JPS63306431A - Lens barrel equipped with insertion filter - Google Patents

Abstract

PURPOSE:To transmit a change in F number to a camera body side automatically by obtaining one of pieces of F number information from an information means with a detection signal generated by a switch means and sending it to the camera body side. CONSTITUTION:A filter for light quantity control which has a certain characteristic exposure correction value among filters 2 is fixed to a holding frame and inserted into an optical path of photography. Switches 5a and 5b which are turned on and off by a notch or hole formed in the filter holding frame are provided on a lens barrel side and an exposure correction value in the Ev unit of the filter is read. On-off signals of those switches 5a and 5b are sent to the information means 8 such as a ROM stored with, for example, F numbers of lens systems. The ROM 8 finds an F number corrected with the exposure correction value of said signal and the current F number of a lens system to output F number information to the camera body side. Consequently, a photographing device can determines the best exposure automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique for automatically performing exposure correction when a light amount adjustment filter is used in a lens barrel.

[Conventional technology]

2. Description of the Related Art Conventionally, cameras using interchangeable lenses have been known that transmit the F-number of the interchangeable lens to the camera body.

In addition, there are reflective telephoto lenses that have an aperture mechanism, but with this type of lens, the light rays are not near the optical axis but are distributed in a donut shape, so a normal aperture mechanism using aperture blades cannot be used. The mechanism becomes complicated. Therefore, generally, an aperture mechanism is not provided, and an ND filter is inserted at the rear of the lens system to substantially change the F number and provide the aperture with a light amount adjustment function.

However, there was nothing to transmit the change in F-number when using a light intensity adjustment filter such as an ND filter to the camera side, nor could it be displayed. For this reason, when these light amount adjustment filters are used when photographing based on photometric values from an external meter, it is necessary to calculate the exposure multiple, which has the disadvantage that forgetting this will result in a photographic error.

[Problem that the invention seeks to solve]

The present invention aims to eliminate the drawbacks of the above-mentioned prior art, and provides a lens barrel equipped with an insert filter that can automatically transmit changes in F-number when using a light amount adjustment filter to the camera body. is intended to provide.

[Means for solving problems]

In order to achieve the above object, the present invention provides a lens barrel capable of performing optical ffltPl adjustment using an inserted filter, and is provided with an information means capable of outputting information representing a plurality of f-numbers and a filter holding means. The present invention is characterized in that it includes a switch means capable of detecting the exposure correction value, and a means capable of obtaining one piece of F-number information from the information means using a detection signal from the switch means and transmitting it to the camera body side.

[For production]

The operation of the present invention will be explained. A display means such as a cutout or a hole for displaying the exposure correction value of the filter in EV units is provided on the filter holding frame into which the light amount adjustment filter is inserted into the photographing optical path.

If the light amount adjustment filter is an ND filter, one filter will have one exposure compensation value, and if it is a combination of two polarizing filters, the amount of transmitted light will change by relatively changing the polarization direction. The exposure compensation value changes from

A filter having a specific exposure correction value among these is fixed to a holding frame and inserted into the photographing optical path. On the other hand, a switch that is turned on and off by a notch or hole formed in the filter holding frame is provided on the lens barrel side to read the exposure correction value in Ev units of the inserted filter.

The on/off signal of this switch is, for example, the F of the lens system.
The number is transmitted to information means such as a ROM that stores the number. The ROM calculates the corrected F-number from the exposure compensation value from this signal and the current F-number of the lens system, outputs the F-number information, and transmits it to the camera body, and the photographing device automatically sets the appropriate exposure. can be determined.

〔Example〕

Embodiments of the present invention will be described based on the drawings. 1 to 7 show an example in which the present invention is applied to a reflective telephoto lens as an embodiment.

In FIG. 1, a filter holding frame 3 is equipped with an ND filter 2 as shown in FIG. 2 behind the rear lens on the lens mount 11 side of the lens body 1 of a reflective telephoto lens.
A cutout hole 4 is formed in which the holder can be inserted and removed. As is clear from FIG. 2, the filter holding frame 3 is equipped with an ND filter 2.
Exposure correction value display groove 3a as a signal source corresponding to the brightness of.

3b is formed. The brightness of the ND filter 2 is displayed by the combination of the presence or absence of these two exposure compensation value display grooves 3a and 3b, and the exposure compensation value display grooves 3a and 3b formed in the filter holding frame 3 are connected to the lens body. This can be detected by two switch members 5a, 5b provided on side l. The specific structure of the switch members 5a and 5b is clarified in the enlarged views shown in FIGS. 4 to 7 showing the usage states of four types of ND filters having different exposure compensation values.

