JPH10111444A - Camera lens barrel frame with variable diaphragm mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera, lens barrel frame with a variable diaphragm mechanism by which the gap between a lens and a member interposing variable diaphragm blades can be more shortened by contriving the arrangement of the variable diaphragm blades. SOLUTION: This lens barrel frame is arranged in a photographing lens optical system and provided with the variable diaphragm blades 4A and 4B whose aperture diameter can be changed so as to regulate the transmitted luminous flux of light used for exposure and the lens 5 which is arranged by being adjacent to the blades 4A and 4B and at least whose surface faced to the blades 4A and 4B is convex. In such a case, the positions of the actuation surfaces of the blades 4A and 4B in an optical axis direction are arranged at a position where they enter the lens surface side from the top of the convex surface of the lens 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens frame with a variable diaphragm mechanism capable of changing the size of a light beam passing through a photographic lens optical system of a camera.

[0002]

2. Description of the Related Art Generally, in a lens shutter camera, a shutter blade, which is a first sector for opening and closing an exposure aperture for performing exposure control, and a second aperture diameter for varying the size of a light beam passing therethrough are varied. There is known a configuration in which a variable aperture blade as a sector is provided in a taking lens optical system. In this case, the shutter blades are always fully opened, the size of the passing light flux is determined based on the aperture of the variable aperture blade according to the set aperture value, and the exposure amount is controlled by combining these two.

[0003] A shutter, which is composed of a shutter blade that also serves as an aperture blade, controls the exposure amount in combination with the opening diameter and the opening / closing speed, and separately from this shutter, the maximum luminous flux diameter according to the variable focal length of the taking lens. Some lens shutter cameras have aperture blades for changing the maximum aperture diameter. A variable aperture mechanism of this type of conventional camera will be described with reference to a cross-sectional view of a main part of a taking lens barrel shown in FIG. 7. A front lens 105 is fixed to a lens frame 101, and behind the front lens 5. Shutter holding member 102
Is fixed to the lens frame 101. Shutter blades 103A and 103B are rotatably supported by support shafts 102a and 102b, respectively, on the shutter holding member 102, and further behind the shutter blades 103A and 103B are used for changing the aperture diameter of the aperture for determining the aperture light beam or the maximum. Variable aperture blades 104A, 10 for changing the beam diameter to regulate the maximum aperture diameter
4B is rotatably supported by the support shafts 102c and 102d. Although not shown, a rear lens is fixed to the lens frame 101 behind the shutter holding member 102. Here, as shown in FIG. 7, the shutter blades 103A, 103
B and the variable aperture blades 104A and 104B are arranged such that the blade operating surfaces perpendicular to the optical axis do not overlap with the front lens 105 in the optical axis direction.

[0004]

However, in such an arrangement, the shutter blades 103A, 103A,
3B and the thickness in the optical axis direction occupied by the variable aperture blades 104A and 104B, and the distance L 'between the front lens 105 and the rear lens (not shown) or the shutter holding member 102 is to be increased. As described above, there has been a problem that it is impossible to make the lens barrel compact by reducing the distance between the two lenses and to increase the degree of freedom in lens design.

[0005] In view of such problems, an object of the present invention is to provide:
It is an object of the present invention to provide a lens frame with a variable aperture mechanism for a camera, in which the arrangement of the variable aperture blades is devised so that the distance between lenses and members sandwiching the variable aperture blades can be further reduced.

[0006]

In order to solve the above-mentioned problems, in a lens barrel with a variable aperture mechanism of a camera according to the present invention, a photographic lens optical system and a photographic lens optical system provided in the photographic lens optical system for exposing. A variable aperture blade whose aperture diameter can be changed so as to regulate the light beam passing therethrough, and which constitutes a part of the photographing optical system, is disposed adjacent to the aperture blade, and at least a surface facing the aperture blade is convex. Wherein the working surface of the diaphragm blade in the direction of the optical axis is disposed at a position that is closer to the lens surface than the convex top of the lens.

