JPH0310105B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zoom lens for a camera, and more particularly to a so-called two-hand operated zoom lens that enables macro photography by making simple improvements.

Recently, zoom lenses for cameras have become mainstream, with a so-called macro mechanism that allows for close-up photography in addition to normal distance photography. However, all conventional zoom lenses with macro mechanisms use a separate helicoid for the macro mechanism in order to increase the amount of lens extension in the macro range, and require means for switching between the helicoid and the helicoid for normal distance photography. The lens structure was very complicated and expensive.

On the other hand, the shortest shooting distance of a zoom lens is determined by the focal length within the zooming range where the greatest vignetting (lack of peripheral light) occurs; at other focal lengths, the minimum shooting distance is determined by sufficient peripheral light. It has the potential to be made shorter. Generally, even if the shortest photographing distance is shortened at both ends of the zooming range, that is, the longest focus and the shortest focus, the problem of insufficient peripheral light does not occur.

Based on this perspective, the present invention enables close-up photography by directly using the focusing mechanism of a zoom lens, without requiring a special helicoid for macro photography or a switching mechanism for normal distance photography. It was designed for the purpose of regulating the range of movement of the focusing ring in so-called two-handed zooming, in which focusing is performed by rotating a focusing ring supported on a fixed lens barrel, and zooming is performed by rotating a zooming ring supported on a fixed lens barrel. The guide groove is composed of a focusing groove in the circumferential direction, a macro groove in the circumferential direction separated from the macro groove in the optical axis direction, and a conversion groove in the optical axis direction that connects both grooves. When transitioning from the focusing groove to the macro groove along the conversion groove, a zooming lock body supported on a fixed lens barrel so as to be movable in the optical axis direction while restricting rotation, and a zooming operation ring formed on the zooming operation ring. It is characterized in that the zooming operation ring is locked by the action of the zooming lock groove into which the zooming lock plate is inserted when the zooming ring itself is at the shortest focus or the longest focus. In other words, according to the zoom lens of the present invention, when the zooming operation ring is at the shortest focus or the longest focus, the focusing operation ring can be moved in the optical axis direction to shift to macro photography. Locked.

The invention will now be described with reference to the illustrated embodiments. The lens system shown in this embodiment consists of two groups, a front group lens L1 and a rear group lens L2. The front group lens L1 is attached to the front frame 11, and the rear group lens L2 is attached to the rear frame 12 by well-known means. Fixed. The fixed lens barrel 13 fixed to the camera body has a mount ring 1
4. Consists of a connecting ring 15 and an adjusting ring 16,
The adjustment ring 16 has a screw 18 into which the drive ring 17 is screwed.
is formed. The rear frame 12 is connected to this drive ring 1.
It is fitted onto the inner periphery of 7. A helicoid ring 19 is fitted onto the outer periphery of the drive ring 17, and the front frame 11 is screwed into the helicoid 20 of this helicoid ring 19.

A focusing operation ring 21 is provided on the outer periphery of the joint ring 15.
A zooming operation ring 22 is rotatably fitted therein. The zooming operation ring 22 and the drive ring 17 rotate integrally, and when the drive ring 17 rotates, it fits into a cam groove formed in the drive ring 17 and this cam groove. By the action of the guide pins implanted in the rear frame 12 and the helicoid ring 19, the rear frame
2 and the helicoid ring 19, that is, the front frame 11, move in the optical axis direction in a predetermined relationship, and the focal length of the lens system consisting of the front group lens L1 and the rear group lens L2 changes. An interlocking mechanism including such a cam groove and a guide pin is well known, and since the present invention is not concerned with these mechanisms, illustration of this mechanism is omitted.