In FIG. 4, the switch members 5a and 5b are inserted into the set plate 10 when the filter holding frame 3 is inserted into the lens body 1, and at positions corresponding to the exposure compensation value display grooves 3a and 3b formed in the filter holding frame 3. The end portions of the switch members 5a, 5b are urged by springs 51a, 51b so as to protrude from the formed holes 7c, 7d toward the exposure correction value display devices 113a, 3b. In FIG. 3, switch members 5a, 5
ROM8.b, which serves as an information means, processes the signal and transmits it to the camera body side by turning on and off. The flexible substrate 7 is provided with a signal board 9 having an on/off detection section for the switch members 5a and 5b in the center plate 10 at one end and a contact point 9a at the other end. In FIG. 1, one end is attached to the set plate 10 where the switch members 5a and 5b are located, and the signal board 9 at the other end is attached to the lens mount 11, and can be connected to a contact point on the camera body side (not shown).

The ROM8, which serves as an information means, stores various information specific to the lens, including the F number, and signals from the camera body etc. are sent to the terminal ■ in the ROMB.
One of the plurality of stored information in the OMB is selected. That is,
By switching the input signal between H and L signals, addresses within the ROMB can be specified. The information stored in the specified address in the ROM 8 is retrieved and transmitted from the terminal 0 to the signal board 9 in order to be transmitted to the camera body. In the present invention, the ROM
When mounting a plurality of pieces of F number information in B at different addresses based on signals from contacts 7a and 7b, the corresponding F number information is output by switching the H and L signals of terminals 8a and 8b.

In the case of FIG. 4, the switch 5a enters the groove 3a and the collar 5
When the wire 2a is pressed against the flexible substrate 7 by the spring 51a, the wiring 7a is electrically connected to the ground terminal 7e.

This state is hereinafter referred to as "switch 5a on", and the opposite state in which there is no conduction is hereinafter referred to as r switch 5a off. Similarly, when the switch 5b enters the groove 3b, the wiring 7b and the ground terminal are electrically connected. This state is called "switch 5b on", and the opposite is called "r switch 5b off 1pa".

In FIG. 3, when the wiring 7a and the ground terminal 7e are electrically connected, the switch 53 is on, and when the wiring 7a and the ground terminal 7e are not electrically conductive, the switch 53 is off. A similar relationship holds between the wiring 7b, the grounding terminal 7e, and the switch 5b.When the switch 5a is turned on, the information means ROMB
An L signal is input to the terminal 8a of the switch 5a, and an H signal is input when the switch 5a is turned off. Similarly, when the switch 5b is on, an L signal is input to the ROM terminal 8b, and when it is off, an H signal is input.

In this way, switch 5a and switch 5b are turned on.

In the off state, a signal can be sent to the terminal of the ROM, and the ROM uses this signal to transmit information on the specified address, ie, the corrected F-number, to the camera body (not shown).

4 to 7 are enlarged views of the switch portion when four types of ND filters each having a different exposure correction value are used. The presence or absence of exposure correction value display grooves 3a and 3b in the filter holding frame 3 is changed depending on the exposure correction value of each ND filter. The exposure compensation value is displayed in Ev units.

Figure 4 shows the UV filter, and the exposure compensation value is OEV, so
Both exposure correction value display grooves 3a and 3b are provided. When this filter frame is inserted through the notch hole 4 of the lens barrel, the locking protrusion 3C comes into contact with the lens barrel fixing frame 6 and stops. At this position, the exposure correction value display grooves 3a and 3b are located opposite the switches 5a and 5b, respectively. The switches 5a and 5b are biased by the springs 51a and 51b and fall into the grooves 3a and 3b, and both the switches 5a and 5b are turned on. Therefore, an L signal is input to both terminals 8a and 8b of the ROM 8, which is the information means, and the address of the ROM is designated. Note that this state is the same as the state without a filter.

FIG. 5 shows an example of an ND filter in the case of an exposure multiple of 2, that is, an exposure correction value IEV. Only the exposure correction value display groove 3a is provided and the groove 3b is not provided, so the switch 5a is on and the switch 5b is off. Figure 6 shows an exposure compensation value of 22.
In the V ND filter, only the exposure compensation value display groove 3b is provided. Therefore, the switch 5a is off and the switch 5b is on.

