JPH0667278A - Camera with accessory discriminating function - Google Patents

Abstract

PURPOSE:To easily discriminate accessories fitted to a photographic lens and to evade inconvenience by providing identifying means on each accessory of different kind, and receiving the identifying signal of the accessories fitted to the photographic lens so as to discriminate the kind of the accessory. CONSTITUTION:For instance, when a filter 25 is fitted to the photographic lens 13 to which the accessory is not fitted, the top end supporting part 22a of a contact member 22 is pushed by a distance corresponding to the position of the rear end part 28 of the filter 25 against a compression spring 24. In other words, a contact brush 22b is slid with respect to a resistor 21 to change the position of the contact brush 22b, and a resistance value corresponding to the position is outputted to an accessory discriminating means in a microcomputer. Then, the accessory discriminating means executes a prescribed calculation based on the resistance value to judge whether the fitted accessory is the filter 25 or not. When a judgment as the filter 25 is obtained, an exposure corresponding to the filter 25 is corrected by a means for dealing with correspondence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a function of discriminating the type of accessory attached to a taking lens.

[0002]

2. Description of the Related Art Conventionally, an accessory for a taking lens of a camera is simply mounted on a front end portion of the taking lens via a mounting means. For this reason, it is not possible for the camera to recognize what kind of accessory is attached to the taking lens. For example, even if a filter is attached, shooting is performed without correcting the exposure value, or after shooting with another person. When using the same camera, there are cases where inconveniences occur, such as shooting without checking whether or not an accessory is attached to the shooting lens, and shooting with an unexpected composition.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a camera capable of discriminating the type of an accessory mounted on a taking lens.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention, which achieves the above object, provides a photographing lens to which different kinds of accessories are attachable / detachable, an identification means provided in each of the different kinds of accessories, and an identification means included in the accessory attached to the photographing lens. It is characterized by having a signal output means for outputting an identification signal based on the identification signal, and a discrimination means for receiving the identification signal from the signal output means and discriminating the kind of the attached accessory.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 5 is a perspective view showing a camera to which the present invention is applied. The camera body 12 of the camera 11 has a taking lens 13 in the front part thereof, and has a back cover 14 which can be opened and closed in the rear part. A grip portion 15 having a shutter button 16 on the upper surface is provided on one side of the camera body 12, and a liquid crystal display section 41 is provided on the upper surface of the other side.

The taking lens 13 is, as shown in FIG.
Female screw 1 with a built-in lens 17 and formed at the front end of the inner peripheral surface
Have nine. Further, on the inner circumference of the taking lens 13, there is provided an annular support protrusion 20 which is located behind the female screw 19 and is formed to project toward the center of the optical axis of the taking lens 13, and behind the annular support protrusion 20 there is an taking lens. A resistor 21 that is long in the front-back direction of the optical axis 13 is provided.

The tip end support portion 22a of the contact member 22 is slidably supported in the support groove 20a of the annular support projection 20 so as to be movable in the front-rear direction. The contact point member 22 slidably contacts the contact point brush 22b with the resistor 21, and the tip end support portion 22a is attached to, for example, the wall portion 2 of the filter 25.
A compression spring 24 urges it forward so that it is pressed against 8a. The compression spring 24 is used for the photographing lens 1.
3, the spring pad 34 and the contact member 22 that are formed to project toward the inner peripheral side
It has been reduced to between.

The resistor 21 and the contact member 22 constitute a resistance value reading device (signal output means).
A resistance value (identification signal) corresponding to the position of the contact brush 22b that is in sliding contact with is output to the accessory discriminating means 31 in the microcomputer 30 (FIG. 5).

The accessory discriminating means 31 executes a predetermined calculation based on the input resistance value, and the photographing lens 13
Discriminates the type of accessory attached to the front end of the. The microcomputer (hereinafter referred to as “microcomputer”) 30 further has a coping means 32. Based on the discrimination result by the accessory discriminating means 31, for example, when the attached accessory is a filter, the response processing means 32 corrects the exposure value accordingly, and when the accessory is a lens hood, the corresponding lens hood is The fact that it is attached is displayed on the liquid crystal display unit 41 (FIG. 5) to inform the photographer.

As shown in FIG. 1, the filter 25 is
It has a filter body 27 fitted in the inner circumferential groove 26 and a male screw 29 formed on the outer circumferential surface of the rear end portion 28. The length of the rear end portion 28, that is, the wall portion (identification means), is such that when the male screw 29 is completely screwed into the female screw 19, the front end support portion 22a of the contact member 22 is pushed rearward of the optical axis by a predetermined amount. ) The contact position of 28a with respect to the tip support portion 22a is determined.

