JPH10161000A - Fixed focus lens type camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the inclination of an optical axis, eccentricity, focus misalignment, etc., by providing the camera with a macro extending means which moves a lens barrel along a rotation regulating means when pressed to a back focus adjusting member in contact therewith. SOLUTION: The lens barrel 1 is moved longitudinally along the optical axis by turning a turning lever 6 disposed at the back focus adjusting ring 2 screwed to the lens barrel 1 prepressurized by an annular prepressurizing spring 7, by which the back focus (focus) is aligned and the back focus adjusting ring 2 is adhered and fixed to the lens barrel 1 in this turning position. Macrophotography is executed by rotating a turning lever 4 from a start position to rotate the macro extending ring 3, rotating this ring until the turning lever 4 comes into contact with the stop side end face of the notched end face of the stationary lens barrel 5, thereby extending the lens barrel 1 to the length set forward along the optical axis. The returning to the ordinary photographing position is executed by returning the turning lever 4 to the original notched start side end face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed focus lens type camera having a macro photographing means used for video equipment such as a silver halide camera and an electronic still camera, and more particularly to an improvement of a lens barrel.

[0002]

2. Description of the Related Art A silver halide camera, an electronic still camera, and the like having a macro photography (close-up photography) function in addition to a normal photography function with a fixed focus lens are widely known. As shown in FIG. 5, the lens barrel used for this is a lens barrel 21 for back focus adjustment and macro extension.
A mechanism for rotating the lens barrel 21 along the optical axis by a screw 26 formed between the screw section formed on the lens barrel and the screw section of the fixed barrel section. The positioning of the lens barrel after the back focus adjustment is completed is achieved by the stoppers provided on the notched end faces 22a and 22b of the feeding ring 22 which is fitted and attached to the outer shape of the lens barrel and the fixed barrel 23. 24. In this method, the lens barrel 21 is rotated to adjust the back focus, a focus position is set at an arbitrary distance, and the extension ring 22 is fitted into the lens barrel 21 at the lens barrel rotation position.
The start side 24a of the stopper 24 provided on the fixed lens barrel is brought into contact with the feed start side end face 22a of the feed amount control notch shown in FIG. Then, the fixing screw 25 provided on the feeding ring 22 is tightened to be fixed integrally with the lens barrel 21. When performing macro photography, the feeding ring 22 is rotated to stop the end portion of the cutout portion for restricting the feeding amount. The lens barrel 21 is rotated until the stopper 24b on the fixed barrel side comes into contact with the stopper 22b, and the lens barrel 21 is moved forward by an arbitrary amount of extension. To return to the normal photographing state, the feeding ring 22 is rotated in the reverse direction and rotated until it hits the stopper 24a.

[0003]

However, in the prior art, during back focus adjustment or macro extension, the entire lens barrel is rotated. Of the optical axis due to tilting, eccentricity, etc., and one-sided blurring occurs within the effective imaging range at the focal position. The tilt of the optical axis, the eccentricity, the shift of the focal position, and the like occur due to the looseness of the screw and the like, causing a problem in optical performance.

Further, since the extension ring is fitted into the lens barrel after the back focus adjustment, carefully and accurately abuts against the stopper, and is fixed with screws, a delicate work and a lot of assembly time are required. Workability was never good. The present invention aims to solve these problems of the prior art.

[0005]

According to the present invention, there is provided a fixed focal length lens system in which a fixed lens barrel has a lens barrel movable along the optical axis of the lens, and the lens barrel is extended to enable macro photography. In a camera, a pressurizing section for pressing the lens barrel to a focal plane on a fixed barrel side along a lens optical axis, and a back focus formed on the lens barrel and resisting pressurization of the pressurizing section. A back focus adjusting member that adjusts the position of the lens, a rotation restricting portion formed on the fixed lens barrel, that restricts rotation of the lens barrel, and enables movement of the lens barrel in the lens extension direction, and the back focus. A fixed focal length lens provided between the adjusting member and the fixed lens barrel, the macro focus extending means being provided with a macro feeding means for moving the lens barrel along the rotation restricting portion by pressing and contacting the back focus adjusting member; It provides a view camera. that time,
After the back focus adjustment, the macro lens feeding means may be adjusted by fixing the lens barrel and the back focus adjustment member.

