JPH0545702A - Camera capable of enlarging short distance photographing range - Google Patents

Abstract

PURPOSE:To enlarge a range where short distance photographing can be executed by an autofocusing device as large as possible in accordance with a stop value at the time of photographing, the sensitivity value of a film and the focal distance of a photographing lens. CONSTITUTION:By depressing a shutter release member 9 to a 1st stage, a CPU 1 allows a photometry means consisting of a photometric device 5 and a photometric light receiving part 5a to measure the brightness of field, and allows an automatic range-finding device 3 to measure a distance to an object, then it receives the respective data. The CPU 1 calculates an appropriate stop value based on the photometry data and ISO data detected by a film sensitivity value detection means 6. A short distance warning decision means in the CPU 1 calculates the depth of field based on the appropriate stop value, and changes and sets a short distance warning point showing the limit of the short distance photographing by the device 3 in accordance with the depth of field. When a short distance warning decision means decides that the data obtained by the range-finding by the device 3 shows that it is at a shorter distance than the warning point, a short distance warning means 4 is fickered to inform that autofocusing is impossible. variable power system photographing optical system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a camera capable of enlarging the image-capturing range when photographing at a close range.

[0002]

2. Description of the Related Art For example, an infinite distance (hereinafter, "∞ distance")
Abbreviated as ") to a range of about 70 cm as a shooting range (hereinafter referred to as" normal shooting range ")
When shooting an object located at a close range of less than 70 cm, it is necessary to reset the shooting conditions from the conditions in the normal shooting range to the conditions suitable for macro shooting.

For example, Japanese Utility Model Laid-Open No. 64-15225 (hereinafter referred to as "first conventional example") discloses a program shutter type autofocus camera for expanding a macro photographing area without deteriorating optical performance. There is disclosed a technique designed so that the aperture value setting operation during macro photography is different from the aperture value setting operation in the normal photography range.

That is, in the first conventional example, only the luminous flux in the central region of the photographing optical system is used by forcibly setting the aperture value of the photographing optical system at the time of macro photographing to a small aperture not larger than a predetermined value. Thus, the deterioration of the optical performance in the macro shooting area is prevented.

Further, Japanese Utility Model Laid-Open No. 64-19924 (hereinafter, referred to as "second conventional example") discloses a flash shutter type program shutter type camera capable of stroboscopic photography, and strobes in a normal photographing range during macro photography. There is disclosed a technique in which the low-luminance emission level of is corrected to the low-luminance emission level at the time of macro photography to maintain an appropriate exposure value.

That is, in the second conventional example, the decrease in the effective F value of the photographing optical system during macro photographing is corrected by changing the low-luminance emission level of the strobe.

Such a problem also exists in the case of the depth of field during macro photography. For example, in a camera equipped with an automatic distance measuring device (hereinafter, simply referred to as “AF”), the shooting limit on the short distance side is generally determined by the depth of field of the photographing optical system and the distance measuring accuracy of the automatic distance measuring device. I try to make decisions based on relationships.

In this case, the depth of field is determined by assuming a case of an open F value so that a specified depth can be ensured regardless of which aperture value is used for photographing, and moreover, the depth of field of the film to be used is determined. Sensitivity is also general sensitivity (eg ISO sensitivity 10
Since it is usually calculated with 0) as a standard, when shooting with a camera designed in this way,
The user can always shoot only within the shooting range based on the depth of field on the short distance side at the open F value.

For example, focal length f = 35 mm, F at open
= 3.2, with a camera equipped with a photographic optical system with a minimum circle of confusion = 45 μm, it is assumed that the normal shooting range is from ∞ distance to 70 cm, and the lens stop position is set to a position equivalent to 70 cm. Then, since the subject depth on the front side (short-distance side) of this photographing optical system becomes 5.3 cm, the position of the close-distance warning point at the open F value is 70 cm-5.3 cm =, as shown in FIG. This is 64.7 cm, and the range that can be captured by this camera is the area from the ∞ distance to 64.7 cm.

