JPH0219768Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field This invention is a straight-line camera that performs zooming by sliding one operating ring in the direction of the optical axis and focusing by rotating it around the optical axis. The present invention relates to a macro switching device that can switch between normal photography and macro photography without taking your hand off the operating ring in a zoom lens.

Prior Art In a general linear zoom lens consisting of four groups: a focus lens, a variator, a compensator, and an imaging lens, in order to switch from normal photography to macro photography, one of the variator and compensator must be fixed and the other It is common practice to move the lens in the optical axis direction, or to adjust the zoom mechanism to the shortest focal length (wide end), and then extend the entire lens system further.

However, in the former case, the distance between the variator and compensator, which move while maintaining a predetermined relative relationship in normal shooting, must be changed significantly by macro switching operation, so it is necessary to move one of the two lens groups. The angle of the cam groove of the cam ring becomes unreasonable, making it difficult to move the operating member, and the cam groove requires extremely high precision.
There was a drawback that productivity was significantly impaired. moreover,
Since the distance adjustment becomes discontinuous due to macro switching, even when photographing a subject that is slightly closer than the closest position in normal shooting, it takes a lot of time to adjust the distance, and there is a risk of losing shutter stability. .

In addition, in the latter case, in addition to the helicoid mechanism for distance adjustment during normal photography, which is installed at the front end of the lens barrel, a helicoid mechanism for distance adjustment during macro photography must be installed at the rear end of the lens barrel, making the structure more complicated. As production costs rise, lens barrels become larger,
This results in weight gain. Furthermore, because the amount of movement required is small, macro photography is performed only at the shortest focal point, which results in a large reduction ratio of the subject, making it impossible to fully utilize the effects of close-up photography.

Furthermore, in any case, switching between normal photography and macro photography was normally performed using a macro switching member that was provided separately from zooming and distance adjustment, so each time switching was performed, the operation ring was changed. It is necessary to take one's hand off the lens to operate the macro switching member, which makes the operation complicated and impairs the good operability of the linear zoom lens.

Purpose This idea was made in view of the above points.
In a linear zoom lens, by setting the operation ring to the longest focal length (telephoto end), the rotation angle of the operation ring is expanded toward the short distance direction. It is an object of the present invention to provide a macro switching device for a linear zoom lens that is further extended.

Structure Therefore, the macro switching device of the linear zoom lens according to this invention rotates by sliding the operating ring in the optical axis direction, and the operating ring is attached to the outer periphery of the cam frame that moves the variator and compensator in the optical axis direction. A stopper ring that moves only when the lens moves in the optical axis direction is attached, and a stopper pin that passes through the lens barrel in the radial direction and is biased towards the center is loosely fitted into this stopper ring, and this stopper pin is integrated with the operation ring. It can be freely engaged and detached from a notch for regulating the rotation angle provided in the member, and a pin is provided on one side of the member integrated with the operation ring and the stopper ring, and a groove into which the pin is inserted is provided on the other, so that the above-mentioned position during macro photography In order to regulate the rotation angle of the operating ring, a circumferential groove is provided on the outer peripheral surface of the cam frame into which the stopper pin can fit on the longest focal length side, and the stopper pin is normally in contact with the outer peripheral surface of the cam frame. It protrudes into the rotation angle regulating notch against the biasing force, and the rotation range of the operating ring is regulated within the normal shooting distance adjustment range, and at the longest focal length (telephoto end) position, the stopper pin is moved by its own biasing force. The operating ring is fitted into the circumferential groove and removed from the notch so that the operating ring can be further rotated in a short distance direction.

Embodiments Hereinafter, embodiments of this invention will be described with reference to the accompanying drawings.

Figure 1 shows the shortest focal length (wide end) of a zoom lens barrel with a macro switching device based on this invention.
It is a longitudinal cross-sectional view of a main part showing the position, and various cross-sections, which are not necessarily the same cross-section, are shown for easy understanding.

