JP4015269B2 - Electronic camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic camera, and more particularly, to an electronic camera configured so that at least a macro conversion lens can be attached to a photographing lens system, and a focus lens constituting a part of the photographing lens system when the macro conversion lens is attached It relates to group movement control.
[0002]
[Prior art]
Conventionally, a subject image formed by a photographing lens system is photoelectrically converted into an electrical signal using an imaging device, and the image signal is recorded on a recording medium or the like as still image data or moving image data. In so-called electronic still cameras, video cameras, and the like (hereinafter referred to as electronic cameras, etc.), the focal length defined by the photographic lens system fixed to the apparatus is fixed by attaching it to the outside of the photographic lens system, for example, the tip. A so-called conversion lens that can realize an optical expansion function of the photographing lens system, such as conversion to a different focal length, is generally put into practical use.
[0003]
This conversion lens includes, for example, a wide-angle wide-conversion lens that can widen the shooting angle of view and ensure a wider shooting range, and a telephoto tele-conversion that can secure a larger shooting magnification and enlarge the desired subject image. There is a so-called macro conversion lens, which is a close-up system that shortens the distance to the closest object (hereinafter referred to as the shortest shooting distance) that can be photographed by a lens or a photographing lens system fixed to the apparatus.
[0004]
Among such conversion lenses, when a macro conversion lens is mounted on a photographing optical system such as an electronic camera, the range that can be imaged by a photographing lens system including the macro conversion lens, that is, from the shortest photographing distance is normal. The region up to the farthest shooting distance has an optical characteristic that it tends to be narrow.
[0005]
More specifically, for example, in a photographing lens system provided in an electronic camera or the like, a desired subject can be focused and photographed in a region from the shortest photographing distance = 30 cm to the farthest photographing distance = infinity. When a macro conversion lens is attached to a photographic lens system that is set to be capable of shooting, the entire photographic lens system including the macro conversion lens can focus on a desired subject and shoot, for example, the shortest photographic area. Usually, the distance = about 20 cm to the farthest shooting distance = about 35 cm.
[0006]
As described above, when the macro conversion lens is attached, the shortest shooting distance in the macro region is shortened, and close-up shooting at a higher magnification becomes possible.
[0007]
On the other hand, a conventional electronic camera or the like is generally put into practical use with an automatic focus adjustment means (hereinafter referred to as an AF means). As this AF means, a so-called contrast detection method is used. Generally used widely.
[0008]
A general contrast detection AF means moves high-frequency components included in an image signal acquired by an image sensor at a plurality of predetermined lens positions while moving a focus lens group constituting a part of a photographing lens system. Extraction is performed, and the in-focus position is detected by comparing the amount of the high-frequency component.
[0009]
According to this method, since the in-focus position is detected using the image sensor, a constituent member such as a distance measuring sensor for performing the in-focus position detecting operation or the distance measuring operation is unnecessary. In addition, there is an advantage that the focus detection accuracy can be easily made extremely high. However, on the other hand, there is a problem that the time required for the focus detection operation tends to be longer than that of the focus detection means (ranging means) using, for example, a general triangulation method. Yes.
[0010]
That is, the following series of operations are usually executed as a photographing operation accompanied by a focus detection operation (AF operation) in an electronic camera or the like that employs contrast detection AF means.
[0011]
First, a release signal for starting a photographing operation is generated by an operation of an operation unit such as a release SW of the photographer. As a result, the photographing operation is started. Upon receiving this release signal, the focus detection operation is first started. This focus detection operation is performed while the focus lens group is being driven, and therefore requires some time. Based on the result of the focus detection operation, the focus lens group is driven and moved to a predetermined focus position, and then an actual release process (photographing process) is performed.
[0012]
Therefore, in this case, it is clear that a predetermined time is required from the time when the photographer operates the release SW (when the release signal is generated) to the time when shooting is completed (when the release process is completed). There is a problem that the time lag at the time of shutter release becomes large.
[0013]
Therefore, in order to solve such a problem, the following means are used. That is, there are a plurality of modes such as a normal shooting mode for focusing on a subject at a normal shooting distance and a macro shooting mode for focusing on a subject at the closest shooting distance (macro area). A photographing mode is provided, and the photographer is configured to select a photographing mode according to the distance to a desired subject when photographing. The moving range of the focus lens group is set to be a predetermined range for each photographing mode. Therefore, when the release signal is generated, the focus lens group moves only within a predetermined range corresponding to the selected photographing mode and performs the focus detection operation.
[0014]
With this configuration, the amount of movement of the focus lens group performed in accordance with the focus detection operation can be reduced, so that the time required for the focus detection operation can be shortened, thereby reducing the time lag that occurs during the shutter release. It can be done.