[0010]

However, in actual photography, when the subject is bright or when a film having a high ISO sensitivity is used, the F-number (a small aperture diameter) much larger than the open F-number is used. ) Will be used for shooting, so in such shooting, the shooting range on the short-distance side will be expanded by the amount of narrowing down.

However, in the conventional camera, despite such an extremely advantageous state for the user, it has not been actively used.

The present invention has been made in view of such circumstances, and it is possible to expand the short-distance photographing range in which the maximum photographing range can be set under the photographing conditions or the brightness of the subject at that time. The purpose is to provide a camera.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to make the aperture value at the time of photographing smaller than the aperture value at the time of opening in a camera having automatic distance measuring means, exposure calculating means or flashmatic means. Possible exposure element value information (eg, proper aperture value information from the exposure calculation means, proper aperture value information at the time of flash photography formed by the flashmatic means, film sensitivity value information from the DX code reading means, from the photographing optical system Based on the focal length information of the camera and the open F-number information of the photographing optical system at that time), the limit value of the automatic distance measuring means on the short distance side is changed to a value according to the aperture value at the time of photographing. It was realized by using.

[0014]

The camera having the above-mentioned structure capable of expanding the short-distance photographing range has the automatic distance measuring means, the exposure calculating means or the flashmatic means, and the brightness of the object, the film sensitivity value, the focal length, and the opening F _{Based on} the aperture value at the time of shooting, which is determined by the exposure element value information such as _NO , or the aperture value at the time of shooting, which is determined by the flashmatic means, the short-distance warning determination means determines that the short-distance side object at that time The depth of field is calculated, and the photographing limit value on the short distance side of the automatic distance measuring means is changed and set, and the distance measurement data measured by the automatic distance measuring means is closer than the photographing limit value. If it is determined that the short distance warning is issued.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A camera capable of expanding a short-distance photographing range according to the present invention will be described in detail below with reference to an embodiment shown in the drawings.

FIG. 1 is a block diagram of an embodiment of a camera capable of expanding a short-distance photographing range according to the present invention.

Reference numeral 1 denotes a control CPU (hereinafter simply referred to as "CPU") which controls the entire control of this camera (not shown).
Then, various controls such as photometry control such as shooting sequence control, distance measurement control, automatic exposure control, flashmatic control, display control, and warning control, and exposure calculation, A / D conversion,
It is configured to perform various operations such as time measurement and short distance warning determination.

Reference numeral 2 designates a variable magnification type photographing optical system such as a zoom lens fixedly mounted on this camera. As a matter of course, the focal point at that time depends on the difference in the amount of displacement on the optical axis of the variable magnification system. The distance and the effective F _NO are changed, and the focusing is performed by the displacement of the focusing system.

Reference numeral 3 denotes a triangulation type automatic distance measuring device (hereinafter, simply referred to as "AF device") provided in this camera, for example, an infrared light emitting source such as an infrared LED and a projection arranged in front thereof. Infrared light projecting section 3 composed of an optical system
a, for example, a one-dimensional semiconductor position detecting element (PSD: P
osition Sensitive Detector) and a distance-measuring light-receiving unit 3b composed of a light-receiving optical system arranged in front of it.

In the AF device 3, the infrared light projecting section 3a is first provided.
Infrared of a required wavelength is projected from the target toward the target (subject), the infrared reflected from the target is imaged as a light spot on the light receiving surface of the one-dimensional semiconductor position detecting element of the distance measuring light receiving unit 3b, and the reference The distance from the point to the image forming light point is detected, and the detected distance data is output to the CPU 1 as the object distance (L) equivalent value (analog value).

