JPS612138A - Exchanging lens for internal photometric type single-lens reflex camera - Google Patents

Abstract

PURPOSE:To make it possible to use the titled lens for an internal photometric type single-lens reflex camera by forming the 2nd transmission member unitedly with an aperture setting member in addition to the 1st normal transmittion member. CONSTITUTION:The 1st transmission member 6 is formed in a camera body and turned to information transmission start ready status by engaging with a transmission part 6 excited in the left direction, and when an aperture setting member 3 is rotated by a required aperture value, the 1st transmission member 6 transmits the difference of steps from the maximum opened value to the set aperture value to the 1st transmitted member 5. An iris EE display part 7 formed on the setting member 3 displays that the iris is automatically controlled when the set value is set up to an indicator 4. The 2nd transmission member 2 formed on the member 3 is to be engaged with the 2nd transmitted member 9 formed on the camera body, and when the member 3 is rotated so that the minimum aperture value scale (b) is set up to the indicator 4, the 2nd transmission member transmits the information of the minimum aperture value to the 2nd transmitted member 9. Thus, precise information can be applied within a limited space.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an interchangeable lens for a single-lens reflex camera with internal photometry, particularly a mechanism for automatically controlling the shutter speed (shutter speed EE) and a mechanism for automatically controlling the aperture (aperture EE).
This invention relates to an interchangeable lens for use in a camera equipped with.

Prior Art Conventional interchangeable lenses used in internal metering single-lens reflex cameras equipped with an aperture EE mechanism are generally equipped with a transmission member that directly transmits information about the maximum aperture value of the interchangeable lens to the camera body. there were. This is because information on the maximum aperture value of the interchangeable lens is required in order to calculate and display the aperture value that is automatically controlled on the camera body side before starting the actual narrowing down operation.

On the other hand, in the case of an internal metering single-lens reflex camera equipped with a shutter speed EE mechanism, if information about the difference in steps from the maximum aperture value of the interchangeable lens to the set aperture value is input from the interchangeable lens, the shutter speed can be automatically adjusted. It is possible to control and calculate and display the automatically controlled shutter speed before the start of the aperture operation, and therefore, an interchangeable lens is used that is equipped with only a transmission member that transmits information on the difference in the number of aperture steps. There is.

However, if you add an aperture EE mechanism to an internal metering single-lens reflex camera equipped with such a shutter speed EE mechanism and create a new camera that is capable of both shutter speed EE and aperture EE, the above Even if you use an interchangeable lens that only has a transmission member that transmits information about the difference in aperture steps, it is not possible to calculate and display the automatically controlled aperture value before the aperture operation starts, which is extremely inconvenient for camera users. becomes. This is because, as mentioned earlier in the case of an internal metering single-lens reflex camera equipped with an aperture EE mechanism, information on the maximum aperture value of the interchangeable lens is required to display the calculation. Therefore, if you think about it normally, an interchangeable lens used for an internal metering type single-lens reflex camera that is capable of both shutter speed EE and aperture EE will have a transmission member that transmits the information on the number of aperture steps and a maximum aperture value. This means that it is better to provide a transmission member for transmitting information together.

However, as can be seen from research on interchangeable lenses that have been commercially available, the maximum aperture value is not limited to lEV, but is set to various values (for example, Fl2°, Fl4), depending on the lens performance. .Fl7.F2.F2
．． 5. F2.8. F35°F4, F4.5,
F5.6, etc.), and there are many types of values. Therefore, when transmitting information about the maximum aperture value to the camera body using a transmission member, the position and protrusion amount of the transmission member must vary widely depending on the number of planned maximum aperture values. In this case, each position and amount of protrusion must be reliably identified and detected by the transmission member on the camera body side, so it is necessary to secure a large space for the position of the transmission member in the interchangeable lens, or to A large range must be given to the amount of protrusion of the member. However, with an interchangeable lens that already has a member that transmits the difference in the number of aperture steps as described above, if a transmission member that transmits the maximum aperture value based on the positional difference is additionally provided, a large space for installing it will be required on the camera body. It is often difficult in practice to ensure this in relation to ), which makes it difficult to accurately detect the positional difference by the transmission member, but even if the formation position of the transmission member shifts slightly due to manufacturing errors, it will not be possible to move the camera body to the maximum aperture value. Accurate communication becomes impossible. On the other hand, the situation is almost the same when the amount of protrusion of the transmission member is varied depending on the maximum aperture value. (In this case, it may be possible to provide the transmission member on the joint surface of the interchangeable lens to the camera body, but
If this is done, the transmission member may get in the way of an internal metering type single-lens reflex camera that does not have an aperture EE mechanism, making it impossible to attach the interchangeable lens to the camera body. ) Purpose In view of the above-mentioned circumstances, the present invention is directed to an interchangeable lens equipped with the first transmission member for the difference in the number of aperture steps, which is known for use in internal metering type single-lens reflex cameras capable of shutter speed EE. Instead of attaching a transmission member that transmits the maximum aperture value, by attaching a second transmission member that enables more accurate information transmission, this second transmission can be easily performed.
Information on the maximum open aperture value of the interchangeable lens can be obtained on the camera body side from the information transmitted by the transmission member and the information on the difference in the number of aperture steps transmitted by the first transmission member already provided. As a result, shutter speed E
It is also possible to use it with an internal metering type single-lens reflex camera that has both an E mechanism and an aperture E mechanism. It is an object of the present invention to provide an interchangeable lens that does not engage with a first transmission member and interfere with the mounting operation.

Summary The interchangeable lens of the present invention includes a first transmission member that transmits the number of aperture steps from the maximum open aperture value to the set aperture value of the lens;
and a second transmission member that transmits the minimum aperture value of the lens. As is known per se, the first transmission member is provided integrally with the aperture setting member in its circumferential direction at a constant distance from the maximum aperture scale regardless of the maximum aperture value of the lens. When the aperture setting member is rotated from the maximum aperture setting position to the desired aperture value setting position, it moves a distance corresponding to the number of aperture steps from the maximum aperture value to the set aperture value, and the aperture setting member moves to the desired aperture value setting position. 1. Information on the number of aperture stages is transmitted to the transmitted member. On the other hand, the second transmission member is also provided integrally with the aperture setting member, but is spaced apart from the minimum aperture scale in the circumferential direction of the aperture setting member by a distance that depends on the minimum aperture value of the lens. has been
When the aperture setting member is rotated to the minimum aperture value setting position, it occupies a position corresponding to the minimum aperture value of the lens and transmits information on the minimum aperture value to the second transmission member on the camera body side.

That is, in the interchangeable lens of the present invention, instead of transmitting the maximum aperture value to the camera body side, information on the minimum aperture value is transmitted to the camera body side through the second transmission member. , since there are fewer types of minimum aperture values than maximum aperture values (generally F16
°F22. (F32), there is no need to provide small positional differences unlike the transmission member for the maximum aperture value, and it is possible to obtain accurate information using a limited space. Furthermore, in the interchangeable lens of the present invention, the first and second transmission members protrude rearward in the optical axis direction from the aperture setting member, and the amount of protrusion of the second transmission member is shorter than the amount of protrusion of the first transmission member. ,
When attached to the camera body, the second transmission member does not engage with the first transmission member on the camera body side.

Embodiments First, before explaining embodiments of the present invention, the basic principle of information transmission according to the present invention will be explained using photographic calculation formulas.

Assuming that the exponent code in the photographic calculation formula (so-called Apex calculation) is subject brightness BV, film sensitivity SV, aperture value AV, and shutter speed is TV, the conditions for proper exposure are 5V-4, as is well known. -BV-AV1TV.

Cameras with internal metering and automatic exposure control use an open metering method that uses the lens's open aperture (AVo) as is, and its metering output is BV - AVo (= BV).

) is the basis of automatic exposure calculation, and in general automatic exposure control of aperture-priority shutter speed auto, the above formula is modified and one of the following two methods is adopted.

-1V=sV+(BV-AVo)-AV-1-AVo
=(SV-1-BVo)-AV-1-AV.

...(1) TV = SV-1-(BV-AVo)-(AV-AV
o ) = (SV-1-BVo) -P... (2) In the method of (1), the open aperture value (AVo) and set aperture value (AV) of the lens are determined from the attached interchangeable lens side. Two types of information are transmitted to the camera body, and in the case of method (2), the number of stops (Pl,
That is, since the amount of rotation of the aperture setting member of the interchangeable lens is transmitted to the camera body, there is only one piece of information. These two types of interchangeable lenses are the subject of the present invention.

Comparing both of the above methods, method (2) is advantageous in terms of cost because only one piece of information is transmitted, but this advantage exists only in automatic aperture-priority shutter speed control. That is, in method (2), since the information from the interchangeable lens side is only information on the setting number of steps (Pl), there is a disadvantage that it is not possible to calculate an appropriate aperture value in shutter speed priority automatic aperture control.On the other hand, (1 ) method with shutter speed priority automatic aperture control mode, fi1
Transforming the formula, AV=(SV-4-BVo-TV)-1-
The appropriate aperture can be calculated according to the arithmetic expression AVo. This is because, as explained at the beginning, information about the maximum aperture (AV o ) of the attached lens is transmitted from the interchangeable lens.

On the other hand, in the present invention, we focus on the point that P = AV = AVo, and by transforming this, AV o = AV-P,
Open aperture value AVo of the interchangeable lens attached to the camera body
Instead of installing a member that directly transmits this information to the camera body, the aperture setting member of the interchangeable lens attached to the camera body is set at a specific position during automatic aperture control, and the specific set position is set at a particular position depending on the aperture value. The real value AVC is AV, and the real value AV is the amount of rotation of the aperture setting member at that time (set number of aperture stages) Pc.
Substitute P for AV.

indirectly transmitted to the camera body, AV-(S V4
-BV o -rv) + AVc-Pc is an arithmetic formula that attempts to calculate the appropriate aperture, and the above specific position is the minimum aperture that allows automatic aperture control over the entire range from the maximum aperture value to the minimum aperture value. The value setting position is selected.

The configuration will be described below with reference to the drawings shown as an example.

Figure 1 shows one of the interchangeable lenses of the present invention, in which (1) is the interchangeable lens body, (3) is a rotatable aperture setting member, and on the outer periphery is a maximum aperture setting member. Value scale (
Aperture value scales from (a) to the minimum aperture value scale (b) are marked in sequence, and by matching one of the scales to the fixed index (4), an arbitrary aperture value can be set. (5) is the first transmission member provided in the aperture setting member (3), which is arranged at a constant interval from the maximum aperture value scale regardless of the type of lens (maximum aperture value). When the lens is attached, the first transmitting member (5) engages with the first transmitted member (6) provided on the camera body and biased to the left in each figure in FIG. 2 to transmit information. When the start ready state is reached and the aperture setting member (3) is rotated to the desired aperture value setting position (that is, the aperture setting member (3) is rotated so that the aperture scale representing the desired aperture value matches the index (4)). The first transmitting member (5) is formed so as to transmit the difference in the number of steps from the maximum opening value to the set aperture value to the first transmitted member (6). (7) is the aperture setting member (3
) This is a display that indicates that the aperture will be automatically controlled when the indicator (4) is matched with the aperture EE display located at has been done. (8) is a second transmission member provided on the aperture setting member (3), and this second transmission member (8) is engageable with a second transmitted member (9) provided on the camera body, and the aperture EE is displayed. Part (7
) In other words, only when the aperture setting member (3) is rotated to the minimum aperture value setting position where the minimum aperture value scale (b) matches the index (4), the second transmission member (8) transmits the information of the interchangeable lens. It is formed to transmit information on the minimum aperture value to the second transmitted member (9).

The tip lengths of the first transmission member (5) and second transmission member (8) formed on the aperture setting member (3) are as shown in Fig. 2 fA) fBl
fc) As shown in (T)l, the optical axis direction is different, and the first transmission member (5) is formed shorter than the second transmission member (8), and the interchangeable lens is attached to the camera. As shown in FIG. 2 (A+), the first transmitting member does not engage with the second transmitting member (9), but engages only with the first transmitted member (6), and the second transmitting member on the lens side (8) is the aperture setting member (
3) is rotated so that the aperture EE display part (7) matches the index (4), so that it engages with the second transmitted member (9).

The position of this second transmission member (8) is shown in Fig. 2 ml f
As shown in cl(I)), depending on the type of interchangeable lens (minimum aperture value), they can be formed at different positions separated by distances of 11, 42, and 13 from the minimum aperture value scale (b), respectively. be. In other words, if the lens is designed to transmit a constant reference aperture value and has a small minimum aperture value depending on the type of lens, the lens is designed to transmit an additional amount of the difference between the reference aperture value and the minimum aperture value. It is formed.

That is, as shown in the example in FIG. 2, in a lens whose minimum aperture value is F16, when the aperture is set to EE, the second transmission member (
8) is formed so that the second transmitted member (9) is moved by a length ta) in order to transmit the minimum aperture value F16.

Furthermore, as shown in FIG.
') is formed so as to move the second transmitted member (91) one more step with respect to the above-mentioned movement amount example (movement amount (b)).

Furthermore, as shown in Fig. 2 p), in the case of a lens having the smallest aperture value F32, the second transmission member (9) is further formed to move one more step (movement amount C). .

Note that the first transmitted member (6) and the second transmitted member (9) described above are connected to a calculation device for calculating the maximum aperture value provided within the camera body.

After attaching one of the interchangeable lenses having the above-described configuration to the camera body, when setting the shutter speed EE, the aperture setting member +33 is rotated to a desired aperture value setting position. For example, as shown in Figure 2 fAl, when the aperture value is set to 28, the maximum aperture value of the lens is 2 to the set aperture value F2.
, 8 to the first transmitted member (6) on the camera body side, the shutter speed EE or manual photography can be performed as in the prior art.

When performing aperture EE photography, set the desired shutter speed by operating the shutter speed setting member on the camera body side, and then rotate the aperture setting member (3) to set the aperture E.
Set the E display section (7), that is, the minimum aperture value scale (B) as the index (
4), the first transmission member (5) transmits information on the number of stages from the maximum aperture value to the minimum aperture value from the first aperture value to the minimum aperture value. While transmitting information on the number of stages to the first transmitted member (6),
The second transmission member (8) moves the second transmission member (9) by an amount corresponding to the minimum aperture value of the interchangeable lens.

(The maximum open aperture value is F2), as shown in FIG. 2 fBl, the second transmitted member (9) is moved by a length of (al).

1 above. From the second transmission member to the first transmission member. By calculating the information transmitted to the second transmission member by a calculation mechanism (mechanical or electrical) in the camera body, it is possible to obtain the maximum aperture value of the attached interchangeable lens. In E mode, the aperture value that is automatically controlled during actual photographing can be displayed before the stop-down operation starts.

The attached interchangeable lens (FIG. 2, also in the case of Di, the second transmission member 18) transmits information about the minimum aperture value of the attached interchangeable lens.

In other words, when the interchangeable lens shown in Fig. 2 (C1, that is, the minimum aperture value is F22 (the maximum aperture value is 1"2.8) is attached, the EE display section of the aperture setting member (3) When (7) matches index (4), that is, when the minimum aperture value is set, the second transmission member (8) of the interchangeable lens whose minimum aperture value is 1116 is the second transmission member (8). 2 From the reference amount (a) for moving the transmitted member (9),
Furthermore, the second transmission receiving member (9) is moved substantially extra by the difference between F22 and F16, and is formed at a position where the minimum aperture value F22 of the interchangeable lens is transmitted. Similarly, even with such different types of interchangeable lenses, the second transmitted member (8') can transmit the second transmitted member (8').
9') can transmit information about the minimum aperture value F22 of the attached interchangeable lens.

Furthermore, in the case of the interchangeable lens shown in Fig. 2+D), that is, when an interchangeable lens with a minimum aperture value of F32 (maximum aperture value F4) is attached, the aperture setting member (3) is set for the aperture EE. When set to the minimum aperture value setting position, the second transmission member (8'') of an interchangeable lens with a minimum aperture value of Fi6 moves the second transmitted member (9). From the amount fa), move the second transmission member (9〃) further by the difference between F32 or 1 and F16 so that the minimum aperture value F32 of the interchangeable lens is transmitted. As described above, even if there are different types of interchangeable lenses, the second transmitting member (8") can transmit the information to the second transmitted member (9") of the attached interchangeable lens. Information about the minimum aperture value F32 can be transmitted.

Effects As is clear from the above explanation, the interchangeable lens of the present invention has the following effects.

First of all, it has a simple structure that only includes a second transmission member in addition to the conventional first transmission member integrated with the aperture setting member, and an internal photometry system that has both a shutter speed E E mechanism and an aperture EE mechanism. Can be used with single-lens reflex cameras. Next, information on the minimum aperture value of the lens is transmitted by the second transmission member to the second transmitted member on the camera body side when the aperture setting member is rotated to the minimum aperture value setting position. Therefore, not only is automatic aperture control possible over the entire aperture range from the maximum aperture value to the minimum aperture value,
1st at aperture EE. The transmission of the two pieces of information by the second transmission member is performed at once by rotating the aperture setting member to the minimum aperture value setting position, and the operation for transmitting the information is simple. Furthermore, compared to the case of providing a transmission member that directly transmits information on the maximum aperture value of an interchangeable lens to the camera body as described as the prior art, when considering various interchangeable lenses used in combination with the camera body, Generally, the number of types of minimum aperture values is smaller than the number of types of maximum aperture values, so the positional difference according to the minimum aperture value of the second transmission member can be made large within a limited space.
Since it is possible to transmit accurate information even if there is a slight manufacturing error, the information on the difference in the number of aperture steps from the maximum open aperture value to the minimum aperture value transmitted by the first transmission member and the information transmitted by the second transmission member. According to the information on the minimum aperture value provided, it is possible to provide accurate information on the maximum aperture value.

Furthermore, like the first transmission member, the second transmission member is provided integrally with the aperture setting member, and is not provided at the joint surface of the interchangeable lens with the camera body.
The interchangeable lens of the present invention can be used without any problem even in a conventional single-lens reflex camera with internal photometry that is equipped with only a shutter speed EE mechanism.

That is, even if the interchangeable lens of the present invention is attached to such a camera, the second transmission member will not interfere with the attachment. In addition, the amount of protrusion of the second transmission member from the aperture setting member is made smaller than the amount of protrusion of the first transmission member from the aperture setting member, so that when the lens is attached to the camera body, the amount of protrusion from the aperture setting member is smaller than that of the first transmission member.
Since the second transmission member is configured to engage only with the second transmission member only when the aperture setting member is rotated to the minimum aperture value setting position, the lens When the camera body is mounted on the camera body, the first transmission member does not engage with the second transmitted member and hinder the mounting, so that the camera body can be mounted smoothly.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of one of the interchangeable lenses according to an embodiment of the present invention, and Fig. 2 is a schematic diagram showing how information is transmitted when the interchangeable lens of the embodiment is attached to a camera body. In the plan view, Fig. 2 CB+ has a minimum aperture value and a maximum aperture value of F16. In the case of an F2 lens, the aperture is set to F28, and in Figure 2 CB+, the minimum aperture value and maximum aperture value are F16. A diagram showing a state in which the minimum aperture value F16 is set for an F2 lens, and FIG. 2 CB is the minimum aperture value. The maximum aperture value is F2.8. Diagram showing the state where the minimum aperture value F22 is set in the case of an F22 lens, 2nd
Figure CB+ has a minimum aperture value of F4 and a maximum aperture value of F4.
．． FIG. 7 is a diagram showing a state in which the minimum aperture value F32 is set in the case of an F32 lens. (3)...Aperture setting member, (A)...Maximum open aperture value scale, (middle)...Minimum aperture value scale, (4)...Fixed index, (5)...First transmission member, (6)...second transmitted member, (8)...second transmitted member, (9)...second transmitted member.

Claims (1)

[Claims] 1. In an internal metering type single-lens reflex camera interchangeable lens, an aperture scale representing the aperture value from the maximum aperture value to the minimum aperture value of the lens is sequentially marked along the circumferential direction, and the desired 1 on the aperture scale is marked. an aperture setting member capable of setting an aperture value represented by an aperture scale that matches the fixed index by rotational operation around the optical axis of the lens that matches the fixed index; It is provided integrally with the aperture setting member at a certain distance from the maximum aperture value scale regardless of the aperture value, and engages with the first transmitted member on the camera body side when the lens is attached to the camera body. At the same time, when the aperture setting member is rotated from the maximum aperture setting position to the desired aperture value setting position, it moves a distance corresponding to the difference in the number of aperture steps from the maximum aperture value of the lens to the set aperture value. By doing so, the first transmitting member transmits the information on the difference in the number of aperture steps to the first transmitted member through the engagement, and the aperture setting member is provided with a first transmitting member that transmits information on the difference in the number of aperture steps to the first transmitted member, and the aperture setting member is arranged in a circumferential direction depending on the value of the minimum aperture value of the lens. is provided integrally with the aperture setting member at a position separated from the minimum aperture value scale by a distance of a second transmission member that engages with a second transmission member on the camera body side to transmit information on the minimum aperture value of the lens to the second transmission member; The member protrudes rearward in the lens optical axis direction from the aperture setting member, and the amount of protrusion of the second transmission member from the aperture setting member is set smaller than the amount of protrusion of the first transmission member from the aperture setting member, and the lens When attached to the camera body, the first transmission member engages only with the first transmitted member, and the second transmission member engages with the second transmitted member only when the aperture setting member is rotated to the minimum aperture value setting position. Interchangeable lenses configured to engage.