mechanism to the desired position and constantly biasing it in one direction using the movable biasing means of the cam mechanism, the initial settings of the interlocking members on both sides when the intermediate device and lens barrel are attached can be adjusted. Accuracy is ensured, and mechanical backlash and "play" during operation can be eliminated.

(Example) Fig. 5 is a longitudinal sectional side view of a close-up photographing device equipped with a lens barrel according to the present invention, and A is a general symbol of a variable focal length photographing lens (hereinafter abbreviated as photographing lens) as a lens barrel. , B is the general code of the intermediate device (bellows), and C is the camera. Regarding camera C, its outline is indicated by a two-dot chain line and the detailed structure is omitted.

■, Configuration of shooting lens A, vertical sectional side view in Figure 5, developed plan view of main parts in Figure 6, Figure 7
In the plan view shown in the figure and the side view shown in Fig. 8, 1 is an exterior ring;
3 is a guide cylinder which is fitted concentrically into this exterior ring with an annular gap and is integrally screwed together with the exterior ring; 3 is a front group cam cylinder which is fitted concentrically into this guide cylinder; It can be freely rotated forward and backward around the optical axis inside. 4 is the guide tube 2
A fixed lens barrel is integrally screwed concentrically with the guide barrel at the rear end and protrudes rearward from the rear end of the exterior ring 1, and reference numeral 5 denotes a rear group externally fitted concentrically to the fixed lens barrel. It is a cam barrel that can freely rotate forward and backward around the optical axis on the outside of the fixed lens barrel.

Reference numeral 6 designates an annular mount that is integrally attached and fixed to the distal end flange portion of the fixed lens barrel 4 at the rear end position of the exterior ring 1, and is for attachment to an intermediate device B, which will be described later. Therefore, the four members, the outer ring 1, the guide tube 2, the fixed lens barrel 4, and the mount 6, are integral with each other.

Reference numeral 7 denotes a lens barrel holding the lens group L1, which is fitted inside the front group cam barrel 3 at the tip end side thereof and concentrically with the cam barrel. Reference numeral 8 denotes a second lens group barrel holding the second lens group L2, which is integrally mounted and supported at the tip of the fixed lens barrel 4, and the cam 'f4 is mounted on the rear end side of the front group cam barrel 3.
3, and is located concentrically with the cam cylinder.

Reference numeral 9 denotes a third lens group barrel which is integrally molded within the fixed lens barrel on the distal end side of the fixed lens barrel 4, concentrically with the lens barrel, and holds the third lens group 3. are doing. 10
A fourth lens group lens barrel is fitted inside the rear end side of the fixed lens barrel 4, and holds the fourth lens group L4. 11 is the second
and an aperture unit that is integrally mounted and supported on the fixed lens barrel 4 side in the open position with the third lens group barrels 8 and 9, and includes a stepping motor lla.
The aperture D is driven by 1a.

The cylindrical surface of the guide tube 2 has two stripes parallel to the optical axis (in the direction of the generatrix of the cylindrical surface) at two locations on the cylindrical circumference facing each other by approximately 180 degrees, as shown in the developed plan view of the main part in Fig. 6. It is provided with straight groove holes 12 and 12, and first and second two parallel circumferential groove holes 13 and 14 in the cylinder circumferential direction, which is a direction perpendicular to the straight grooves. Further, the cylindrical surface of the front group cam cylinder 3 fitted inside the guide cylinder 2 has a diameter of about 180° around the cylindrical circumference.
Edge calcam grooves 15 are provided at two opposing positions. The lens barrel 7 of the lens group fitted inside the front group cam barrel 3 is provided with a pin shaft 16 at two positions approximately 180° opposite to each other around the barrel circumference.
16, and their respective bottle shafts are connected to the front group cam cylinder 3.
The edge calcam slot 15 and the straight slot 12 of the guide tube 2
The intersecting portions of both are penetrated and engaged. Therefore, the first lens group lens barrel 7, that is, the first lens group L1 moves forward in the optical axis direction within the front group cam barrel 3 by rotating the front group cam barrel 3 forward and backward around the optical axis with respect to the guide barrel 2. Move backwards. 1
Reference numeral 7 denotes a front group biasing spring that is stretched between the tip of the exterior ring 1 and the lens group barrel 7, and constantly pulls the lens barrel 7 in the forward group in the front group cam barrel 3. It is energizing.