In the lens frame with a variable aperture mechanism of the camera according to the present invention, a photographic lens optical system and an aperture diameter which is provided in the photographic lens optical system and which changes the aperture diameter so as to regulate the passing light flux of light to be exposed. A possible variable aperture blade, a lens that constitutes a part of the photographing optical system, is disposed adjacent to the aperture blade, and has a convex surface at least on the surface facing the aperture blade, and moves the lens in the optical axis direction. A lens driving mechanism for moving back and forth, wherein the position of the working surface of the diaphragm blade in the optical axis direction is, when the lens is closest to the diaphragm blade by the lens driving mechanism, from the top of the convex surface of the lens. Are also arranged at positions where they enter the lens surface side.

Further, in the lens frame with the variable aperture mechanism of the camera according to the present invention, the aperture diameter is changed so as to regulate the passing light flux of the light to be exposed, which is provided in the taking lens optical system and the taking lens optical system. A possible variable aperture blade, an aperture blade opening / closing mechanism for driving the aperture blade to open and close, and a part of the imaging optical system, which is disposed adjacent to the aperture blade and has at least a surface facing the aperture blade. A lens having a convex surface, and a lens driving mechanism for moving the lens back and forth in the optical axis direction, wherein the position of the working surface of the diaphragm blade in the optical axis direction is such that the lens is moved to the diaphragm blade by the lens driving mechanism. When approached most, it is arranged at a position that enters the lens surface side from the convex surface top of the lens,
The aperture blade is in a substantially open state with an opening diameter, and when the lens moves in a direction away from the aperture blade by the lens driving mechanism, the aperture blade is driven by the aperture blade driving mechanism in a direction to reduce the opening diameter. It is characterized by.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to illustrated examples. FIG. 1 is an exploded perspective view showing a main part of a lens frame with a variable aperture mechanism of a camera according to a first embodiment of the present invention. FIGS. 2 and 3 show the embodiment of the present invention. FIG. 2 is a sectional view of a main part of a lens frame with a variable aperture mechanism of the camera shown in FIG.
FIG. 3 shows a state where the aperture of 4B is the smallest, and FIG. 3 shows a state where the apertures of the variable aperture blades 4A and 4B are the most open.

The lens barrel 1 is a cylindrical member, and has a front lens 5 fixed to the distal end thereof, and a shutter holding member 2 fixed to the rear of the front lens. A rear group frame member (not shown) having a rear lens (not shown) fixed to a frame member (not shown) is disposed behind the shutter holding member 2, and is coaxial with the lens frame 1. The focal length can be changed by making the distance between the front lens 5 and the rear lens variable so as to be movable. As described above, the lens barrel of the present camera includes the first group lens system including the front lens 5 and the second group lens system (not shown), and changes the distance between both lens groups to change the focal length. It constitutes a possible zoom lens.

A fixed opening 2e is provided at the center of the optical axis of the shutter holding member 2 and has a size such that the largest light flux can be transmitted from all the focal lengths from the wide angle range to the telephoto range. The shutter holding member 2 is integrally fixed with shutter blade support shafts 2a and 2b and aperture blade support shafts 2c and 2d. The shutter blade supporting shafts 2a and 2b are provided with shutter blades 3A and 3B which also serve as aperture blades.
a and 3b are fitted and rotatably supported by a shaft, and have an aperture / shutter mechanism for controlling exposure by combining the opening diameter and the opening / closing speed. In order to regulate the maximum aperture diameter by changing the maximum luminous flux diameter according to the change in the focal length of the taking lens separately from the shutter, the apertures 4a and 4b are fitted into the aperture blade support shafts 2c and 2d, respectively, and are rotatable. A diaphragm blade mechanism having pivotally supported variable diaphragm blades 4A and 4B is provided.