In the figure, 1 is a fixed frame, 2 is a cam frame that is rotatably but non-slidably attached to the outer periphery of the fixed frame 1, and 3 is a cam frame that is slidable in the optical axis direction and circumferentially on the outer periphery of the cam frame 2. A stopper ring 4 is non-rotatably attached to the lens barrel, and an operating ring 4 is slidably and rotatably attached to the outermost periphery of the lens barrel.

The operation ring 4 has a keyway 4a parallel to the optical axis, and an inner ring 5 is integrally fixed on the inside thereof, and a stopper ring 3 is rotatably screwed on the inside of the inner ring 5.

As shown in FIGS. 1 and 3, the stopper ring 3 is provided with a through hole 3a, into which the first stopper pin 6 is slidably inserted in the radial direction of the lens barrel. As shown in FIGS. 2 and 3, the first stopper pin 6 is always biased toward the center by the free end of the leaf spring 7 whose base is fixed. In the illustrated state in which the operating ring 4 enters the notch 5a for regulating the rotation angle, the rotation range of the operating ring 4 is limited to the normal shooting distance adjustment range.

A second stopper pin 8 is also implanted in the inner ring 5 toward the center, and fits into the groove 3b formed in the stopper ring 3 as shown in FIG. The scope is regulated.

The cam frame 2 is provided with a circumferential groove 2b having a slope 2a at the rear on the outer periphery near the tip, and is at the longest focal length (telephoto end) position with the stopper ring 3 at the most extreme position, as shown in FIG. As shown by the line, the first
The position and depth of the circumferential groove 2b are determined such that the stopper pin 6 fits into the circumferential groove 2b and leaves the notch 5a.

The cam frame 2 also has a cam groove 2c that is implanted in the stopper ring 3 and into which a guide pin 9 that is guided by a vertical groove 1a in the optical axis direction provided in the fixed frame 1 is loosely fitted, and a first cam groove 2c that holds the variator V. The cam groove 2d is implanted on the outer periphery of the movable frame 10, into which the guide pin 11 guided in the vertical groove 1b of the fixed frame 1 is loosely fitted, and the cam groove 2d is implanted on the outer periphery of the second movable frame 12 that holds the compensator C. The guide pin 1 is guided by the vertical groove 1b.
A cam groove 2e into which 3 is loosely fitted is formed.

A focus lens FC is attached to the tip of the fixed frame 1.
A focus ring 15 that is integral with the front lens frame 14 that holds the front lens frame 14 is helicoid-coupled, and a connecting pin 16 is implanted in the rear outer circumference of the focus ring 15.
engages with the keyway 4a of the operation ring 4 and moves together in the rotational direction.

Note that M in the figure indicates only the front half of the imaging lens.

In the linear zoom lens configured as described above, when the operation ring 4 is moved straight in the optical axis direction from the wide end indicated by the solid line in FIG. The stopper ring 3 screwed to the guide pin 9 is guided by the vertical groove 1a and moves in the optical axis direction, and the cam frame 2, which loosely fits the cam groove 2c into the guide pin 9, rotates.

This allows the guide pins 11 and 13 to move into the cam groove 2.
d, 2e, the first and second moving frames 10, 1
2 move independently in the optical axis direction, zooming is performed in the direction of increasing the focal length, and when the stop ring 3 comes into contact with the flange of the fixed frame 1, the straight movement of the operation ring 4 is stopped and the telephoto end is reached. becomes.

Furthermore, when the operating ring 4 is rotated at any straight forward position other than this telephoto end, the keyway 4a is inserted into the connecting pin 16.
The focus ring 15 is rotated through the focus ring 15, and the focus lens FC, which is integrated with the focus ring 15, is rotated simultaneously, and the shooting distance is adjusted back and forth by the helicoid.As shown in Fig. 2, the rotation range is as follows. It is regulated by the first stopper pin 6 and the notch 5a of the inner ring 5.