Reference numeral 18 denotes a protruding member integrally provided on the outer surface of the front group cam cylinder 3, the tip of which is connected to the guide cylinder 2. (7) First circumferential groove hole! 3 is passed through and protrudes toward the outer surface of the guide tube 2. Reference numeral 19 denotes a bottle installed on the outer surface of the guide tube 2, and a cam tube drive spring 20 is installed between the bottle 19 and the projection member 18.
is set up. This cam barrel drive spring 20 is connected to the front group cam barrel 3 when viewing the photographic lens A from the front (the side of the lens group L1).
is constantly urged to rotate clockwise (forward direction) around the optical axis within the guide tube 2.

On the other hand, on the cylinder surface of the fixed lens barrel 4, as shown in the developed plan view of the main part in FIG. Linear straight grooves 21 and 21
It is equipped with. Further, the cylindrical surface of the rear group cam cylinder 5 fitted onto the fixed lens barrel 4 is provided with edge cam grooves 22 at two positions approximately 180° opposite to each other around the cylinder periphery. Then, the fourth lens group barrel 10, which is fitted inside the fixed barrel 4, has a cylinder circumference of approximately 180 mm.
Bottle shafts 23, 23 are installed at two opposing positions, and these bottle axes are inserted into the intersections of the straight slot 21 of the fixed lens barrel 4 and the edge cam slot 22 of the rear group cam barrel 5, respectively. The part is penetrated and engaged.

Therefore, the fourth lens group barrel 10, that is, the fourth lens group L4,
By rotating the rear group cam barrel 5 forward and backward around the optical axis with respect to the fixed lens barrel 4, it moves backward and forward in the optical axis direction within the fixed lens barrel 4. 24 is a rear group biasing spring stretched between the rear end of the fixed lens barrel 4 and the fourth lens group barrel 10; is constantly under tension.

A key member 25 has one end fixed to the outer surface of the front end side of the rear group cam cylinder 5 and the other end fitted into a notch groove 26 formed in the rear end flange of the front group cam cylinder 3. Therefore, rotational force is transmitted between the rear group cam cylinder 5 and the front group cam cylinder 3 through this key member 25, and when one rotates in the forward and reverse directions, the other also rotates in the forward and reverse directions.

Reference numeral 27 denotes an interlocking pawl that is integrally provided on the outer surface of the rear group cam cylinder 5 and is interlocked with an intermediate device B, which will be described later.

Reference numeral 28 denotes an electric signal bin assembly provided on the mounting mount 6.

A circuit unit 29 is fixed to the outer surface of the guide tube in a gap space between the outer ring 1 and the guide tube 2, and is connected to the aperture unit 11 and the electric signal bin assembly 28 via lead wires (not shown). are connected to each other.

30 is housed in the gap space between the outer ring 1 and the guide tube 2,
It is a magnification display plate in the shape of an arc plate concentric with the optical axis, and a downwardly bent leg portion 30a integral with the display plate is passed through the second circumferential groove hole 14 of the guide tube 2 and fitted into the guide tube 2. It is supported by the front group cam cylinder 3 by being integrally fixed to the outer surface of the front group cam cylinder 3. Therefore, when the front group cam barrel 3 is rotated in the forward and reverse directions, the magnification display plate 30 rotates in the forward and reverse directions around the optical axis together with the cam barrel.

31 is a window hole provided on the outer surface of the exterior ring 1; 31a is a transparent cover member for dustproofing that covers this window hole; is visible.

Reference numeral 32 (FIGS. 7 and 8) is a fixed index attached to the outer surface of the rear end side of the exterior ring 1, and is an alignment mark when attaching the photographing lens A to an intermediate device B, which will be described later.

1st to 4th lens groups, -L4. and the aperture D is the second
It corresponds to the first to fourth lens groups L1 to L4 and diaphragm D in Fig. and a second lens group L2 and a third lens group in which the lens group lens barrel 7, that is, the lens group 1, and the fourth lens group lens barrel 10, that is, the fourth lens group L4 are respectively immovable along the optical axis. move away from L3 (the 4th lens group L1 moves forward along the optical axis, the 4th lens group L1 moves forward along the optical axis,
On the contrary, the lens group L4 moves backward), or the second lens group L2
・The lens group moves in the direction approaching the third lens group L3 (the third lens group moves backward along the optical axis, and the fourth lens group L4 moves forward), and the lens group arrangement becomes as shown in Figure 2 (a). )・(C), Fig. 3(a) Array in the short focus state of (C) (magnification β1
or arrangement state of β3), or Fig. 2(b) and Fig. 3(b
) in a long focus state (array state with magnification β2 (same magnification)).