FIG. 7 shows an ND filter with an exposure compensation value of 3 EV, and there is no groove for displaying the exposure compensation value. Therefore, switch 5a.

5b are both off.

If the F-number unique to the lens body is F8, the above can be summarized as follows.

FIGS. 8 to 12 show other embodiments, in which constituent elements corresponding to those of the previous embodiment are denoted by the same reference numerals. In this embodiment, two polarizing filters are overlapped to relatively change the direction of polarized light to change the exposure correction value.

In FIG. 8, 36 is a fixed polarizing filter, 35 is a rotating polarizing filter, and the rotating polarizing filter 35 is fitted into a rotating polarizing filter frame 37. Reference numeral 20 supports and fixes the fixed polarizing filter 36 and rotatably supports the rotating polarizing filter 35. Reference numeral 21 indicates an insert filter frame formed at the end of the insert filter frame, and holds the insert filter frame 2.0 at a predetermined position in the lens barrel. A locking protrusion 22 for locking is an operating member for changing an exposure correction value, and is rotatably supported on the insertion filter frame 20 by a central shaft 23.

FIG. 9 is a perspective view of the main parts of this device. A gear 37a is formed on the outer periphery of the rotating polarizing filter frame 37.
A gear 22a that meshes with the operating member 22 is formed. A portion of the operating member 22 protrudes outside the locking protrusion 21, that is, outside the lens barrel, and by rotating it with fingers, the direction of polarization can be changed and the exposure correction value can be changed. 24 and 25 are fixed stoppers that engage with a movable stopper 28 provided on the operating member 22 to restrict the rotation range of the operating member 22. Spherical or conical switching holes 26a to 26 are provided on the operating member 22 as exposure compensation value display means.
d is provided. This hole functions similarly to the exposure correction value display grooves 3a and 3b in the embodiment described above. When the operating member 22 rotates, the switches 5a and 5b open the switching hole 2.
6a to 26d. Then, when the switch 5a falls, the switch 5a turns on, and when the switch 5b falls, the switch 5b turns on.

In FIG. 10, when the movable stopper 28 is in contact with the fixed stopper 25, only the switch 5a falls into the switching hole 26d and the switch 5a is on, and the switch 5b does not fall into the hole, so the switch 5b is off. . Therefore, an L signal is sent to the terminal 8a of the ROM 8 in FIG. 3, and an H signal is sent to the terminal 8b.

In FIG. 11, only the switch 5b is on.

Therefore, an L signal is sent to the H1 terminal 8b of the ROM 8 at the terminal 8a.

In FIG. 12, both the switch 5a and the switch 5b are on. Therefore, L signals are sent to both terminals 8a and 8b of the ROM8. As described above, by rotating the operating member 22, it is possible to specify the address of the ROM 8 which serves as the information means, and the corrected F number can be specified on the camera body (
(not shown). - Note that although these embodiments have been described with respect to reflective telephoto lenses, they can be similarly used in refractive lens barrels.

In addition, although the ROM has been described as an example of the information means, it is also possible to
Any device may be used as long as it is configured to output number information.

〔Effect of the invention〕

With the configuration of the present invention, changes in the F number when a light amount adjustment filter is used in a lens barrel can be automatically transmitted to the camera body side.

Further, even when taking pictures based on the photometry of an external meter, there is no need for troublesome calculations of exposure multiples, which has the special effect of preventing mistakes in taking pictures.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the entire embodiment of the present invention, Fig. 2 is a perspective view of the insertion filter holding frame, Fig. 3 is a top view of the flexible substrate, and Figs. 4 to 7 are switches. FIG. 8 is a sectional view of the main part of another embodiment, FIG. 9 is a perspective view of the insertion filter holding frame, and FIGS. 10 to 12 are views showing the switching states of the switch. 1...Lens body, 2...Light amount adjustment filter, 3.
...Filter holding frame, 3 a t 3 b... Exposure correction value display groove, 5a, 5b... Switch, 6... Lens barrel fixing frame, 8... Information means. Patent applicant Minolta Camera Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 8 Figure 3C Figure 4 Figure 5 Figure 7 Figure 9 Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] In a lens barrel capable of adjusting light intensity by an inserted filter, information means capable of outputting information representing a plurality of F numbers, a switch means capable of detecting an exposure compensation value formed on a filter holding means, A lens barrel equipped with a plug-in filter, characterized by comprising means for obtaining one piece of F-number information from an information means using a detection signal from a switch means and transmitting the information to a camera body side.