Generally, the diameter of a light beam passing therethrough changes according to the focal length. Therefore, when the shutter blades 3A and 3B are fully opened, separately from the fixed opening 2e of the shutter holding member 2,
Due to the variable aperture blades 4A and 4B, it is necessary to set and limit the maximum aperture diameter according to the focal length. For this purpose, the variable aperture blades 4A and 4B are provided. The shutter blades 3A and 3B are driven by drive pins (not shown) engaged with cam long holes 3c and 3d provided in the shutter blades 3A and 3B by a shutter opening / closing mechanism (not shown) interlocked with the photographing exposure operation. It is opened and closed. In addition, the variable aperture blade 4
A and 4B are interlocked with the variable focal length mechanism,
It is operated by driving a drive pin (not shown) engaged with c and 4d.

The shutter opening / closing mechanism is controlled based on an exposure condition automatically determined based on a measurement value of a photometric unit provided in the camera for measuring the brightness of a subject or an exposure condition set by a manual operation. Is done. Front lens 5
The rear surface side is a convex lens having a convex surface protruding toward the shutter holding member. In the present embodiment, the variable aperture blades 4 </ b> A, 4 </ b> A
The variable aperture blades 4A and 4B are arranged so that A ≧ 0 when the lap amount is A so that the operating plane of B wraps at the position in the optical axis direction. Variable aperture blade 4
A and 4B have their minimum apertures regulated so as not to come into contact with the surface of the lens 5.

The operation of the lens frame with a variable aperture mechanism of the camera according to the present embodiment will be briefly described. The focal length setting operation includes a first lens group including the front lens 5, and changes the focus between the lens frame 1 that forms the first group frame and the lens frame that forms the second lens group (not shown). Change the distance between the wide-angle range and the telephoto range.

When the set focal length is in a wide angle range,
In general, the maximum luminous flux passing through the diaphragm blades is smaller than that in the telephoto range. Therefore, the variable diaphragm blades 4A and 4B are set to the positions where the diaphragms are narrowed as shown in FIG. When the focal length is in the telephoto range, the maximum luminous flux passing through the diaphragm blades is thicker than in the wide-angle range, so that the variable diaphragm blades 4A and 4B are located at positions where the diaphragms are further opened as shown in FIG. In this way, the variable aperture blades 4A and 4B are interlocked according to the focal length to regulate and control the maximum light flux that can pass.

The maximum luminous flux diameter of the variable aperture blades 4A and 4B is controlled in accordance with the setting of a predetermined focal length. Thereafter, the shutter is driven by a photographing exposure start operation, and the shutter blades 3A and 3B are opened and closed. Then, the exposure amount passing through the photographing lens is controlled by setting the exposure aperture diameter and the opening time based on the exposure condition determined according to the brightness of the subject.

According to such an embodiment, the variable aperture blade is disposed at a position in which the variable aperture blade enters the optical axis direction from the top of the convex lens surface within a range that does not hit the convex lens surface, as compared with the conventional arrangement of the aperture blades. This makes it possible to reduce the distance L in the optical axis direction from the top of the lens surface to the shutter holding member and other lenses, as compared with the related art, and to reduce the size of the lens barrel and the camera incorporating the same.

Further, when the rear lens is located behind the shutter holding member, the distance between the lens group and the front lens 5 can be reduced, so that the degree of freedom in lens optical design can be increased. As a result, the size of the lens barrel can be reduced, and a camera having a lens with higher performance can be obtained. Further, in the case of a general two-unit zoom lens, when changing the focal length from the wide-angle side to the telephoto side, the entire lens is optically moved forward, and the front lens 5 and the rear lens sandwiching the shutter mechanism are used. Since the interval becomes narrower, according to the present embodiment, an optical design in which the focal length is extended to the telephoto side by the space in the optical axis direction conventionally occupied by the variable aperture blades becomes possible.