On the right side of the vertical side view of the device in FIG.
The upper half from the optical axis with -0 as the border shows the mutual arrangement in the short focus state with magnification β1 or β3, and the lower half shows the magnification β2 (same magnification).
The mutual arrangement of the two images in the long focus state is shown.

■ Structure of Intermediate Device B In the longitudinal sectional side view of FIG. 5, the side view of FIG. 9, and the partially cutaway front view of FIG. A rack 51 is fixedly provided along the support member (hereinafter referred to as the first support member) for mounting the photographic lens.
(referred to as a support member), and is mounted on the guide rail member 50 so that the base side engages with the rail member in a dovetail groove so that it can smoothly and stably slide forward and backward along the length of the rail member. It is. Reference numeral 52 denotes a support member (hereinafter referred to as a second support member) for mounting the camera, and the first support member 5
1, and is mounted on the guide rail member 50, with the base side engaged with the rail member in a dovetail groove, so that it can smoothly and stably slide forward and backward along the length of the rail member. It is.

Reference numeral 53 denotes a drive knob shaft disposed on the base side of the first support member 51 so as to pass through the member in the left-right direction and be freely rotatably supported;
54, 54 are knobs fixed to both left and right ends of the knob shaft;
Reference numerals 5 and 56 indicate a drive gear and a drive gear, which are respectively fixed to the middle of the knob shaft. Therefore, when the knob 54 is rotated in the forward and reverse directions, the pinion gear 55 and the rack 50a on the guide rail member 50 side are engaged with each other, so that the first member 51
slides forward and backward along the rail member 50.

Similarly, regarding the second support member 52, a drive knob shaft 57 is disposed through the base side of the second support member 52 so as to be freely rotatably supported, and a drive knob shaft 57 is disposed in the middle thereof to be engaged with the rack 50a on the guide rail member 50 side. Matching pinion gears 59 are provided, and the second member 52 is slid forward and backward along the rail member 50 by rotating knobs 58 fixed to both left and right ends of the knob shaft 57 in forward and reverse directions.

In the first member 51, 60 (Fig. 10) is an opening for inserting a photographic lens, 61 is an annular mount fixed concentrically with the opening 60 on the front side of the member 51, and 62 and 63 (Fig. 5) are the members. A pair of front and rear interlocking rings 64 are rotatably assembled concentrically with the opening 60 on the right side of the back side of the member 51, and 64 are the first and second interlocking ring receivers, which are fixed to the member 51. and the first and second interlocking rings 62 and 6
3 is rotatably held. 62a and 63a are first and second interlocking claws provided inwardly on a part of the inner periphery of the first and second interlocking rings 62 and 63, and 62b and 63b are the first and second interlocking claws, respectively. These are first and second annular interlocking gears that are integrally provided on each side of the interlocking rings 62 and 63 so as to be concentric with the rings. A drive gear 5 integrated with the drive knob shaft 53
6 and the second interlocking gear 63b are connected to the interlocking gear train 0.
We will contact you via 1 to G7. Gears G1 and G2, G3 and G4, and G5 and G6 are coaxial, integrally rotating two-stage gears. Also, the final gear G7 of the above gear train (
The second interlocking gear 63b and the first interlocking gear 62b are engaged with each other via a differential gear G8 (FIG. 10).

Therefore, as described above, the photographing lens is attached when the first support member 51, which is a support member, is slid forward and backward along the guide rail member 50 by rotating the knob 54 in the forward and reverse directions. The forward or reverse rotational force of the drive gear 56 is transmitted to the second interlocking gear 63b via the gear trains 01 to G7, and further transmitted to the first interlocking gear 62b via the differential gear G8. The first and second interlocking rings 62 and 63 are driven in forward and reverse directions with the same rotation angle but opposite rotation directions.

Reference numeral 65 (FIG. 5) is an electric signal bottle assembly in which the tip of the bottle is always urged to protrude by an elastic spring plate member 65a on a part of the outer surface of the annular mount 61, and the first member 5
When the photographing lens A is properly attached to the photographing lens mounting opening 60 of No. 1, the electric signal assembly 28 on the photographing lens A side faces the electric signal assembly 65, and both assemblies 65 and 28 The corresponding bottles are pressed into contact with each other, and both assemblies 65 and 28 are in electrical communication with each other.