[0015]
As an electronic camera using such means, various proposals have been made, for example, according to Japanese Patent Laid-Open No. 2-12213, and are generally put into practical use.
The electronic camera disclosed in JP-A-2-12213 has a macro shooting mode and a normal shooting mode. In each shooting mode, the focus lens group is moved in different predetermined moving ranges. The focus detection operation is performed.
[0016]
The farthest position of the focus detection range (movement range of the focus lens group) in the macro shooting mode and the closest position of the focus detection range (same as above) in the normal shooting mode are set to overlap each other. Thus, even when an error or the like occurs in the selection of the shooting mode by the operator, control is performed so that the focus detection operation can be executed without any problem.
[0017]
[Problems to be solved by the invention]
However, in a conventional electronic camera or the like in which the moving range of the focus lens group is set within a predetermined range depending on the shooting mode selected by the photographer, for example, when a macro conversion lens is attached to the shooting lens system, the following May cause problems as shown in.
[0018]
FIG. 3 is a conceptual diagram showing the relationship between the moving range of the focus lens group and the shooting distance (distance to a desired subject) during a focus detection operation in a conventional electronic camera or the like.
[0019]
In a normal case, the physical movement amount of the focus lens group 9a in the photographing lens system used for an electronic camera or the like is closer to the region on the close distance side than when focusing on the subject on the far side region. It has an optical characteristic that it tends to be larger when focusing on a certain subject.
[0020]
Considering this, when a plurality of shooting modes are set in a conventional electronic camera or the like, for example, the movement range in the normal shooting mode is subject distance = infinity to 60 cm, and the movement range in the macro shooting mode is subject distance = Usually, it is set to 60 cm to 30 cm or the like (see the state when the conversion lens is not attached in FIG. 3). With such a setting, the physical movement amount of the focus lens group 9a is set to be substantially the same in both shooting modes. However, in this case, the shooting range in the macro shooting mode is a very narrow range.
[0021]
When a macro conversion lens is attached to such a photographing lens system, an area that can be photographed by the photographing lens system including the macro conversion lens is such that the farthest object distance = 35 cm to the shortest photographing distance = 16 cm. If set, the moving range of the focus lens group 9a is as follows according to the selected photographing mode.
[0022]
That is, the movement range of the focus lens group 9a when the normal shooting mode is selected corresponds to the area of the subject distance = 35 cm to 22 cm, and the movement range of the focus lens group 9a when the macro shooting mode is selected is Corresponds to the area of subject distance = 22 cm to 16 cm (see the state when the conversion lens is mounted in FIG. 3).
[0023]
Therefore, even when photographing in an extremely narrow photographing region (35 cm to 16 cm) in the macro region, it becomes necessary to perform a mode switching operation, and the operability thereof is significantly lowered.
[0024]
In addition, since the photographing region that can be photographed is small, it is difficult to clarify the switching point of the photographing mode according to the subject distance, and there is a problem that an error is likely to occur in the detection result of the focus detection operation. Such a problem is not easy to solve even when the means disclosed in the above-mentioned JP-A-2-12213 is used.
[0025]
The present invention has been made in view of the above-described points, and an object of the present invention is to easily perform a photographing operation in a macro area without impairing operability even when a macro conversion lens is used. It is in providing an electronic camera capable of performing the above.
[0026]
[Means for Solving the Problems]
To achieve the above object, an electronic camera according to a first aspect of the present invention comprises a photographic lens system on which a macro conversion lens can be attached, and a part of the photographic lens system, and an object image is placed on an imaging surface of an image sensor. A focus lens group that forms an image, and a selection unit that selects at least two shooting modes of a normal shooting mode and a macro shooting mode; A focus detection means for detecting a focus position based on a contrast detection method; Movement control means for moving the focus lens group to a focus position detected by a focus detection means for detecting a focus position, the movement control means at least when the macro conversion lens is not attached. Controlling to move the focus lens group within a predetermined movement range set according to the photographing mode selected by the selection means out of the entire movement range in which the lens group can move, and when mounting the macro conversion lens, The focus lens group is controlled to move within the entire movement range of the focus lens group regardless of the photographing mode selected by the selection means.
[0027]
According to a second aspect of the present invention, in the camera according to the first aspect of the present invention, the camera according to the first aspect further includes detection means for automatically detecting a mounting state of the macro conversion lens, and the macro conversion lens is mounted on the photographing lens system. When detected by the detection means, the movement control means sets the movement range of the focus lens group to be the entire movement range of the focus lens group.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the illustrated embodiments.