In this case, the CPU 1 A / D-converts the input object distance (L) equivalent value to calculate 1 / L data, and based on this 1 / L data, the distance (L) to the target object. Distance is automatically measured, and the amount of movement of the focusing system of the photographing optical system corresponding to the photographing distance at that time is automatically set based on this 1 / L data. Processing is performed so that the stop position (lens stop position) of the focusing system of the photographing optical system is automatically set to a point exceeding the predetermined limit value 1 / L _lim .

Reference numeral 4 denotes, for example, a short-distance warning means configured to also serve as display means for the AF monitor, which is used when the subject is located outside the allowed photographing range (that is, 1 / L at that time). When the data exceeds the limit value 1 / L _lim ), the state can be warned by a visual or auditory action based on a command from a short-distance warning determination means (not shown) in the CPU 1. Is configured.

The visual or audible warning action in this case may be, for example, a display alert using blinking light emission of an LED or a sounding alert using sound, and as a means for performing the alert action, A case where a dedicated warning means is specially provided for this purpose, a case where a means installed to perform other functions, for example, a case where a display means for AF monitor is used, and the like are considered.

The above-mentioned limit value 1 / L _lim is set as the short-distance side photographing limit distance at the wide-angle end (hereinafter referred to as "short-distance warning point"). It is decided based on such an idea.

For example, the taking optical system 2 has a focal length f = 1.
05 mm, aperture adjustment range F _NO = 3.2 to 22, permissible circle of confusion diameter δ ′ = 45 μm, shooting distance when the focusing system is extended to the maximum (stop position of the focusing system) u = 70 cm Conventional open F _NO
The depth of field on the short-distance side obtained by the setting method with the value as the reference is

[0026]

[Equation 1] It is calculated by the following formula. As a result, as shown in FIG. 4 described above, the depth of field on the short distance side is 5.3 cm, and the short distance warning point at this time is 64.7 cm.

Therefore, in the case of designing the camera by the conventional setting method, this position must be the stop position of the focusing system, so that the value of 1 / L is 1 / 0.64.
It is necessary to set to 7 and issue a warning of the close-range shooting limit at this position, and also to release lock.

However, as described in the section of the prior art, in the actual photographing, the photographing is not always performed at the open F _NO value. Therefore, in the present invention, the photometric operation is performed before the short-distance warning point is set. Furthermore, taking into consideration the film sensitivity value determination result, the appropriate aperture value for shooting at that time is calculated, and the calculation of the depth of field on the short distance side based on this aperture value is executed. It is configured to set a short-distance warning point by.

Further, in the case of a camera equipped with the variable magnification type photographing optical system 2 as in the illustrated embodiment or a camera equipped with an interchangeable lens, the aperture F which changes at wide angle and at telephoto
_In consideration of the difference in _NO value and focal length, the depth of field on the short distance side is calculated, and the short distance warning point is set based on the calculation result.

On the other hand, in a camera configured to perform flash photography using the flashmatic method, the depth of field on the near side is calculated based on the aperture value determined by the flashmatic method. , A short-distance warning point is set based on the calculation result.

As described above, regardless of the calculation result in any case, the appropriate aperture value at that time is, for example, F _NO = 22.
If so, the depth of field on the near side is 25.3.
Since the distance is cm, the short-distance warning point should be set to 44.7 cm.

That is, in the illustrated embodiment, the short-distance warning point is 64.7 cm or more depending on the set aperture value at each time.
It will vary between 44.7 cm.

Reference numeral 5 is a photometric device provided in this camera.
The photometric light receiving portion 5a is formed of, for example, a two-divided CdS element so as to detect a backlit state, detects the brightness of the central portion and the peripheral portion of the field, and outputs the respective photometric data (analog value). It is configured to output to the exposure calculation means in the CPU 1.

In this case, the exposure calculation means in the CPU 1 A / D-converts the input photometric data to calculate appropriate EV data (appropriate exposure amount), and based on this data, an appropriate aperture value and / or Alternatively, processing is performed so that the shutter opening / closing time of the shutter control unit 7 is set.