Reference numeral 66 (FIG. 10) is a fixed index attached to the outer surface of the uppermost portion of the annular mount 61, and is a mark for alignment with the fixed index 32 (FIGS. 7 and 8) attached to the photographing lens A side.

The camera is attached to the second support member 52 as a support member, with reference numeral 67 an opening for attaching the camera, and reference numeral 68 an annular mount for attaching the camera fixed concentrically with the opening 67 on the back side of the member 52.

69 is interposed between the first support member 51 and the second member 52, with the front end fixed to the first support member 51 and the rear end fixed to the second support member 52. It is a bellows serving as a dark housing part with a telescopic structure in which the photographing lens fitting opening 60 on the side and the camera mounting opening 67 on the second support member 52 side are communicated in the optical axis direction.

Reference numeral 70 denotes an electrical signal bin assembly mounted on the annular mount 68 for mounting the camera.

By engaging a facing mount (not shown) on the camera C side with the mount 68, the camera C is firmly mounted and supported on the second support member 52.

When the camera C is properly mounted and supported on the second support member 52 via the mount 68, the mount 68
An electrical signal bin assembly (not shown) on the camera C side comes into corresponding contact with the electrical signal bin assembly 70 on the side, and the two assemblies are in electrical communication with each other.

Electricity No. 43 bottle assembly 7 on the second support member 52 side
0 and the same assembly 65 on the side of the first support member 51 are electrically connected by a lead wire (not shown). Therefore, the photographic lens A is attached to the first support member 51 of the intermediate device B, and the second
When the cameras C are properly mounted and supported on the support members 52, the electric circuit on the camera C side and the electric circuit on the photographic lens A side are in communication with each other.

The bellows 69 moves the first support member 51 and/or the second support member 52 forward and backward along the guide rail member 50 by forward and reverse rotation operations of the knobs 54 and 58, thereby increasing and decreasing the mutual spacing between the members 51 and 52. When changed, the aperture 60 for fitting the photographing lens on the first support member 51 side and the aperture 67 for attaching the camera on the second support member 52 side expand and contract depending on the size of the mutual spacing, and the aperture 67 for attaching the camera on the second support member 52 side extends and contracts in accordance with the size of the mutual interval. We are always in contact with each other on the road.

(2) Interlocking of intermediate device B and photographic lens A. The photographic lens of intermediate device B (hereinafter referred to as Rose) is attached to the first support member 51, which is a support member. The photographic lens A is attached to the first support member 51. Insert the rear group cam cylinder 5 portion of the photographing lens A into the fitting opening 60 so that the fixed index 32 on the photographing lens A side corresponds to the fixed index 66 on the first support member 5'1 side. Adjust the rotation angle posture of the photographic lens A, and move the mount 6 on the photographic lens A side to the first position.
It is brought into contact with the mount 61 on the support member 51 side, and the photographing lens A is sufficiently rotated clockwise until further rotation is prevented by a stopper portion (not shown). (A rotation operation of approximately 60° in the present embodiment) As a result, the photographing lens A is stably mounted and supported on the first support member 51 by the mutual engagement of the mounts 6 and 61. In the normal mounting state, the photographing lens A is in a rotating angle position in which the magnification display window 31 portion of the outer ring 1 faces upward, and the electric signal bin assembly 28 is normally attached to the same assembly 65 on the first support member 51 side. They face each other face-to-face and are electrically connected to each other.

When the photographing lens A is inserted into the opening 60 of the first support member 51 and rotated in the same manner as shown above in order to attach the photographing lens to the first support member 51, the rear group cam of the photographic lens A is rotated. The interlocking pawl 27 protruding from the outer surface of the cylinder 5 is the first
The second interlocking pawl 63a on the support member 51 side comes into contact with and is locked. For this purpose, the rotation of the rear group cam cylinder 5 and the front group cam cylinder 3, which is integrated with this cam cylinder through the key member 25, is stopped at that point, but the exterior ring 1 is integrally screwed together with the rear group cam cylinder 5. The guide cylinder 2 is fixed to the guide cylinder with screws. The cylinder 4 and the mount 6, which is fixedly attached to the body at the distal end flange of the fixed m cylinder, rotate further until further rotation is prevented by a stopper part (not shown). As a result, the cam cylinder drive spring 20 is stretched between the protruding member 18 of the front group cam cylinder 3 and the planting pin 19 of the guide cylinder 2.
becomes stretched. The developed plan view of the main part of FIG. 6 shows the spring 20 in a stretched state. In other words, the photographing lens A is attached to the first support member 5 of the bellows B.
After attaching to 1, the spring 20 is stretched as shown above.
Due to the reaction force, the interlocking claw 27 of the rear group cam barrel 5 of the photographing lens A
is always pressed and kept in contact with the second interlocking pawl 63a on the first support member 51 side without play.