In this embodiment, the aperture diameter of the variable aperture blade is automatically controlled in conjunction with zooming. However, in addition to the zooming operation, the aperture diameter of the aperture blade is changed by a specific photographing mode switching operation or the like. The present invention can also be applied to a case in which the interlocking is made variable. Further, the present invention can also be applied to a case where a variable aperture blade that is varied according to the focal length is provided at an appropriate position in a lens barrel or a camera body as a so-called flare aperture that prevents harmful light from reaching the film surface.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIGS. 4, 5 and 6 show the second embodiment of the present invention.
FIG. 4 is a cross-sectional view of a main part of a lens barrel with a variable aperture mechanism of the camera according to the first embodiment. FIG. 4 shows a state in which the aperture of the aperture blade is largely open in a shooting preparation state, and FIG.
Indicates a state in which the aperture of the aperture blade is the smallest in the required range during photographing. FIG. 6 shows a retracted state in which the lens is retracted from the state shown in FIG. 4 so that the photographing lens prohibits photographing, and the aperture blades are made larger in diameter than the state shown in FIG. 5 so as not to interfere with the lens surface. It shows the state where it is.

The lens frame 21 has a shutter holding member 22 fixed thereto. On the front side of the shutter holding member 22, a lens holding frame 26 to which the front lens 25 is fixed is fitted to the lens frame 21 so as to be slidable in the optical axis direction. Here, the lens holding frame 26 is prevented from moving in the rotation direction by the hole 26 a being engaged with the guide shaft 27 that is erected in the lens mirror frame 21 in the optical axis direction. Moving the front lens 25 from the state shown in FIG. 4 to the state shown in FIG. 5 with respect to the subject at the time of shooting by moving straight ahead in the optical axis direction; and moving the front lens 25 from the state shown in FIG. Can be stored and moved to the collapsed state.

On the rear side of the shutter holding member 22, a rear group frame member having a rear lens (not shown) fixed to a frame member (not shown) is disposed, and moves coaxially with the lens frame 21. The focal length can be changed by making the distance between the front lens 25 and the rear lens variable. As described above, the lens frame of the present camera is the first lens group composed of the front lens 25 and the second lens group (not shown), and the focal length can be varied by varying the distance between both lens groups. The configuration of a simple zoom lens is the same as that of the first embodiment.

The shutter holding member 22 has shutter blade support shafts 22a and 22b and aperture blade support shafts 22c and 22c.
22d is integrally fixed. The shutter holding member 22 is provided with the shutter blade supporting shafts 22a and 22b.
The shutter blades 23A and 23B have holes 23a and 23, respectively.
3b is fitted and rotatably supported, controls the opening / closing waveform so as to always close after reaching the full opening diameter, and has a shutter mechanism for controlling the exposure by the opening / closing speed or the like.

In addition to the shutter mechanism, the shutter holding member 22 is provided in front of the shutter mechanism with aperture blade support shafts 22c and 22d for changing the aperture stop of the taking lens optical system to set the aperture diameter. Holes 24a, 24b
The variable aperture blade 24A rotatably supported by fitting the
A diaphragm blade mechanism having 24B is provided. In addition,
The shutter blades 23A and 23B are opened and closed by driving a drive pin (not shown) engaged with the cam long holes 23c and 23d in conjunction with a shutter release operation of the camera by a shutter opening / closing mechanism (not shown). Also, the aperture blades 24A, 2
4B is configured such that a driving pin (not shown) engaged with the cam long holes 24c and 24d is driven by a not-shown aperture blade opening / closing mechanism, and the opening diameter can be changed. The exposure amount at the time of photographing is controlled by changing a combination of the aperture of the aperture blade mechanism and the opening / closing time of the shutter mechanism according to the brightness of the subject.

As shown in the figure, the front lens 25 is a convex lens having a convex surface whose rear surface protrudes toward the shutter holding member. In the second embodiment, in the retracted state shown in FIG. 6 and the photographing preparation state shown in FIG.
As shown in the drawing, when the lap amount is A so that the operating surfaces of the A and 24B wrap at the position in the optical axis direction, A ≧
The aperture blades 24A and 24B are arranged so as to be zero.

