JP3453536B2 - Conversion lens mounting mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conversion lens mounting mechanism for mounting a conversion lens.

[0002]

2. Description of the Related Art Conventionally, it is necessary to change the range of the focal length of the lens device 1 in order to make various images. For this purpose, a conversion lens 9 such as a wide converter or a teleconverter is used as shown in FIG. It is necessary to attach it to the focus lens barrel 1b provided at the tip of the main body 1a of the lens device 1. During the focusing operation, the conversion lens 9 is rotated together with the lens barrel 1b to move back and forth.

[0003]

However, in the conversion lens mounting mechanism of the above-mentioned conventional example, since the conversion lens 9 is mounted on the focus lens barrel 1b at the tip of the lens device 1, the conversion lens is mounted during the focusing operation. There is a problem that the conversion lens 9 puts a heavy load on the lens apparatus 1 while the lens 9 moves forward and backward while rotating with the focus lens barrel 1b. For example, when the weight of the 15 × lens device 1 for television is 1600 g, the weight of the conversion lens 9 to be attached is 1200 g, and the lens device 1 has 75% of the weight.
The weight of things will be applied to the tip. Therefore, when focusing manually, it becomes difficult to focus, and when focusing electrically, there is a problem that the torque is insufficient and the focusing speed decreases, and in the worst case, focusing is not possible. is there.

An object of the present invention is to solve the above-mentioned problems and to provide a conversion lens mounting mechanism capable of smoothly and reliably performing a focusing operation.

[0005]

In order to achieve the above object, a conversion lens mounting mechanism according to the present invention is mounted such that a conversion lens can be mounted in front of a lens barrel for photographing which is composed of a fixed portion and a movable portion. A mechanism, a mounting frame for arranging the conversion lens in front of the front end of the photographing lens barrel, a mounting frame fixed to one end through an optical axis adjusting means, and the other end fixed to the photographing lens mirror. The optical axis adjusting means is fixed to a fixed part of the tube, and a supporting member for supporting the conversion lens via a mounting frame is provided. The optical axis adjusting means is the optical axis of the photographing lens barrel and the conversion lens. Of the photographing lens barrel to mechanically interfere with the conversion lens during movement in the optical axis direction for focusing by the movable part. Characterized in that the odd.

A conversion lens mounting mechanism according to the present invention is a mounting mechanism capable of mounting a conversion lens in front of a photographic lens barrel having a movable portion, wherein the conversion lens is attached to a front end of the photographic lens barrel. A mounting frame disposed in front of the optical axis adjusting unit, and one end fixed to the mounting frame through an optical axis adjusting unit and the other end fixed to a fixed unit of the camera for photographing, and the optical axis adjusting unit through the mounting frame. A supporting member for supporting a conversion lens, the optical axis adjusting means adjusts a relative relationship between an optical axis of the photographing lens barrel and an optical axis of the conversion lens, and the photographing lens barrel is movable. It is characterized in that it does not mechanically interfere with the conversion lens during movement in the optical axis direction for focusing by the unit.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a side view of the conversion lens mounting mechanism of the first embodiment, and FIG. 2 is a bottom view thereof. A lens device 71 is composed of a lens main body 72 and a focus system lens barrel 73. A conversion lens 75 is attached via a lens attachment frame 74. The lens mounting frame 74 is the lens body 7
It is attached to a support plate 76 fixed to the lower part of 2 through an adjustment stand 77. As shown in FIG. 3, the support plate 76 has adjustment screws 78, 7 for adjusting the inclination of the adjustment table 77.
9 and 80 are screwed together, and the adjustment stand 77 has these adjustment screws 7
Support plate 76 so as to contact the tips of 8, 79 and 80
It is fixed to the screw with fixing screws 81 and 82.

On the other hand, one side of the lens mounting frame 74 is shown in FIG.
As shown in FIG. 5, a fitting hole 74a for fitting the focus system barrel 73 of the lens device 71 is provided. The fitting hole 74a is formed so that the optical axes of the lens device 71 and the conversion lens 75 coincide with each other when the lens barrel 73 is loosely fitted and rotates smoothly. Therefore, when the lens mounting frame 74 tilts and the lens barrel 73 and the fitting hole 74a interfere with each other, the lens device 71 and the conversion lens 75
This means that the optical axes of are not aligned. A fixing hole 74b for fixing the conversion lens 75 and a contact surface 74c for determining the position of the conversion lens 75 in the optical axis direction are provided on the other side of the lens mounting frame 74. A buffer member may be provided inside the lens mounting frame 74 so that the lens barrel 73 can stably rotate in the fitting hole 74a even when the lens mounting frame 74 is deformed due to an impact or the like.