Further, as shown in FIG. 2, the lens hood 40 has a male screw 29, which is the same as the filter 25, formed on the outer peripheral surface of the rear end 28 ', and the wall of the rear end 28' (identifying means). ) 28'a is configured so that the contact position with the front end support portion 22a when the lens hood 40 is completely screwed into the female screw 19 is located a predetermined amount forward of the filter 25. . Therefore, since the contact member 22 is located on the front side as compared with when the filter 25 is attached,
A resistance value different from that of the filter 25 is output. In this way, by changing the shape of the portion corresponding to the rear end portion 28 for each accessory, it is possible to configure a plurality of accessories that can output a resistance value according to the type.
O in the figure indicates the optical axis of the taking lens 13.

The operation of the camera 11 having the above-described structure is divided into a case where the camera 11 is a camera of a photometric system other than TTL such as a lens shutter type and a case of a single-lens reflex camera of the TTL photometric system. explain.

First, a case where the camera 11 is of a lens shutter type other than the TTL photometric type will be described with reference to the flowchart of FIG. That is, for example, the filter 25 is attached to the taking lens 13 in which no accessory is attached.
Is mounted by completely screwing the male screw 29 into the female screw 19, the tip end support portion 22a of the contact point member 22 resists the compression spring 24 and is moved by a distance corresponding to the position of the wall portion 28a of the rear end portion 28. Pushed backwards. Then, the contact brush 22b slides on the resistor 21 to change its position, and outputs the resistance value corresponding to this position toward the accessory discriminating means 31 in the microcomputer 30.

As a result, the accessory discriminating means 31 is
A predetermined calculation is executed based on the input resistance value, and it is determined whether or not the accessory attached to the front end of the taking lens 13 is the filter 25 (step S1). If it is determined that the attached accessory is the filter 25, the countermeasure processing unit 32 executes the exposure correction that should correspond to the filter 25 (S2). This exposure correction is intended to match the difference between the exposure value based on the photometric system and the actual exposure value, which is caused by the camera 11 having the lens shutter system and the photometric system having a configuration different from that of the photographing optical system. Done.

In S1, the accessory is the filter 25.
If it is determined that the accessory is not the lens hood 40, or if the corresponding action in S2 is completed, the process proceeds to S3 and it is determined whether the accessory is the lens hood 40. As a result, if it is the lens hood 40, the corresponding treatment means 32 causes the liquid crystal display unit 41 to “recognize the strobe irradiation angle and the photographing field angle”.
And a message prompting "vignetting prevention" is displayed (S4,
S5).

If it is determined in S3 that the accessory is not the lens hood 40, or if the corresponding measures in S4 and S5 are completed, the process proceeds to S6 and it is determined whether the accessory is a front conversion lens.
As a result, if it is determined that the conversion lens is a front conversion lens, the corresponding treatment unit 32 changes the magnification of the finder optical system and corrects the difference in the angle of view between the taking lens 13 and the finder optical system due to the mounting of the conversion lens. Yes (S7).

If it is determined in S6 that the attached accessory is not the front conversion lens, or if the corresponding procedure in S7 is completed, the process proceeds to S8 and it is determined whether or not the accessory is a reverse adapter. Then, if the device is a reverse adapter, the corresponding treatment means 32 inputs information on the photographing lens mounted in the reverse state into the microcomputer 30 (S9).

If it is determined in S8 that the attached accessory is not the reverse adapter, or if the procedure in S9 is completed, the process proceeds to S10, and it is determined whether or not the accessory is a close-up lens. If it is determined that the lens is a close-up lens, the handling means 32 switches to a dedicated shooting mode corresponding to the close-up lens (S11). By switching to this photographing mode, the correction of the photographing lens 13 and the viewfinder parallax is executed. If it is determined in S10 that the accessory is not a close-up lens, or S
When the treatment in 11 is finished, all the processes are finished.

On the other hand, the case where the camera 11 is a single-lens reflex camera of the TTL photometric system will be described with reference to the flowchart of FIG. In S12, when it is determined that the lens hood 40 is attached to the taking lens 13, the countermeasure means 32 prompts the liquid crystal display unit 41 to "recognize the strobe irradiation angle and the taking angle of view" and "prevent vignetting". Is displayed (S13, S14).

If it is determined in S12 that the accessory is not the lens hood 40, or if the corresponding measures in S13 and S14 have been completed, it is determined in S15 whether the accessory is a front conversion lens. As a result, if it is determined that the lens is a front conversion lens, the coping treatment means 32 calculates a synthetic F value and a synthetic focal length due to mounting of this lens, and stores them in the memory of the microcomputer 30 (S16).