FIG. 4 shows the preparatory position before the front lens 25 is extended from the retracted position and focused, and the aperture blades 24A and 24B have their aperture diameters considerably widened and interfere with the front lens 25. Not running away.
FIG. 5 shows a state in which the front lens 25 is focused on a subject at a short distance at the extended position in the focusing movement range, and the front lens 25 is extended to a position where it does not overlap with the operation plane of the aperture blades 24A and 24B. Therefore, the aperture diameter of the aperture blades 24A and 24B can be changed to any size. FIG. 6 shows a state where the front lens 25 is in the retracted position further retracted from the state shown in FIG. 4, and the vertex of the convex surface of the front lens 25 is closer to the shutter blades 23A and 23B. At this time, the aperture blade 24
A and 24B operate further in the opening direction so as not to interfere with the convex surface.

As described above, the variable aperture blades 24A, 24B
The minimum aperture of the front lens 25 is regulated in accordance with the extension position of the front lens in the optical axis direction so as not to contact the surface of the front lens 25. The operation of the lens barrel having the variable aperture mechanism according to the second embodiment will be briefly described.

In FIG. 4, when a camera release operation (not shown) is performed, the lens driving mechanism drives the lens holding frame 26 in a forward direction away from the variable aperture blades 24A and 24B. The lens driving mechanism is controlled by a CPU (Central Processing Unit) (not shown), and the CPU stops the lens holding frame 26 at a target stop position. When the lens holding frame 26 stops, the diaphragm blade driving mechanism drives the diaphragm blades 24A and 24B in the closing direction. The aperture blade driving mechanism is controlled by the CPU, and the CPU controls and stops the aperture blades 24A and 24B at a target stop position.

As shown in FIG. 5, aperture blades 24A, 24
When the shutter B stops, the shutter blades 23A and 23B are opened and closed by the shutter opening and closing mechanism, and the aperture blade 24 of the photographing lens is set as an exposure opening time according to the brightness of the subject.
The exposure amount passing through the aperture diameters of A and 24B is controlled. In the second embodiment, in the housed state, as in the first embodiment, the aperture blades are arranged closer to the lens than the top of the lens surface, so that from the top of the lens surface to the shutter holding member and other lenses. Can be made shorter than before, so that the size of the lens barrel can be reduced.

In the second embodiment, the aperture blades 24A and 24B are normally kept in an open state in which the aperture diameter is increased so as to avoid interference with the front lens 25. Since the aperture diameter is changed and driven after the lens 25 is separated from the aperture blades 24A and 24B in the optical axis direction, the aperture diameter of the aperture blades 24A and 24B can be freely reduced without being restricted by interference with the front lens 25. It is possible.

Further, when the lens barrel is folded and moved in the optical axis direction so as to shorten the lens interval so as to be in the housed state, as shown in FIG.
The openings of A and 24B are further widened as compared with the photographing preparation state of FIG. 4, and the amount of wrap between the lens surface top and the aperture blades 24A and 24B can be increased, so that the size can be reduced for convenience in carrying. [Appendix] According to the above-described embodiment of the present invention as described in detail above, the following configuration can be obtained.

(1) A variable aperture blade whose aperture diameter can be changed so as to regulate light to be exposed and which does not become fully closed,
A lens disposed adjacent to the aperture blade, at least a surface facing the aperture blade is a convex surface, and the position of the aperture blade in the optical axis direction is the same as the top of the convex surface of the lens. Or a lens frame with a variable diaphragm mechanism for a camera, wherein the lens frame is disposed at a position that enters the lens surface side from the surface top.

(2) A shutter blade that transmits and exposes light by opening and closing, a variable aperture blade whose opening diameter can be changed so as to regulate the diameter of a passing light beam to be exposed, and is not in a fully closed state, It is arranged adjacent to the aperture blade,
A lens whose surface facing at least the diaphragm blade is a convex surface, and the position of the diaphragm blade in the optical axis direction is the same as the convex surface of the lens, or the lens surface side of the convex surface. A lens frame with a variable aperture mechanism for a camera, wherein the lens frame is disposed at a position where the lens barrel has entered.