With such a configuration, the lens mounting frame 74
In order to match the optical axis of the lens barrel 73 with the optical axis of the lens barrel 73, first loosen the fixing screws 81 and 82, and use the play amount of the holes for passing the fixing screws 81 and 82 in the X and Y directions as shown in FIG. The adjusting screws 78, 79, 80 are moved in the Z direction by the same amount.
In addition, in order to rotate around the X axis, the adjustment screw 7
In order to move 9 and 80 in opposite directions and rotate about the Y-axis, adjusting screws 79 and 80 are moved in the same direction by the same amount and adjusting screw 78 is moved in the opposite direction. Further, in order to rotate around the Z axis, the play amount of the holes through which the fixing screws 81 and 82 are inserted is utilized as in the case of moving in the X and Y directions. After the optical axis is detected in this way, the fixing screws 81 and 82 are tightened.

The positional relationship between the lens device 71 whose optical axis is adjusted and the conversion lens 75 is shown in FIGS. 5 (a), 5 (b) and 5 (c) with the lens mounting frame 74 removed. 5 (a) shows the case where the focal length of the conventional example is infinite, and FIG.
FIG. 5B shows the case where the focal length is very close in this embodiment, and FIG. 5C shows the case where the focal length is infinity in this embodiment. The conversion lens 75 is not moved by the movement amount D of the lens device 71.

In this embodiment, the optical axis can be detected without looking at the image, and since the conversion lens 75 is actually afocal, the optical axis accuracy is sufficient even with such a manual adjustment. Can be kept. In addition,
It is not necessary to provide an adjusting mechanism for the portion where accuracy is maintained during assembly, and conversely, if it is desired to widen the adjustment range, more adjusting mechanisms can be provided. Further, an adjustment mechanism may be provided in the thrust direction of the support plate 76 so as to be compatible with all types of lens devices 71. Further, the lens mounting frame 74 may be detachable and replaceable for downsizing, and the support plate 76 may be formed integrally with the lens device 71.

FIG. 6 is a side view of the second embodiment, and FIG. 7 is a front view showing a case where the lens device 71 is attached to the camera body 83. A tripod mounting plate 84 is fixed to the lower surface of the camera body 83, and a support plate 85 for fixing the lens mounting frame 74 is fixed to the lower surface of the tripod mounting plate 84 with screws 8.
It is fixed by 6, 87. A bearing 88 is horizontally rotatably attached to the tip of the support plate 85, and is fixed by a knob 89. A shaft portion 90 is tiltably fitted to the bearing portion 88, and is fixed by a knob 91. A guide ring 92 is fitted onto the shaft portion 90 so as to be vertically movable and rotatable,
A lens mounting frame 74 is fitted to the lens holder 2 so as to be vertically movable and rotatable, and is fixed by a knob 93.

With such a configuration, the lens mounting frame 74
In order to adjust the optical axis of the
The optical axis direction X is adjusted by loosening 9 and moving the bearing portion 88 back and forth. Also, the vertical direction Z is adjusted by loosening the knob 93 and moving the lens mounting frame 74 up and down.
The tilt angle α is adjusted by loosening the knob 91 and tilting the lens mounting frame 74 back and forth. Further, as shown in the plan view of FIG. 9, by loosening the knob 89 and moving the lens mounting frame 74 left and right, the Y direction perpendicular to the X direction and the Z direction is adjusted, and the knob 93 is loosened to move the lens mounting frame 74. The tilt angle β of the lens in the left and right direction is adjusted by rotating the lens to the left and right.

In this embodiment, five degrees of freedom are set between the lens device 71 and the conversion lens 74, but the optical axis accuracy can be maintained without setting such five degrees of freedom. However, these degrees of freedom may be reduced.

FIG. 10 is a side view of the third embodiment. A lens supporter 94 is attached to a tripod mounting plate 84,
The lens device 71 includes the lens supporter 9 via the fixing portion 95.
It is attached to 4. The fixing portion 95 may be attached so that it can be fixed to various mounting portions.

FIG. 11 is a side view of the fourth embodiment. An accessory fixing bar 96 is attached to the camera body 83, and a lens mounting frame 74 is attached to the accessory fixing bar 96 via a fixing portion 97. There is. This fixed part 9
7 is attached to an accessory fixing bar 96 so as to be movable back and forth and fixed by a knob 98.