With the photographic lens A attached to the first support member 51 of the bellows B as described above, and the camera C attached to the second support member 52, the first support member 51 and the knob 54 are rotated in the forward and reverse directions. When the guide rail member 50 is moved forward and backward, the forward and reverse rotation forces of the drive gear 56 are transmitted to the second interlocking gear 6 via gear trains 01 to G7.
3b and has a second interlocking pawl 63a.
The interlocking ring 63 is rotated forward and backward. The interlocking gear 62b of the writer 1 rotates in the normal direction via the gear G7 and the differential gear G8.
The first interlocking ring 62 receives a reversing force and is rotated forward and reverse in a relationship such that the rotation angle is equal to that of the second interlocking gear 63b but the rotation direction is opposite, and the first interlocking ring 62 has a first interlocking pawl 62a.
is rotated forward and reverse. That is, a second interlocking ring 63 having a second interlocking pawl 63a, and a first interlocking pawl 62a.
The first interlocking ring 62 having a
In conjunction with the forward and backward movement operations along the guide rail member 50, the motor rotates forward and backward in the above relationship.

And the second interlocking claw 63a of the second interlocking ring 63
, or the first interlocking claw 62a of the first interlocking ring 62, the interlocking claw 27 on the photographing lens A side is always in engagement contact with the reaction force of the spring 20 in the above-mentioned stretched state,
Therefore, the second or first interlocking ring 6 is interlocked with the forward/backward movement operation of the first support member 51 along the guide rail member 50.
In conjunction with the forward and reverse rotations of lenses 3 and 62, the rear group cam barrel 5 of the photographing lens A is rotated in the forward and reverse directions around the outside of the fixed lens barrel 4. Also, the front group cam cylinder 3, which is integrated with the rear group cam cylinder 5 via the key member 25, is connected to the guide cylinder 2 together with the rear group cam cylinder 5.
Rotates forward and reverse inwardly. In conjunction with the forward and reverse rotation of the front group and rear group cam barrels 3 and 5, as described above, the lens group lens barrel 7, that is, the lens group Ll, and the fourth lens group lens barrel 10, that is, the fourth lens. The lens group L4 is driven to move away from or toward the second lens group L2, the aperture D, and the third lens group L3, which are stationary, respectively, along the optical axis, and as shown in FIGS. Figure 3 (a) Lens array in short focus state (C) (array state with magnification β1 or β3)
, or changes steplessly to the long focal state lens arrangement (magnification β2 (equal magnification)) shown in FIGS. 2(b) and 3(b).

■Specifically, when changing the magnification from the low magnification side (photographing magnification β) to the high magnification side β1 → β2 → β3 in FIG. It is rotated in the normal direction to move forward along the guide rail member 50.

In the low magnification state where the first support member 51 is closest to the second support member 52 located on the rear end side of the guide rail member 50 as shown in FIG.
The interlocking mechanism is the interlocking pawl 2 on the lens A side as shown in Figure 11.
7 and the second interlocking pawl 63a on the bellows portion side are in contact with each other.

■ From this state, rotate the knob 54 in the forward direction to move the first support member 51 of the bellows B forward to the approximately midpoint position of the rail member 50 as shown by the two-dot chain line in FIG. It is designed to be β2. At this time, the interlocking mechanism between the lens A and the bellows B is as shown in FIG. (cannot be seen because it overlaps with) are in contact with each other.

■Furthermore, rotate the knob 54 in the normal direction to move the first support member 51 of the bellows B to the rail member 5 as shown by the three-dot chain line in FIG.
If you move it forward to a position closer to the tip of 0, the imaging magnification will be
From the same magnification β2 to the higher magnification β3, at this time the interlocking mechanism between lens A and bellows B becomes as shown in Fig. 13.
The interlocking claw 27 on the lens A side is in contact with the first interlocking claw 62a on the bellows side.

By the above operation ■→■→■, the rear group cam 85 of photographing lens A is
And the front group cam cylinder 3 is connected to the interlocking rings 63 and 62 of the bellows B.
With the movement of , from low magnification β1 to equal magnification β2, equal magnification β,
The direction of rotation is reversed from to high magnification β3. The movements of each lens group ~L4 and diaphragm D are shown in FIG. Further, the movements of each lens group L1-L4 and the lens group D with respect to the planned image forming plane F (film plane in the camera C) are as shown in FIG.