(3) a variable aperture blade whose aperture diameter can be changed so as to regulate light to be exposed and which does not become fully closed;
A lens disposed adjacent to the diaphragm blade, at least a surface facing the diaphragm blade is a convex surface, and a lens driving mechanism for moving the lens back and forth in the optical axis direction,
The position of the aperture blade in the optical axis direction, when the lens is closest to the aperture blade by the lens drive mechanism,
A lens barrel with a variable diaphragm mechanism for a camera, wherein the lens barrel is disposed at the same position as the convex surface of the lens or at a position on the lens surface side of the convex surface.

(4) a variable aperture blade whose aperture diameter can be changed so as to regulate the light to be exposed and which does not become fully closed;
An aperture blade opening / closing mechanism for driving the aperture blade to open and close; a lens arranged adjacent to the aperture blade, at least a surface facing the aperture blade being a convex surface; and a lens drive for moving the lens back and forth in the optical axis direction. And a position in the optical axis direction of the diaphragm blade, when the lens is closest to the diaphragm blade by the lens driving mechanism, the same as the convex top of the lens, or from the vertex. The diaphragm blades are also arranged at positions where they enter the lens surface side, and the aperture blades are set to an initial state in which the aperture diameter is open, and after the lens is moved in a direction away from the aperture blades by the lens driving mechanism, the diaphragm blades A lens barrel with a variable diaphragm mechanism for a camera, which is driven by a blade drive mechanism in a direction to reduce the opening diameter.

(5) In Supplementary note 3, further comprising an aperture stop blade opening / closing mechanism for opening and closing the aperture blade, a zoom optical system, and a focal length changing means for changing a focal length of the zoom optical system. A lens frame with a variable aperture mechanism for a camera, wherein the aperture blade drive mechanism operates in conjunction with the focal length changing means.

(6) In Appendix 4, the camera is
A lens frame with a variable aperture mechanism for a camera, comprising: a photometer for measuring the brightness of a subject, wherein the aperture blade driving mechanism is controlled based on a photometric value measured by the photometer. (7) In the supplementary note 4, the camera has an exposure condition setting means for changing an exposure condition, and the aperture blade driving mechanism is controlled based on a condition set by the exposure condition setting means. Lens frame with a variable aperture mechanism for the camera.

(8) a variable aperture blade whose aperture diameter can be changed so as to regulate the light to be exposed and which does not become fully closed;
An aperture blade opening / closing mechanism for driving the aperture blade to open and close, a variable focal length lens optical system, a focal length changing unit for changing a focal length of the variable focal length lens optical system, and the lens optical system. A lens having a convex surface at least facing the diaphragm blade and a lens driving mechanism for moving the lens back and forth in the optical axis direction in conjunction with the focal length changing means. And an aperture interlocking mechanism that operates the aperture blade driving mechanism in conjunction with the focal length changing unit, wherein the position of the aperture blade in the optical axis direction is such that the lens is driven by the lens driving mechanism to stop the aperture. When it is closest to the blade, it is arranged at the same position as the convex surface of the lens, or at a position that enters the lens surface side from the surface vertex, and the diaphragm blade is
The aperture opening mechanism by the aperture interlocking mechanism is set to an initial state, and as the lens moves in a direction away from the aperture blade by the lens driving mechanism, the lens is driven by the aperture blade driving mechanism in a direction to reduce the aperture diameter. A lens barrel with a variable aperture mechanism for a camera.

[0039]

As described above, according to the lens barrel having the variable aperture mechanism according to the present invention, the variable aperture blade is
By arranging the lens so that it does not hit the convex lens surface and enters the optical axis direction from the surface apex, it is possible to shorten the distance in the optical axis direction from the lens surface apex to the shutter holding member and other lenses. Yes, the lens barrel can be downsized.

Further, since the distance between the lens groups sandwiching the variable aperture blade can be shortened, the degree of freedom in lens optical design can be increased, and a lens barrel with higher performance can be obtained. . Furthermore, in the case of a lens that moves in the optical axis direction during non-shooting, shooting, and in use, when the lens is moved in the optical axis direction from the variable aperture blade wrapped in the optical axis direction with the lens. When the aperture diameter is changed and driven later, the aperture diameter of the variable aperture blade can be freely reduced without being restricted by interference with the lens.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a main part of a lens barrel with a variable aperture mechanism of a camera according to a first embodiment of the present invention, viewed obliquely from the front.