The accessory fixing bar 96 is a camera body 83.
It may be fixed anywhere, and the fixing portion 97 may be fixed to various mounting portions as an attachment.

FIG. 12 is a side view of the fifth embodiment, in which the camera body 83 is a frame 9 such as a wall, a rack, a housing or the like.
The lens attachment frame 74 is attached to the frame 99 via the fixing portion 100. The fixed portion 100 is fixed to the frame 99 with screws 101. Fixed part 1
00 and the camera main body 83 are held in a fixed positional relationship, the lens mounting frame 74 may be fixed anywhere. Also,
There is no problem even if the fixing portion 100 can be fixed to various mounting portions as an attachment.

[0019]

As described above, in the conversion lens mounting mechanism according to the present invention, since the lens barrel for the photographing lens can freely operate with respect to the conversion lens, only the conversion lens is detached and photographing is performed as usual. The conversion lens can be easily replaced and used. In addition, the current product can be used without modification, so installation is simple and economical. Furthermore, since the weight of the conversion lens is not limited, it is possible to use a higher performance conversion lens.

[Brief description of drawings]

FIG. 1 is a side view of a conversion lens mounting mechanism according to a first embodiment.

FIG. 2 is a bottom view.

FIG. 3 is a partially exploded perspective view.

FIG. 4 is a sectional view of an optical axis detecting means and an optical axis adjusting means.

FIG. 5 is an explanatory diagram of a positional relationship between a lens device and a conversion lens.

FIG. 6 is a side view of the second embodiment.

FIG. 7 is a front view.

FIG. 8 is an explanatory diagram of an optical axis adjusting method.

FIG. 9 is an explanatory diagram of an optical axis adjusting method.

FIG. 10 is a side view of the third embodiment.

FIG. 11 is a side view of the fourth embodiment.

FIG. 12 is a side view of the fifth embodiment.

FIG. 13 is a side view of a conventional example.

[Explanation of symbols]

71 Lens device 74 Lens mounting frame 75 conversion lens 76,85 Support plate 83 Camera body 84 Tripod mounting plate 89, 91, 93, 98 knobs 92 Guide ring 94 lens supporter 95, 97, 100 Fixed part 96 accessory fixing bar

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Setsuo Yoshida               53 Imauemachi, Nakahara-ku, Kawasaki-shi, Kanagawa               Canon Inc. Kosugi Office (72) Inventor Haruhisa Yamamoto               53 Imauemachi, Nakahara-ku, Kawasaki-shi, Kanagawa               Canon Inc. Kosugi Office (72) Inventor Kasei Watanabe               53 Imauemachi, Nakahara-ku, Kawasaki-shi, Kanagawa               Canon Inc. Kosugi Office

Claims (4)

(57) [Claims] 1. A mounting mechanism capable of mounting a conversion lens in front of a lens barrel for photographing, which comprises a fixed portion and a movable portion, wherein the conversion lens is arranged in front of a front end portion of the lens barrel for photographing. The mounting frame to be arranged is fixed to one end through the optical axis adjusting means and the other end is fixed to the fixed portion of the photographing lens barrel, and the conversion is performed via the optical axis adjusting means and the mounting frame. A supporting member for supporting the lens, wherein the optical axis adjusting means adjusts the relative relationship between the optical axis of the photographing lens barrel and the optical axis of the conversion lens to obtain the photographing lens mirror. The conversion lens mounting mechanism, wherein the barrel is configured so as not to mechanically interfere with the conversion lens during movement in the optical axis direction for focusing by the movable portion. 2. A mounting mechanism capable of mounting a conversion lens in front of a photographic lens barrel having a movable part, wherein the conversion lens is arranged in front of a front end portion of the photographic lens barrel. And a support member which is fixed to the mounting frame at one end via an optical axis adjusting means and is fixed at the other end to a fixed portion of a photographing camera to support the conversion lens via the optical axis adjusting means and the mounting frame. The optical axis adjusting means adjusts a relative relationship between an optical axis of the photographing lens barrel and an optical axis of the conversion lens, and the photographing lens barrel is a light for focusing by the movable portion. A conversion lens mounting mechanism, characterized in that it does not mechanically interfere with the conversion lens during movement in the axial direction. 3. A lens barrel equipped with the mounting mechanism according to claim 1. 4. An imaging camera equipped with the mounting mechanism according to claim 2.