Reference numeral 6 denotes a film sensitivity value detecting means as a DX code reading means for detecting the sensitivity value of the film used, which is a DX formed on the outer peripheral surface of a film cartridge (not shown) loaded in the camera 1. The film sensitivity value (ISO sensitivity value) is detected by detecting the code (information pattern) in a 4-bit format, for example.

Reference numeral 7 denotes a shutter control unit for opening and closing a shutter blade that also serves as a diaphragm blade by pulse driving, for example, a CPU.
The opening / closing operation of the shutter blades (not shown) is controlled based on the shutter opening / closing time from the automatic exposure control means in 1.

The shutter control section 7 controls the film sensitivity value detection means 6 to control the DX code reading result to CP when the back cover (not shown) of the camera is closed.
The exposure calculation means in U1 can be serially transmitted. In this case, the exposure calculation means in the CPU 1 determines the film sensitivity value from the transmitted DX code and corrects the shutter opening / closing time and aperture.

Reference numeral 8 denotes a variable power position detecting means for detecting the variable power position of the photographic optical system 2. For example, the amount of displacement on the optical axis of the variable power system described above is detected as an electric resistance value, and this is detected as a voltage. It is configured to be converted into data and output to the CPU 1.

In this case, in the CPU 1, the input voltage data is A / D converted to determine the position of the variable power system at that time, and the obtained variable power position and the reference variable power position. (For example, the position of the open F _NO at the wide-angle end) is obtained, and the shutter opening / closing time (or aperture) is corrected based on the result.

Reference numeral 9 denotes a shutter release member which is constructed so as to be capable of two-step stroke operation, and the first-step stroke operation starts the photometric operation / distance-measuring operation / extending operation of the photographing optical system. The shutter driving operation can be started by the stroke operation.

Next, the operation or action of the camera configured as described above and capable of expanding the short-distance shooting range will be described with reference to the flowchart shown in FIG.

S1 First, a film cartridge (not shown) is loaded in the camera, and then the back cover of the camera is closed.

Then, the CPU 1 controls the film sensitivity value detecting means 6 to read the DX code from the film cartridge and serially transmit the result to the exposing means in the CPU 1. Then, in the CPU 1, the transmitted DX
The shutter control unit 7 determines the film sensitivity value from the code.
The shutter opening / closing time (and / or aperture value) is corrected.

S2 In this state, the stroke operation of the first step of the shutter release member 9 is executed.

S3 When the first stroke operation of the shutter release member 9 is performed, the CPU 1 issues a command to start the photometric operation and controls the photometric device 5 to perform the photometric operation of the brightness of the field at that time. To do.

S4 Subsequently, the CPU 1 issues a command to start the distance measuring operation and controls the AF device 3 to execute the distance measuring operation of the photographing distance at that time. However, at this point, the AF monitor display means (which is also a short-distance warning means) 4 is still kept in the off state.

S5 As a result of these photometric and distance measuring operations, the respective measured values are input to the CPU 1,
The exposure calculation means in the CPU 1 calculates the appropriate EV value at that time to determine the aperture value at the time of shooting. Then CPU1
The short-distance warning determination means in the above sets a short-distance warning point (which is also the limit value 1 / L _lim ) corresponding to the aperture value.

S6 Subsequently, the short distance warning determination means in the CPU 1 compares 1 / L corresponding to the photographing distance at this time with the limit value 1 / L _lim corresponding to the aperture value at this time.

S7 At this time, if the subject is located on the side close to the camera beyond this short distance warning point (1
/ L is located at a close point _{exceeding the} limit value 1 / L _lim ), the short-distance warning determination means in the CPU 1 is
For the short-distance warning means 4 which is also a monitor display means,
For example, a command is issued to issue a warning by blinking display.

S8 Therefore, the short-distance warning means 4 continues the blinking display operation for the entire duration of the first stroke operation of the shutter release member 9 by the user.