Next, at the telephoto end position shown by the imaginary line in FIG. Since the inner ring 5 is separated from the notch 5a, the rotation range of the inner ring 5 is restricted by the second stopper pin 8 and the groove 3b, and as shown in FIG. ~1.5m), the rotation angle is automatically expanded by range b (shooting distance 1.5 to 1.0m), and the macro photography mode is entered in rotation range b.

Note that in the macro shooting state, the first stopper pin 6 is inside the part of the inner ring 5 that does not have the notch 5a, so even if you try to move the operation ring 4 backward, the first stopper pin 6 will not touch the cam frame 2. Since it cannot be separated from the circumferential groove 2b, it cannot be moved backward.

Therefore, when the operating ring 4 is returned to the normal shooting state where the first stopper pin 6 is in the range a shown in FIG. The leaf spring 7 is moved backward from the circumferential groove 2b of No. 2 along the slope 2a.
The focal length is pushed outward against the pressure, moves upward in FIG. 1, and returns to a position where it engages with the notch 5a of the inner ring 5, allowing adjustment to any desired focal length.

In the above embodiment, in order to prevent vignetting even if the focus lens is extended extra, the macro shooting state is switched only when the operating ring 4 is at the longest focal length (telephoto end) position, but this is not always the case. The present invention is not limited to this, and a circumferential groove 2b into which the first stopper pin 6 is fitted may be provided at any point or any range near the longest focal length position to enable switching to the macro photography state.

Effects As mentioned above, according to this invention, the operation ring of a linear zoom lens can be adjusted to the maximum focal length (telephoto end).
Just by positioning the stopper, the range of photographic distance adjustment is automatically expanded to the short distance side, allowing you to switch between normal photography and macro photography without taking your hand off the control ring.

In addition, the variator and compensator are kept at the longest focal length position even during macro photography, so the cam grooves that drive these lens groups are smooth, no special precision is required, and the operation ring can be operated easily. Since the distance can be adjusted continuously even during macro switching, rapid photographing is possible.

Furthermore, since macro photography is performed at the longest focal length side, the subject can be photographed larger even when the shooting distance is the same, and the effect of close-up photography can be fully demonstrated. There is no need to increase the size, the whole can be made compact, and the structure is simple and can be supplied at low cost.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of a linear zoom lens equipped with a macro switching device showing an embodiment of this invention, FIG. 3 is a sectional view taken along the - line in FIG. 2. 1...Fixed frame, 2...Cam frame, 2b...Circumferential groove, 3...Stopper ring, 3b...Groove for regulating rotation range during macro photography, 4...Operation ring, 5...
Inner ring, 5a... Notch for regulating rotation range during normal photography, 6... First stopper pin, 7... Leaf spring, 8... Second stopper pin, 10... First moving frame, 12... ...Second movement frame, 15...Focus ring.

Claims (1)

[Scope of Claim for Utility Model Registration] In a linear zoom lens that performs zooming by sliding one operating ring in the direction of the optical axis and focusing by rotating it around the optical axis, A cam frame is rotatably but non-slidably attached to the periphery of the cam frame and rotates to move the variator and compensator in the optical axis direction. A stopper ring is provided that is unrotatably mounted in the optical axis direction and moves in conjunction with the movement of the operating ring in the optical axis direction, and a stopper pin that is slidable in the radial direction of the lens barrel and biased toward the center is attached to the stopper ring. By moving the stopper pin in the radial direction,
It can be freely engaged with and detached from a rotation angle regulating notch provided in a member integrated with the operating ring, and a pin is provided in one of the member integrated with the operating ring and the stopper ring, and a groove into which the pin is inserted is provided in the other. The rotation angle of the operating ring during macro photography is regulated, and a circumferential groove is provided on the outer periphery of the cam frame into which the stopper pin can fit on the longest focal length side. The operation ring contacts the surface and protrudes into the rotation angle regulating notch against the biasing force, and the rotation range of the operation ring is limited to the normal shooting distance adjustment range, and at the longest focal length position, the stopper pin is self-adjusted. A macro switching device characterized in that the operating ring is fitted into the circumferential groove and separated from the notch by force, and can be rotated further in a short distance direction.