A linear groove 23 in the optical axis direction is bored in the focusing operation ring 21, and a rotation transmission pin 24 implanted in the front frame 11 is fitted into this linear groove 23, so that when the focusing operation ring 21 is rotated, The front frame 11 rotates together, and as the front frame 11 rotates, the helicoid 20
Accordingly, it moves forward and backward in the optical axis direction for focus adjustment. Further, a guide pin 25 is fixed to this focusing operation ring 21, and this guide pin 25 is fitted into a guide groove 30 formed in the joint ring 15, so that the movement range of the focusing operation ring 21 is limited to this guide groove. It has come to be regulated by 30.

As shown in FIG. 3, this guide groove 30 has two circumferential grooves 3 at different positions in the optical axis direction.
1 and 32, and a conversion groove 33 in the optical axis direction that connects the terminal ends and starting ends of the circumferential grooves 31 and 32. Circumferential groove 31 near the camera body side
When the guide pin 25 passes through this groove, normal focusing is performed by the focusing ring 21, and this groove is called a focusing groove. Further, the circumferential groove 32 close to the copying object is such that when the guide pin 25 passes through the circumferential groove 32, the front frame 11 rotates beyond the focusing range to the close-range photographing area, and this groove is called a macro groove. In other words, the macro groove 32 extends in the circumferential direction opposite to the direction of the focusing groove 31 with respect to the conversion groove 33 .

Further, a guide groove 35 in the optical axis direction is provided in the joint ring 15, and a zooming lock body 36 is provided in this guide groove 35.
are fitted so that they can be moved in the optical axis direction while being restricted from rotation. The zooming lock body 36 has a substantially U-shaped cross section with legs 37 and 38 facing outward at the front and rear, and the front leg 37 has a circumferential groove 39 bored into the inner surface of the focusing operation ring 21. It is fitted in such a way that it can rotate freely. Therefore, the focusing operation ring 21 can freely rotate with respect to the zooming lock body 36;
1 in the optical axis direction together with the focusing operation ring 21 that moves the optical axis 1 in the optical axis direction along the conversion groove 33. A zooming lock body 3 is provided on the rear end surface of the zooming operation ring 22 when the zooming operation ring 22 is rotated to the longest focal length position.
When the focusing operation ring 21 is moved toward the object side, a zooming lock groove 40 into which the leg portion 38 is inserted is formed. Legs 38
is located at the rear end surface of the zooming operation ring 22 when the focusing operation ring 21 rotates along the focusing groove 31, and does not hinder the rotation of the zooming operation ring 22.

Therefore, in the present device having the above configuration, when the guide pin 25 is located in the focusing groove 31 of the guide groove 30 as shown in FIGS. It can be rotated freely within a range of 31 degrees. Furthermore, in this state, the legs 38 do not interfere with the rotation of the zooming operation ring 22, so focusing and zooming can be performed freely.

To perform macro photography, the focusing operation ring 21 is rotated to the shortest photographing position, that is, until the guide pin 25 is located at the end of the exchange groove 33, and the zooming operation ring 22 is further rotated to the longest focusing position. After the legs 38 of the zooming lock body 36 and the zooming lock groove 40 are opposed to each other (FIG. 2C),
Push the focusing operation ring 21 forward in the optical axis direction (FIGS. 2 and 3D). In other words, if the zooming operation ring 22 is at a position other than the longest focusing position, even if the focusing operation ring 21 is rotated to the shortest photographing position, the leg portion 38 will come into contact with the rear end surface of the zooming operation ring 22 and the front of the focusing operation ring 21 will be moved. Since movement is restricted, it is not possible to move to the macro photography area (Figure 2B). When the focusing operation ring 21 is pushed forward along the conversion groove 33, the focusing operation ring 21 can be further rotated to the close-up shooting range by the guide pin 25 and the macro groove 32, so that focusing can be performed within the range of the macro groove 32. Macro photography can be performed by rotating the operation ring 21. Furthermore, when the focusing operation ring 21 is pushed forward, the zooming lock body 36 moves in the same direction, and its legs 38 fit into the zooming lock grooves 40.
rotation is constrained. In other words, the zooming operation ring 22 is locked in the macro photography area.