S9 When the user stops the first-step stroke operation of the shutter release member 9, the CPU
The short-distance warning means No. 1 controls the short-distance warning means 4 to stop the blinking display operation of the short-distance warning means 4 and shift the camera to the hibernation state at this time.

S10 Now, as a result of the comparison in the step S6,
When the subject is located on the ∞ side of this short distance warning point (when 1 / L is less than the limit value 1 / L _lim ), the CPU 1 controls the variable magnification photographing optical system. The system 2 is instructed to execute the payout operation of the focusing system. Therefore, the variable magnification photographing optical system 2 displaces the focusing system to the focusing position according to the photographing distance at that time.

S11 Subsequently, the CPU 1 turns on the short-distance warning means (hereinafter also referred to as "display means") 4 which is also the display means for the AF monitor, and indicates to the user that the subject is within the photographing range. Control to notify.

The user at S12 selects whether or not to perform photographing in this state.

S13 If the photographing is stopped here (the first step stroke operation of the shutter release member 9 is stopped), the CPU 1 turns off the display means 4 and shifts the camera to the rest state. To control.

On the other hand, when the user thinks that the user wants to take an image in the step of S12, the second step stroke operation of the shutter release member 9 is executed as it is.

S15 When the second stroke operation of the shutter release member 9 is performed, the CPU 1 causes the display means 4
Control to turn off.

S16 Subsequently, the automatic exposure control means in the CPU 1 issues a command to the shutter control section 7 to correct the aperture value corrected by the film sensitivity value (including the focal length and the opening F _NO if necessary). Also, the shutter is controlled to open and close according to the shutter open / close time.

S17 Subsequently, the CPU 1 controls so that the focusing system of the photographing optical system 2 which has been displaced for focusing is returned to the start position.

S18 After that, the CPU 1 winds a film (not shown) in accordance with the photographing sequence, and further controls the camera so as to shift to the rest state at the end of the winding, thus ending a series of operations.

In the illustrated embodiment, the case of shooting with the aperture value based on the proper EV value determined on the basis of the brightness of the subject is described, but the natural light shooting mode and the flash light shooting mode are selected. In a camera that can be selected by means, when the flash photography mode is selected and the flash photography is performed by the flashmatic method, this flowchart is read again based on the aperture value determined by the flashmatic method. And

Although one embodiment has been described above, the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

For example, in the illustrated embodiment, the photographing optical system fixedly attached to the camera is explained, but
The present invention is not limited to this, and can be applied to the case of a photographic optical system that is exchangeably mounted.

Further, in the illustrated embodiment, the variable magnification type photographing optical system is explained, but the present invention is not limited to this, and may be applied to a single focus type photographing optical system having a specific focal length. Can be applied.

Furthermore, in the illustrated embodiment, an active type device is used as the AF means, but it is also possible to use AF means of another type or method.

[0066]

As described above, in the camera capable of expanding the short-distance photographing range of the present invention, in the camera having the automatic distance measuring means, the exposure calculating means or the flashmatic means, the object on the short-distance side at the time of photographing is photographed. a field depth, the aperture value at the time of photographing is determined by the exposure element value information, such as brightness and film sensitivity value, the focal distance and the open F _NO of the subject, or the f-number at the time of exposure determined by the flashmatic means It is calculated based on this, and based on this, the short-range shooting limit value of the automatic distance measuring means is set to a value according to the aperture value at the time of shooting, so practical short-distance shooting is possible The range can be significantly expanded compared to conventional ones.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a camera capable of expanding a short-distance shooting range according to the present invention.

FIG. 2 is an explanatory diagram for describing a photographing limit on a short distance side determined by a depth of field corresponding to an F _NO value at the time of photographing.

FIG. 3 is a flow chart diagram for explaining a series of operating states in the camera of FIG.

FIG. 4 is an explanatory diagram for explaining a photographing limit on a short distance side, which is determined by a depth of field when an open F _NO value is set.