FIG. 2 is a sectional view of a main part of a lens barrel with a variable aperture mechanism of the camera according to the first embodiment of the present invention, showing a state where the apertures of variable aperture blades 4A and 4B are the smallest.

FIG. 3 is a sectional view of a main part of a lens barrel with a variable aperture mechanism of the camera according to the first embodiment of the present invention, showing a state where the apertures of the variable aperture blades 4A and 4B are the most open;

FIG. 4 is a cross-sectional view of a main part of a lens barrel having a variable aperture mechanism of a camera according to a second embodiment of the present invention. This shows a state where the aperture is largely open.

FIG. 5 is a cross-sectional view of a main part of a lens barrel with a variable aperture mechanism of a camera according to a second embodiment of the present invention, in which the aperture of an aperture blade is the smallest in a required range during photographing. Is shown.

FIG. 6 is a sectional view of a main part of a lens barrel with a variable aperture mechanism of a camera according to a second embodiment of the present invention, in which the lens is shifted from the state shown in FIG. FIG. 4 shows a state in which the variable aperture blade is in a retracted state in which it is stored, and has a larger diameter than the state shown in FIG. 4 so as not to interfere with the lens surface.

FIG. 7 is a cross-sectional view of a principal part showing a lens barrel with a variable aperture mechanism of a conventional camera.

[Explanation of symbols]

 1, 21 Lens frame 2, 22 Shutter holding member 3A, 3B, 23A, 23B Shutter blade 4A, 4B, 24A, 24B Variable aperture blade 5, 25 Front lens 26 Lens holding frame 27 Guide shaft

Claims (3)

[Claims] 1. A photographing lens optical system, a variable aperture blade provided in the photographing lens optical system, the aperture diameter of which can be changed so as to regulate a passing light beam of light to be exposed, and a part of the photographing optical system. And a lens disposed adjacent to the diaphragm blade and having at least a surface facing the diaphragm blade being a convex surface. The position of the working surface of the diaphragm blade in the optical axis direction is a convex surface of the lens. A lens barrel with a variable diaphragm mechanism for a camera, wherein the lens barrel is disposed at a position that enters the lens surface side from the surface top of the lens. 2. A photographing lens optical system, a variable aperture blade provided in the photographing lens optical system, the aperture diameter of which can be changed so as to regulate a passing light beam of light to be exposed, and a part of the photographing optical system. And a lens driving mechanism for moving the lens back and forth in the optical axis direction, the lens being arranged adjacent to the diaphragm blade and having at least a surface facing the diaphragm blade being a convex surface. The position of the working surface in the optical axis direction is arranged at a position where the lens is closer to the lens surface side than the convex top of the lens when the lens is closest to the diaphragm blade by the lens driving mechanism. A lens barrel with a variable diaphragm mechanism for a camera. 3. A photographing lens optical system, a variable diaphragm blade provided in the photographing lens optical system, the aperture diameter of which can be changed so as to regulate a passing light beam of light to be exposed, and a diaphragm for driving the diaphragm blade to open and close. A blade opening / closing mechanism, a lens that constitutes a part of the photographing optical system, is disposed adjacent to the diaphragm blade, and has a convex surface at least facing the diaphragm blade; and moves the lens back and forth in the optical axis direction. And a lens driving mechanism for causing the diaphragm blade to have a position in the optical axis direction of the working surface of the diaphragm blade when the lens is closest to the diaphragm blade by the lens driving mechanism. The diaphragm blade is disposed at a position that enters the lens surface side, and
The camera is characterized in that the aperture is substantially open, and when the lens is moved in a direction away from the diaphragm blade by the lens driving mechanism, the lens is driven by the diaphragm blade driving mechanism in a direction to reduce the aperture diameter. Lens frame with variable aperture mechanism.