To return to the normal focusing range from macro photography, the focusing operation ring 21 should be rotated to the maximum photography distance position for macro photography (the shortest photography distance for normal photography) and then pulled back. The guide pin 25 enters the focusing groove 31 from the conversion groove 33 and becomes freely rotatable for focusing within the focusing groove 31, and the leg portion 38 comes off from the zooming lock groove 40 and closes to the zooming operation ring 22.
It also becomes possible to rotate freely.

In the above embodiment, the position of the zooming lock groove 40 is determined so that macro photography can be performed at the rotational position of the zooming operation ring 22 on the long focal length side.
Depending on the focal length adjustment range of the zoom lens, the position of the zooming lock groove 40 may be determined in accordance with the rotating position of the zooming operation ring 22 on the short focal length side. Furthermore, zooming lock grooves 40 are provided corresponding to the rotational positions at both ends of the long focus and short focus.
Macro photography may be possible at both ends of zooming.

Furthermore, in the above embodiment, the focusing operation ring 2
1 is provided with a guide pin 25, and the connecting ring 15 is provided with a guide groove 30. However, since the relationship between the groove and the pin is relative, the focusing operation ring 21 is provided with a guide groove, and the connecting ring 15 is provided with a guide groove. A similar function can be obtained by providing .

As described above, according to the zoom lens of the present invention,
In so-called two-handed zoom, the zooming ring is rotated to the longest focus or shortest focus position,
In this state, macro photography can be performed simply by moving the focusing operation ring in the optical axis direction. Moreover, the main configurations required for this are: providing a conversion groove and a macro groove in the guide groove of the focusing operation ring, supporting a zooming lock body on a fixed lens barrel so as to be movable in the optical axis direction, and providing a zooming lock body on the zooming operation ring. All that is required is to provide a groove, and the only new part to be installed is the zooming lock, so there is no need for a separate helicoid for the macro mechanism or a means for switching between normal shooting and other functions like in conventional lenses of this type. A zoom lens having an extremely practical and inexpensive macro mechanism can be provided.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the zoom lens of the present invention, FIG. 2 is a longitudinal sectional view similar to FIG. 1 showing an operating state different from that in FIG. 1, and FIG.
C and D are developed views in the direction of the arrows of FIG. 1 showing the relationship between the guide groove and the guide pin and the relationship between the zooming lock body and the zooming lock groove, and show mutually different operating states. 11... Front frame, 12... Rear frame, 15... Joint ring (fixed lens barrel), 20... Helicoid, 21... Focusing operation ring, 22... Zooming operation ring,
23... Straight groove, 24... Rotation transmission pin, 25...
... Guide pin, 30 ... Guide groove, 31 ... Focusing groove, 32 ... Macro groove, 33 ... Conversion groove, 35 ... Guide groove, 36 ... Zooming lock body, 40 ... Zooming lock groove, L1 ... ...front group lens, L2...rear group lens.

Claims (1)

[Claims] 1 A zoom lens in which a fixed lens barrel rotatably supports a focusing operation ring that changes the focal position of the lens system as it rotates, and a zooming operation ring that changes the focal length of the lens system as it rotates. A guide groove for regulating the movement range of the focusing operation ring is provided on one of the fixed lens barrel and the focusing operation ring, and a guide pin that fits into the guide groove is provided on the other, and the guide groove A focusing groove in the circumferential direction corresponding to the focusing rotation range, a conversion groove continuous in the optical axis direction from the end of the focusing groove on the shortest shooting distance side, and a circumferential direction opposite to the focusing groove from the end of the conversion groove. A zooming lock body, which moves integrally with the focusing operation ring in the direction of the optical axis and is free to rotate relative to the fixed lens barrel, is further restrained from rotating. and supporting the zooming operation ring so as to be movable in the optical axis direction, and moving the focusing operation ring along the conversion groove to the macro groove end while the zooming operation ring itself is at the shortest focus position or the longest focus position. A zoom lens capable of macro photography, characterized in that it is provided with a zooming lock groove into which the zooming lock plate is inserted when the lens is rotated.