[Explanation of symbols]

 1 CPU for control (CPU) 2 Variable magnification photographing optical system 3 Automatic distance measuring device (AF device) 3a Infrared light emitting unit 3b Distance measuring light receiving unit 4 Short-distance warning means (AF monitor display means) 5 Photometric device 5a Photometric device Light receiving section 6 Film sensitivity value detecting means 7 Shutter control section 8 Variable magnification position detecting means 9 Shutter release member

Claims (5)

[Claims] 1. An automatic distance measuring means for automatically measuring the distance to a subject, and a photometric means for measuring the brightness of the subject,
In a camera including at least an exposure calculation means for calculating a proper exposure value based on photometric value information from the photometry means, and an automatic exposure control means for realizing a proper aperture value based on the calculation value from the exposure calculation means Providing a short-distance warning determination means capable of issuing a short-distance warning based on the distance-measurement value information from the automatic distance-measuring means, and setting a photographing limit value of the short-distance warning determination means to at least a proper value from the exposure calculation means. A camera capable of expanding a short-distance shooting range, characterized in that the camera can be changed based on information on an aperture value. 2. An automatic distance measuring means for automatically measuring the distance to the subject, and a photometric means for measuring the brightness of the subject.
Exposure calculation means for calculating an appropriate exposure value based on at least photometric value information from the photometry means, shooting mode selection means for selecting a natural light shooting mode and a flash light shooting mode, and the exposure calculation in the natural light shooting mode A camera provided with automatic exposure control means for realizing an appropriate aperture value based on a calculated value from the means, and flashmatic means for forming an appropriate aperture value based on a guide number in a flash photography mode, Provided is a short-distance warning determination means capable of issuing a short-distance warning based on the distance-measurement value information from the distance-measuring means. A camera capable of expanding a short-distance shooting range, characterized in that the camera can be changed on the basis of information on an appropriate aperture value formed by. 3. An automatic distance measuring means for automatically measuring the distance to the subject, and a photometric means for measuring the brightness of the subject,
DX code reading means for reading the DX code of a film cartridge loaded in the camera, and an appropriate exposure value is calculated based on at least film sensitivity value information from the DX code reading means and photometric value information from the photometric means. In the camera, the camera is provided with an exposure calculation means for controlling the exposure, and an automatic exposure control means for realizing an appropriate aperture value based on the calculated value from the exposure calculation means. A short-distance warning determination means that can issue a warning is provided, and the photographing limit value of the short-distance warning determination means can be changed based on at least the film sensitivity value information from the DX code reading means. A characteristic camera that can expand the short-range shooting range. 4. A variable magnification photographing optical system capable of changing a focal length, automatic distance measuring means for automatically measuring a distance to a subject, photometric means for measuring brightness of the subject, and at least the photometric means. In the camera provided with the exposure calculation means for calculating the proper exposure value based on the photometry value information from the camera and the automatic exposure control means for realizing the proper aperture value based on the calculation value from the exposure calculation means, A short-distance warning determination means that can issue a short-distance warning based on distance-measurement value information from the distance means is provided, and the photographing limit value of the short-distance warning determination means is at least the focal length from the variable magnification photographing optical system. A camera capable of expanding a short-distance shooting range, characterized in that the camera can be changed based on the information of. 5. A fixed-mounting type photographing optical system or an interchangeable type photographing optical system whose opening F _NO changes, automatic distance measuring means for automatically measuring the distance to the subject, and photometric means for measuring the brightness of the subject. And an exposure calculation means for calculating a proper exposure value based on at least the photometric value information from the photometry means, and an automatic exposure control means for realizing a proper aperture value based on the calculation value from the exposure calculation means. The camera is provided with a short-distance warning determination means capable of issuing a short-distance warning based on the distance measurement value information from the automatic distance measurement means, and the photographing limit value of the short-distance warning determination means is at least from the photographing optical system. A camera capable of expanding a short-distance shooting range, characterized in that it can be changed based on the information of the open F _{NO at} that time.