Furthermore, a front group biasing spring 17 is installed between the first lens group lens barrel 7 and the tip of the exterior ring 1, and a front group biasing spring 17 is installed between the first lens group lens barrel 7 and the tip of the outer ring 1.
The urging force assists the movement of the pin shaft 16 passing through the edge cam slot 15 of the front group cam cylinder 3 in the direction of extension of the spring 17. At the same time, since the position of the bottle shaft 16 relative to the hemlock cam slot 15 is pressed in one direction by the urging force, the positional accuracy of the bottle shaft 16 can be determined with high precision.

Further, a rear group biasing spring 24 is installed between the fourth lens group barrel 10 and the end of the fixed lens barrel 4, and biases the fourth lens group barrel 10 in the extension direction. The spring 24 of the pin shaft 23 fitted into the edge cam slot 22 of the rear group cam cylinder 5
It helps the movement in the elongation direction. At the same time, since the position of the bottle shaft 23 relative to the edge cam slot 22 is pressed in one direction by the urging force, the positional accuracy of the bottle shaft 23 can be determined with high precision.

The magnification display plate 30 rotates together with the cam barrel 3 as the front group cam barrel 3 rotates in the forward and reverse directions to change the magnification by rotating the knob 54 in the forward and reverse directions. Guide rail member 5 of the first support member 51 on the moved bellows 8 side
The magnification value display part corresponding to the current position on 0 is located in the upward window hole 31 provided on the outer surface of the outer ring 1, and the magnification value at the current time corresponds to the index 31b (FIG. 7). $ is displayed accurately.

Thus, the photographing lens (lens barrel) A of this embodiment has a cam mechanism that moves the variable magnification lens group -L4, and the cam barrels 3 and 5 as movable members of the cam mechanism are biased by the spring member. 20, so that the interlocking members on both sides of the photographic lens and the bellows (intermediate device) on which the lens is attached are always elastically abutted and engaged. When attaching the photographing lens A to the camera, accurate initial settings of the interlocking members on the B-A side became possible.

■It is now possible to mechanically eliminate backlash and play in the interlocking member between bellows B and photographic lens A.

(Effects of the Invention) As explained above, by providing a mechanism for biasing the movable member of the cam means for moving the variable magnification lens group of the lens barrel in one direction in conjunction with the expansion and contraction of the intermediate device, It has become possible to ensure the accuracy of the initial settings of interlocking members on both sides when the intermediate mounting device and lens barrel are mutually mounted, and to eliminate mechanical backlash and "play" during operation.

[Brief explanation of the drawing]

Figure 1 is a principle mode graph for close-up photography, Figures 2 and 3 are optical system model diagrams of variable focal length photography lenses, and Figure 4
Figures (a), (b), and (c) are model diagrams of the correlation between the amount of lens extension and photographic magnification, Figure 5 is a vertical cross-sectional side view of a close-up photographing device equipped with a lens barrel according to the present invention, and Figure 6 is a diagram of the lens barrel. Figures 7 and 8 are a plan view and side view of the photographing lens, Figure 9 is a side view of the intermediate device (bellows), and Figure 10 is a partially cutaway front view. , Fig. 11, Fig. 12, and Fig. 13 respectively show the interlocking claw on the photographing lens side,
FIG. 7 is an explanatory diagram of the engagement relationship with the interlocking pawl on the intermediate device side. A is the photographic lens (focal length variable photographic lens), B is the intermediate device (bellows), C is the camera, L, ~L4 are the first to fourth lens groups, D is the diaphragm, and 5152 is the intermediate device's photographic lens installation. 5 is a supporting member (first supporting member), a supporting member (second supporting member) for mounting the camera, 50 is a guide rail member, and 5 is a supporting member (first supporting member).
4.58 is a support member movement operation knob.

Claims (1)

[Claims] (1) A lens barrel for close-up photography that is attached to a telescoping intermediate device of a close-up photography device, comprising two or more variable magnification lens groups that move in the optical axis direction for variable magnification photography, and the intermediate device. a cam mechanism that operates in conjunction with the expansion/contraction operation of the intermediate device to move the variable magnification lens group to a variable magnification position corresponding to the amount of expansion/contraction of the intermediate device; and means for biasing the movable member of the cam mechanism in one direction. A lens barrel for close-up photography, comprising: