JPH0664279B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The camera of the present invention will be described in accordance with the following items.

A. Industrial application fields B. SUMMARY OF THE INVENTION C. Prior art D. Problems to be Solved by the Invention E. Means for Solving Problems F. Action G. Example [FIGS. 1 to 5] a. Appearance [FIGS. 1 and 2] b. Internal circuit [Fig. 3] c. Calculation of depth of field [Fig. 4] d. Calculation program [Fig. 5] EFFECTS OF THE INVENTION (A. Field of Industrial Application) The present invention relates to a camera, and more particularly to a camera that can easily achieve an aperture necessary to obtain an arbitrary depth of field.

(B. Outline of the Invention) The camera of the present invention is provided with a depth-of-field designating unit and an arithmetic circuit in order to allow a photographer to easily perform photographing with an arbitrary depth of field. The circuit is configured to calculate the aperture value necessary to obtain the designated depth of field from the focal length of the lens, the distance of the subject, and the designated depth of field. Therefore, according to the camera of the present invention, if the depth of field is specified by the depth of field specifying means, the aperture value for obtaining the depth of field is calculated by the arithmetic circuit. Taking a picture can be very easy.

(C. Prior Art) As a camera, there is a camera provided with an index (scale) indicating the depth of field with respect to the diaphragm on the outside (on the lens barrel) of the lens unit. With such a camera, for example, when the F number is "16", it is possible to shoot from infinity to 10 m without blurring, and when the F number is "22", it is possible to shoot from infinity to 9 m without blurring. Is indicated by the indicators. Therefore, according to such a camera, the near point and the far point of the depth of field centering on the subject are determined in a state where the subject is focused, and the diaphragm corresponding to the near point and the far point is set. Reading with the above index, adjusting the iris of the camera according to the read value, and taking a picture, a photograph with a desired depth of field can be obtained.

By the way, such a display of the depth of field is impossible due to the lens structure in the two-ring type camera having the focusing ring and the zooming ring separately.

In addition, with the automation of cameras, there are cameras that can be centrally controlled on the camera body side by providing a switch on the camera body side for setting various shooting conditions in addition to a shutter. By the way, if the centralized control is possible in this way, it is not necessary to display the aperture on the lens side, so it is difficult to display the aperture, and since the aperture ring of the lens is eliminated, it is possible to mechanically reduce the depth of focus. Difficult to see.

Therefore, although the camera mechanically should be able to freely increase or decrease the depth of field by making use of the diaphragm, it is not possible to take pictures using the diaphragm. That is, the automation of the camera restricts the ability of the camera to fully exhibit.

(D. Problems to be Solved by the Invention) As described above, in a conventional camera with a zoom lens that does not have a diaphragm display, the depth of field could not be confirmed. I couldn't judge if I could do it without intuition and experience.

Further, even in a camera with a diaphragm display, the display of the depth of field is due to the scale, which is very inaccurate. Even if the depth of field can be confirmed, if the depth of field is not the desired value, how to adjust the aperture to obtain the desired depth of field It can be judged only by intuition and experience whether it should be done, and it is extremely difficult for an amateur to judge.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a novel camera capable of extremely easily shooting with a desired depth of field.

(E. Means for Solving Problems) In order to solve the above problems, the camera of the present invention is provided with a depth-of-field designating means and an arithmetic circuit, and the arithmetic circuit includes a focal length of a lens and an object distance. The aperture value required for obtaining the designated depth of field is calculated from the designated depth of field.

(F. Action) According to the camera of the present invention, if the depth of field is designated by the depth of field designating means, the aperture value for obtaining the depth of field is calculated by the arithmetic circuit. By controlling the aperture automatically or manually based on the above, it is possible to obtain a state capable of shooting with the designated depth of field.

(G. Embodiment) [FIGS. 1 to 5] A camera of the present invention will be described in detail below with reference to an embodiment shown in the accompanying drawings.

1 to 5 are for explaining one example of the implementation of the camera of the present invention.

(A. Appearance) [FIGS. 1 and 2] FIGS. 1 and 2 are perspective views of the camera.

1 is a camera, 2 is a camera body, 3 is a zooming lens, 4 is a focal length control unit (zooming ring), 5 is a shutter button, 6 is a viewfinder, 7 is an aperture value setting switch, 8 is a mode selector switch, and 9a and 9b. Is a focal depth setting switch, 9a is a near point distance setting switch, and 9b is a far point distance setting switch. For example, by pushing the focal depth setting switches 9a and 9b, the near point distance switch,
The far point distance can be set.
The dials 9a and 9b may be used. 10 is a display.

(B. Internal Circuit) [FIG. 3] FIG. 3 is a block diagram showing a circuit configuration of the internal circuit.

In the figure, reference numeral 7 denotes an aperture value setting switch, which can be operated to arbitrarily set the aperture value. Specifically, when the aperture value setting switch 7 is pushed, the aperture of a certain value appears on the display 10 and the value is set as the aperture value by the operation of the arithmetic circuit described later.
Then, each time the aperture value setting switch 7 is pushed, the aperture value is switched. When the switch 7 is a dial type, the aperture value is switched by rotating the dial.

Reference numeral 8 denotes a mode change switch, which can be set to the aperture priority mode or the shutter priority mode by operating this switch. However, in this specification, the shutter priority mode and matters related thereto are not mentioned.

Reference numerals 9a and 9b denote focal depth setting switches for designating the focal depth, which are operated when changing the values of the near point and the far point displayed on the display 10 to take a picture. Operate the point distance setting switch 9a,
When changing the far point, the far point distance setting switch 9b is operated.

A photometric sensor 11 measures the amount of light from the subject side. An exposure control circuit 12 outputs a set aperture value (aperture value is preset for each light amount) corresponding to the light amount measured by the photometric sensor 11 to an arithmetic circuit 13 including a microcomputer. In the aperture priority mode, the aperture value set by the aperture value setting switch 7 is taken into the arithmetic circuit 13 prior to the aperture value from the exposure control circuit 12. A lens focal length detection circuit 14 detects the focal length of the lens 3 from the position of the zooming ring 4 and sends the focal length to the arithmetic circuit 13.

Reference numeral 15 is an AF sensor, and 16 is a distance calculation circuit that obtains the distance to the subject based on a signal from the AF sensor 15, and sends the distance to the arithmetic circuit 13.

Then, focusing is automatically performed by the output indicating the distance of the distance calculating circuit 16.

Reference numeral 17 denotes an aperture control mechanism, which controls the aperture so that the aperture value is as calculated and designated by the arithmetic circuit 13.

(C. Calculation of depth of field) [FIG. 4] FIG. 4 is a relationship diagram when the camera and the subject are shown, where l is the distance between the camera 1 and the subject 18, and l ₁ is the near point distance within the depth of focus. , L ₂ is a far point distance within the depth of focus, l ₃ is a near point side focal depth, and l ₄ is a far point side focal depth.

The near point distance l ₁ and the far point distance l ₂ which enter the depth of focus in FIG. 4 are obtained by the following equations (1) and (2).

However, in the above equations (1) and (2), δ'is the permissible circle of confusion diameter, and Fno is the F number of the camera.

(D. Arithmetic Program) [FIG. 5] FIG. 5 is a time chart showing an arithmetic program executed by the arithmetic circuit 13.

(A) "Capturing focal length f" When the program starts, first, the focal length f is detected from the position of the zooming ring 4 of the zooming lens 3 by the function of the lens focal length detecting circuit 14, and the focal length f is captured. There are some types of cameras with a lens that automatically control (zooming) the focal length and some types that perform a manual operation (operation of the zooming ring), but the present invention can be applied to any type of camera. You can

(B) “Capturing Distance 1” When step (a) is completed, the distance 1 from the camera 1 to the subject 18 which is detected by the functions of the AF sensor 15 and the distance calculating circuit 16 is captured. The present invention can also be applied to a camera of a type that focuses manually by operating the focusing ring. In such a type of camera, a focusing distance l is obtained from the position of the focusing ring, You may make it take in.

(C) “Is there a depth designation?” When step (b) is completed, the focal depth setting switch 9a,
It is determined whether or not the depth of focus is designated by the operation of 9b.

(D) "Acquisition of aperture value Fno" If the result of the determination in step (c) is "No", the aperture value Fno is captured. When the aperture value Fno is set by operating the aperture value setting switch 7, the set value is fetched as the aperture value Fno, and the aperture value Fno is set by operating the aperture value setting switch 7. If not, the aperture value preset for the amount of light measured by the photometric sensor 11 is fetched from the exposure control circuit 12.

(E) “Calculation of near point distance l _{1 within} the depth of focus” When step (d) is completed, the near point distance l ₁ within the depth of focus is calculated by the above equation (1). In the present embodiment, the permissible circle of confusion δ'of this equation (1) is set in advance as a constant. However, this value may be switched. In this case, the resolution can be switched.

(F) “Calculation of the far point distance l _{2 within} the depth of focus” When step (e) is completed, the far point distance l ₂ within the depth of focus is calculated by the above equation (2).

(G) "Show near point distance l ₁ and the far point distance l _2" step (e), the near point distance l ₁ entering the calculated depth of focus in _(f), also the far point distance l ₂ by a display 10 indicate.

Thus, the display on the display 10 (for example, the display of "1.5 m to 5 m" as shown in FIG. 1) can accurately confirm the depth of focus under the current shooting conditions.

(H) “Capturing the designated depths l ₃ and l ₄ ” When the determination result of the step (c) is “high”,
That is, the depth of focus setting switch 9a, setting the depth of focus by 9b operation if (specified) have been made fetches the focal depth l _3, l ₄ being the set. The focal depth on the starting point side set by operating the near point distance setting switch 9a and the focal depth on the far point side set by operating the far point distance setting switch 9b do not necessarily have to be equal. For example, 10m in front of the subject 18
It is also possible to photograph the subject 18 so that it is substantially in focus within a range of 25 m after the subject 18, and the depth of focus on the far point side is set to 0 and the depth of focus on the near point side is set to 10 m, for example.
You can also make settings such as This does not come into focus after the subject 8, and the subject 18 and
The focus is in front of m. On the contrary, it is possible to set the depth of focus on the near point side to 0 and the depth of focus on the far point side to, for example, 10 m. In addition, when the depth of focus is set to 0 in this way, 0 is set even without operating the setting switch (9a on the near point side and 9b on the far point side) for setting the depth of focus. You can However, it goes without saying that regardless of the depth of focus being 0, the depth of focus may not be set without operating the setting switches 9a and 9b.

(I) "Calculation of near point distance l ₁ and far point distance l ₂ " When step (h) is finished, the near point distance l ₁ and the far point distance l ₂ that enter the depth of focus are calculated. Note that l ₁ and l ₂ can be obtained by the following equations (3) and (4).

l ₁ = l-l ₃ (3) l ₂ = l + l ₄ (4) (4) "Calculation of required aperture value Fno1" When step (i) is completed, the near point distance l _{1 is changed} to The aperture value Fno1 to be satisfied is calculated. That is, determine the aperture Fno1 as l ₁ is obtained enters the depth of field. This aperture value Fno1 is calculated by the following equation (5).

The equation (5) is derived as follows.

That is, Is. Next, f ² + (l−f) δ′F around the above equation
When multiplied by no, l ₁ {f ² + (l−f) δ′Fno} = f ² l. Subtracting ^f 2 _{l 1} from both sides of this equation, the _{l 1 (l-f) δ'Fno} = f 2 (l-l 1). Dividing both sides of this equation by l ₁ (l−f) δ ′ gives Becomes Then, when the aperture value Fno for l ₁ is Fno1, the above equation (5) is obtained.

When (Le) "required aperture calculation of Fno2" step (j) is completed, and calculates an aperture value Fno2 to satisfy the far point distance l _2. That is, determine the aperture Fno2 as l ₂ is obtained enters the depth of field. This aperture value Fno2 is expressed by the following equation (6).

The equation (6) is derived as follows.

That is, Is. Then, on both sides of this equation, f ² − (lf) δ′F
When multiplied by no, l ₂ {f ² − (lf) δ′Fno} = f ² l. Subtracting 2f ² l−f ² l ₂ from both sides of this equation yields l ₂ (l−f) δ′Fno = −F ² (l−l ₂ ). Next, dividing both sides of this equation by l ₂ (l−f) δ ′ gives Becomes Then, the aperture value Fno for this l _{2 is set} to Fno ₂
Then, the above equation (6) is obtained.

(Wo) "Is the difference between Fno1 and Fno2 small?" After step (le), the two aperture values Fno1 and Fno2
It is determined whether and are substantially equal. This is because if the two aperture values Fno1 and Fno2 are significantly different, for example, if one of them is set as the aperture value Fno and the aperture value is controlled according to that value, the near point and the far point are taken. One of the points will be completely out of focus. This makes it impossible to shoot with a desired depth of field. For example, even if the camera 1 is in focus (jaspin) on the subject 1 m before, the focal depth on the near point side is tens of centimeters and the focal depth on the far point side is infinite. This occurs when the depth of field is specified. In such a case, it goes without saying that it is impossible to shoot at the designated depth unless the distance 1 in focus is changed (in this case, rather than the subject It is necessary to focus after a considerable amount of time).

Therefore, it is necessary to determine whether the aperture value Fno1 and the aperture value Fno2 are substantially equal. Then, the determination is made in step (wo). This aperture value F
It is not necessary that no1 and Fno2 be exactly the same,
Even if there is a size between them, it is possible to shoot with a depth of field that is substantially the same as desired. Therefore, it is determined whether or not the difference between Fno1 and Fno2 is smaller than a preset tolerance.

(W) "Setting of aperture value Fno" When the determination result of the above step (wo) is "high", that is, when the difference between the aperture values Fno1 and Fno2 is small, the aperture value F
Set to no. In this setting, both Fno1 and Fno2 are camera aperture division patterns (for example, 4, 2.8,
2, 1.4 ...), the aperture value is selected, and the aperture is controlled according to the value.
Controlled by 7.

When Fno1 and Fno2 are close to different aperture values in the aperture division pattern (for example, Fno1 is 2.852, Fno2
Is 3.849, and Fno1 ≈ 2.8 (one of the aperture division patterns) and Fno2 ≈ 4 (another aperture division pattern), the focus is "high". No determination result is obtained, and the setting is reset by the steps (f) to (c) described below.

(F) "Calculation of optimum distance l '" When the result of the determination in step (wo) is "No", that is, when the difference between Fno1 and Fno2 is large, an appropriate value as the distance l to the subject is obtained. That is, the calculation for obtaining the optimum distance l'is performed. That is, the distance for adjusting the focus (jaspin) is changed. The optimum distance l'is obtained by the following equation (7).

This equation (7) is derived as follows.

That is, the optimum distance l'is when Fno1 = Fno2. Therefore, the following equation is established.

On both sides of this formula Multiply by Becomes

_{Incidentally,} l 3, _{l 4} is l 'is naturally l if Kimare' determines the setting of pre _{(l 1 = l'-l 3} , l 2 = l '+
l _4).

(Yo) "Calculation of aperture value Fno when the distance is l '" When step (yo) is completed, the aperture value Fno when the distance is l'
To calculate. The aperture value Fno is calculated by the following equation (8) or (9).

The formula (8) is a formula for obtaining Fno1, and the formula (9) is Fn.
It is a formula to obtain o2 and they are equal to each other. Here, confirm that they are equal to each other.

First, the formula for obtaining Fno1 is sequentially modified.

Next, the formula for obtaining Fno2 is sequentially modified.

Then both formulas, And equal. Therefore, Fno1 = Fno2, and the aperture value may be obtained using either of the equations (8) and (9).

(T) "Setting of Aperture Value Fno" When step (Yo) is finished, the value obtained in that step (Yo) is set as the aperture value Fno, and the aperture control mechanism 17 controls the aperture value to be that value Fno. By this control, the diaphragm becomes the Fno.

(L) "Focusing so that the distance is l '" From the state where the subject 18 which is a distance l away from the camera 1 is in focus to the state where it is a distance l', or so Display a message prompting you to do so.

In this case, specifically, in a camera of a type having a focus mechanism for automatically focusing, the distance l'may be automatically focused.

Further, in the case of a camera of the type that is manually focused, for example, by flashing an arrow in the finder 6, the direction in which the focus is adjusted is specified, thereby prompting a change in the focus distance and bringing the focus to the distance l '. When the subject is in focus, it may be displayed that the subject is in focus.

With this focusing, the depth of focus setting switch 9
It becomes possible to shoot with the depth of field set by a and 9b.

According to such a camera 1, since the near point distance l ₁ that enters the depth of field and the far point distance l ₂ that enters the depth of field can be confirmed on the display 10, the displayed field of view is displayed. If you do not like the depth, you can change the shooting conditions such as changing the aperture of the camera to obtain the desired depth of field. Therefore, it is possible to take a picture with an arbitrary depth of field.

Moreover, if the depth of field near point and the depth at the far point are specified by operating the depth of focus setting switches 9a and 9b, the operation circuit 13 works to automatically obtain the depth of field. The value Fno is obtained. Further, if the desired depth of field cannot be taken unless the distance 1 for focusing is changed, the optimum distance l'is automatically calculated, and the aperture value Fno suitable for it is calculated.
Therefore, it is possible to shoot with the desired depth of field very easily.

Although the camera of the above embodiment is capable of automatically controlling the aperture, the present invention can be applied to a camera of a type in which the aperture is manually adjusted. In this case, when the aperture value Fno is calculated, the calculated aperture value Fno may be displayed on the display 10 or the finder 6 to prompt the photographer to adjust the aperture value according to the calculated value.

(H. Effects of the Invention) As is apparent from the above description, the camera of the present invention, when operated, has a depth-of-field designating unit that enters a state of designating a depth of field corresponding to the operation content. An arithmetic circuit that takes in the focal length of the lens, the distance to the subject, and the depth of field designated by the depth-of-field designation means, and calculates an aperture value for obtaining the designated depth of field. And are included.

Therefore, according to the camera of the present invention, if the depth of field is specified by the depth of field specifying means, the aperture value for obtaining the depth of field is calculated by the arithmetic circuit, and the aperture is calculated based on the calculation result. By automatically controlling or by manual operation, it is possible to take a picture with a designated depth of field.

[Brief description of drawings]

1 is a perspective view, FIG. 2 is a perspective view seen from a different angle from FIG. 1, and FIG. 3 is a circuit configuration of an internal circuit. FIG. 4 is a circuit block diagram showing FIG. 4, FIG. 4 is a relationship diagram between a camera and a subject, and FIG. 5 is a flow chart of a calculation program. DESCRIPTION OF SYMBOLS 1 ... Camera, 3 ... Lens, 9a, 9b ... Depth of field designating means, 13 ... Arithmetic circuit

Claims (1)

[Claims] 1. A depth-of-field designating unit which, when operated, enters a state of designating a depth-of-field corresponding to the content of the operation, a focal length of a lens, a distance to a subject, and the depth-of-field designation. A camera for taking in the depth of field designated by the means and performing an operation for obtaining an aperture value for obtaining the designated depth of field;