[0006] Specifically, it engages with the rotation restricting guide portion,
The lens barrel, which has a threaded part to be screwed to the back focus adjustment ring and a fitting part to be fitted to the macro feed ring, is pressed to the focal plane side by a pressure spring member on the outer peripheral part on the front side of the lens barrel, and backlash due to screw backlash etc. The lens barrel is moved in the front-back direction along the optical axis by rotating the rotating lever of the screwed back focus adjustment ring, etc.
Perform back focus (focus) and fix the adjustment ring with adhesive. Thus, positioning and fixing during normal photographing are easily and easily performed. At this time, since the lens barrel does not rotate, there is no occurrence of eccentricity of the entire lens barrel or one-sided blurring due to tilting, eccentricity, optical axis shift or the like of each lens in the lens barrel. In macro photography, the macro extension ring provided behind the back focus adjustment ring is rotated to move the lens barrel forward by the extension amount along the optical axis. The front side of the extension ring has a sliding contact surface with a small contact area that slides on the rear end surface of the back focus adjustment ring, and the rear end surface has a cam surface, and the sliding contact between the cam surface and the convex portion on the fixed barrel side. By moving the lens barrel along the optical axis, the rotation lever integrated with the payout ring comes into contact with the end face of the payout amount regulating groove or notch provided on the fixed barrel side, and the lens reaches an arbitrary amount. The lens barrel is extended. The length of the feeding restricting groove or notch is set in accordance with the feeding amount. Even during macro shooting, the lens barrel does not rotate, so that one-sided blur or the like does not occur for the same reason as described above.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1, 2 and 3 are schematic views of the configuration of the embodiment of the present invention. In the drawings, the same parts are denoted by the same reference numerals. In FIG. 1, reference numeral 1 denotes a lens barrel engaged with a guide portion 9 of a fixed lens barrel 5 described later, which also serves as a lens barrel rotation control and movement guide, 2 denotes a back focus adjustment ring screwed with the lens barrel 1, Numeral 3 is fitted into the lens barrel 1 and slidably contacts the sliding end face 2 ′ of the back focus adjustment ring 2,
A macro feeding ring having a feeding cam portion 3 ′ on the opposite surface, 4 is a rotating lever provided on the macro feeding ring 3, and 5 is a feeding amount that comes into contact with a rotating lever 4 provided on the macro feeding ring 3. A fixed lens barrel having regulating notch end faces 5a, 5b and a convex part 5c slidingly contacting the feeding cam part 3 ', 6 is a rotating lever provided on the back focus adjustment ring 2, and 7 is the lens barrel 1 A ring-shaped pressurizing spring pressurizes the lens in the direction of the focal plane.
Screwed part that is screwed with the screw part.

Next, the operation in such a configuration will be described. The rotation lever 6 provided on the back focus adjustment ring 2 screwed to the lens barrel 1 pressurized by the ring-shaped pressurizing spring 7 is rotated to move the lens barrel 1 in the front-back direction along the optical axis. It is moved to adjust the back focus (focus), and the back focus adjustment ring 2 is adhesively fixed to the lens barrel 1 at the rotation position. When the back focus is adjusted as shown in FIG. 2, the rotating lever 4 provided on the macro extending ring 3 is rotated in advance, and the rotating lever 4 is attached to the start side end face 5a of the cutout for regulating the macro extending amount of the fixed lens barrel 5. Abut. In macro photography, the rotation lever 4 is rotated from the start position, the macro feeding ring 3 is rotated, and the rotation lever 4 is rotated until the rotation lever 4 comes into contact with the stop-side end surface 5b of the cutout end surface of the fixed lens barrel 5, and the lens barrel is rotated. 1 is advanced by a predetermined amount along the optical axis. As shown in FIG. 3, the rotation of the feeding ring 3 causes the feeding cam portion 3 ′ to slide on the surface of the convex portion 5 c of the fixed lens barrel 5, so that the back focus adjusting ring 2 adhered and fixed to the lens barrel 1. The lens barrel 1 is extended by moving the sliding contact surface 2 'forward. To return to the normal photographing position, the rotation lever 4 is returned to the original notch start side end face 5a.

[0009]

As described above, according to the configuration and the method of the present invention, there is no screwing-out of the lens barrel and the fixed lens barrel at the time of back focus adjustment or macro extension, so that there is no screw play. Therefore, there is no tilt of the optical axis, eccentricity, and deviation of the focal position. Also, at this time, since the entire lens barrel does not rotate, no eccentricity of the entire lens barrel or the occurrence of one-sided blurring due to the falling or eccentricity of each lens in the lens barrel does not occur in the effective screen.

Further, the back focus can be easily adjusted by rotating the adjustment ring, and can be accurately adjusted by reducing the screw pitch at which the adjustment ring and the lens barrel are screwed. And, in the macro feed,
Since the lens barrel does not move in rotation, the same optical problem does not occur. Since these can be formed with a simple configuration and there is no screwed portion between the lens barrel and the fixed barrel, there is no need to apply sliding grease or the like, so that assembly and adjustment workability is very good.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an embodiment of the present invention.

FIG. 2 is a schematic top view showing an embodiment of the present invention.

FIG. 3 is a schematic view of a feeding cam portion viewed from above.

FIG. 4 is a schematic side view of a conventional example.

FIG. 5 is a schematic diagram of a top surface of a conventional example.

[Explanation of symbols]

 1: lens barrel 2: back focus adjustment ring 2 ': sliding surface 3: macro feeding ring 3': feeding cam sliding portion 4: macro feeding ring rotating lever 5: fixed lens barrel 5a: macro feeding start surface 5b : Macro feed stop surface 5c: Sliding contact convex portion 6: Back focus adjustment rotation lever 7: Pressurizing spring 8: Screw threaded portion 9: Rotation restricting guide portion 21: Lens barrel 22: Feeding ring 22a: Start surface 22b : Stop surface 23: Fixed lens barrel 24: Stopper 25: Fixed screw 26: Screwed part

Claims (2)

[Claims] 1. A fixed-focus lens type camera in which a lens barrel is movable along an optical axis of a lens in a fixed barrel, and the lens barrel is extended to enable macro photography. A pressurizing unit configured to pressurize the focal plane on the fixed barrel side along the lens optical axis; and a back focus adjusting member formed on the lens barrel and adjusting a back focus against pressurization of the pressurizing unit. A rotation restricting portion formed on the fixed lens barrel, for restricting rotation of the lens barrel and enabling movement of the lens barrel in the lens extending direction; A fixed length lens type camera provided with a macro feed-out means provided between the first lens and the second lens to move the lens barrel along the rotation restricting portion by pressing and contacting the back focus adjusting member. Mela. 2. The fixed focus lens type camera according to claim 1, wherein after the back focus adjustment, the macro lens extending means is adjusted by fixing the lens barrel and the back focus adjustment member.