If it is determined in S15 that the accessory is not a front conversion lens, or S16
When the coping process in step S3 is completed, the process proceeds to step S17, and it is determined whether the accessory is a reverse adapter. If it is determined that the camera is the reverse adapter, the handling means 32 determines which of the automatic exposure mode, the shutter priority mode, and the program mode is set on the camera side, and one of these modes is selected. If it is set, the mode is switched to the aperture priority mode (S19). If it is determined in S18 that neither mode is set, that is, if it is determined to be manual, no action is taken and the process directly proceeds to S20.

If it is determined in S17 that the accessory is not the reverse adapter, or if the procedure in S19 is completed, the process proceeds to S20, in which it is determined whether the accessory is a close-up lens. As a result, if the lens is a close-up lens, the corresponding treatment means 32
However, it switches to a dedicated shooting mode corresponding to the close-up lens (S21). If it is determined in S20 that the accessory is not a close-up lens, or if the procedure in S21 is completed, the entire process is completed.

Another embodiment will be described with reference to FIG. In this embodiment, the accessory 37 is of a bayonet type instead of a screw type, and a plurality of accessory side contacts 39 arranged at predetermined intervals are provided on the outer peripheral surface of the rear end portion 38 of the accessory 37. . This accessory side contact 39
The contact spacing and shape are determined so that the contact state of the lens side contact 36 when the accessory 37 is completely attached to the front end portion 35 is different between the accessories of different types. On the inner peripheral surface of the front end portion 35 of the taking lens 13, the contact 37 is provided at a position corresponding to the accessory side contact 39 when the accessory 37 is attached to the front end portion 35.
The plurality of lens side contacts 36 connected to the lens 9 are provided. The lens side contact 36 and the accessory side contact 3
A signal output means is constituted by 9.

Therefore, the front end portion 35 of the taking lens 13 is
When the accessory 37 is completely attached to the lens side contact 3
6, the accessory side contact 39 is properly connected, whereby the identification signal corresponding to the accessory 37 is output to the accessory discriminating means 31 and the same control as in the first embodiment is performed.

Still another embodiment will be described with reference to FIG.
Also in this embodiment, the accessory 42 is of the bayonet type instead of the screw type.
An engagement notch 43 is formed at the rear end portion. The engagement notch 43 is for rotating the engagement member 44 that interlocks with the contact brush of the resistance value reading device when the accessory 42 is completely attached to the front end portion 35, and has a shape for each different accessory. By changing, the rotational movement angle of the engaging member 44 can be made different, and the resistance value (identification signal) corresponding to various accessories can be output to the accessory discriminating means 31.

Therefore, the front end portion 35 of the taking lens 13 is
When the accessory 42 is attached to the accessory 4, the engaging member 44 is rotationally moved by a predetermined amount by the engaging notch 43 formed corresponding to each accessory.
The identification signal corresponding to No. 7 is output to the accessory discriminating means 31 and the same control as in the first embodiment is performed.

[0027]

As described above, according to the present invention, it is possible to easily discriminate the type of accessory to be attached to the taking lens. Therefore, even if the filter is attached, the image is taken without correcting the exposure value. It is possible to avoid inconveniences such as taking a picture with an unintended composition without noticing that the close-up lens is attached.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a first embodiment of a camera having an accessory discrimination function according to the present invention.

FIG. 2 is a cross-sectional view when an accessory different from that of FIG. 1 of the embodiment is attached.

3 and 4 are flowcharts showing the operation of the first embodiment.

FIG. 5 is a perspective view showing an entire camera having an accessory discriminating function according to the present invention.

FIG. 6 is a perspective view showing a main part of a second embodiment of a camera having an accessory discrimination function according to the present invention.

FIG. 7 is a perspective view showing a main part of a third embodiment of a camera having an accessory discrimination function according to the present invention.

[Explanation of symbols]

 11 camera 12 camera body 13 taking lens 17 lens 19 female screw 20 annular support protrusion 20a support groove 21 resistor 22 contact member 22a tip support 22b contact brush 24 compression spring 25 filter 27 filter body 28 28 'rear end 28a 28'a Wall part 29 Male screw 30 Microcomputer 31 Accessory discrimination means 32 Corresponding treatment means 35 Front end part 36 Lens side contact point 37 42 Accessory 39 Accessory side contact point 40 Lens hood 41 Liquid crystal display section 43 Engagement notch 44 Engagement member

Claims (1)

[Claims] 1. A taking lens to which different kinds of accessories are attachable / detachable; an identifying means provided to each of different kinds of accessories; a signal output means for outputting an identifying signal based on the identifying means included in the accessory attached to the taking lens. A camera having an accessory discriminating function, the discriminating means for discriminating the kind of the attached accessory upon receiving the discriminating signal from the signal outputting means.