FIG. 1 is a block diagram showing the internal configuration of an electronic camera according to an embodiment of the present invention.
[0029]
As shown in FIG. 1, the electronic camera 1 condenses a subject luminous flux and forms a subject image, and the subject image formed by the photographing lens system 9 is converted into an electrical signal. An imager 8 constituted by an image pickup device such as a CCD for photoelectric conversion, an image pickup circuit 10 for performing predetermined image processing (preprocessing) in advance on an image signal converted by the imager 8, and the image pickup circuit 10 An A / D conversion circuit 11 that converts an image signal (analog signal) output from the digital signal into a digital signal, a memory 12 such as a buffer memory composed of a DRAM or the like that temporarily stores the digitalized image signal, For example, a digital image signal stored in the memory 12 is converted into an analog signal having an optimum form for display on the LCD monitor 14, an image and the like. The LCD monitor 14 as an image display device to be displayed and the digital image signal stored in the memory 12 are subjected to data processing / compression processing and the like so that the digital image signal can be recorded in the memory card 16 as a recording medium. A memory card 16 and a compression / decompression circuit 15 for an image signal for performing a decompression process so as to obtain a signal in a form in which various image processes can be performed on a plurality of image data recorded in a compressed state are mounted. A memory card slot 17 composed of a mounting section and a card I / F (electric circuit), a system controller 21 which is a control means for controlling the entire electronic camera 1, and a part of the photographing lens system 9. An AF motor that performs a focusing operation by moving a focus lens group 9a that forms a subject image on the imaging surface of the imager 8 in the optical axis direction. 0, an AF motor control circuit 19 that controls the driving of the AF motor 20, a focusing circuit 18 that is a focus detection unit that performs focus detection of a subject image formed on the imaging surface of the imager 8, and a system controller 21 includes a plurality of input switch groups 22 for inputting various input signals to 21.
[0030]
For each switch constituting the input switch group 22, for example, a command signal for switching a shooting mode such as a normal shooting mode or a macro shooting mode is generated, a shooting mode switching SW 23 for selecting a desired shooting mode, and focus detection There are a release SW 24 for generating a command signal for starting a series of photographing operations such as an operation (AF operation) and a shutter release operation.
[0031]
The system controller 21 controls the AF motor control circuit 19 based on the focal position information detected by the focusing circuit 18 serving as a focus detection means, and the AF motor control circuit 19 controls the driving of the AF motor 20. Thus, the focus lens group 9a is moved. That is, each of these constituent members constitutes a movement control unit that moves the focus lens group 9a to a predetermined position.
[0032]
The photographing lens system 9 of the electronic camera 1 detects whether or not at least a macro conversion lens (hereinafter referred to as an MC lens) 2 among various conversion lenses is mounted, that is, whether the MC lens 2 is mounted. Two fixed contacts 9c constituting a part of the detecting means are provided, and these two fixed contacts 9c are electrically connected to the system controller 21.
[0033]
Further, the photographing lens system 9 has a mounting portion (not shown) for the MC lens 2 formed at the tip thereof, so that the MC lens 2 can be mounted from the outside, for example, the front side. ing. The mounting portion is formed by, for example, a mounting means or the like, and a dedicated connecting member corresponding to the MC lens 2 is provided.
[0034]
On the other hand, the MC lens 2 is provided with a mounting portion (not shown) that can be connected to the mounting portion of the photographing lens system 9 at the rear end thereof. Two contacts 2c corresponding to the two fixed contacts 9c are provided. When the MC lens 2 is attached to the photographing lens system 9, both the contacts 2c and 9c are arranged at positions where they are in contact with each other.
[0035]
A resistor 2b as a sensor member having a specific resistance value is connected between the two contact points 2c. The resistor 2b has a specific resistance value depending on the type of the conversion lens. That is, the system controller 21 on the electronic camera 1 side detects the resistance value of the resistor 2b to detect the type of the conversion lens attached to the photographing lens system 9, and at least the electronic camera 1 is attached. Whether or not the conversion lens is the MC lens 2 can be detected.
[0036]
The operation of the electronic camera 1 configured as described above will be described below.
A series of processing when the focus detection operation (AF operation) is performed in the electronic camera 1 is as follows.
[0037]
The electronic camera 1 uses contrast detection AF means. When a power switch (not shown) of the electronic camera 1 is turned on, power is supplied to each component in the camera 1 to enter a state where a photographing operation can be started, that is, a photographing mode. When the release SW 24 or the like is operated in this state, a command signal for performing a photographing operation is generated. In response to this, the system controller 21 first starts control for performing the AF operation.
[0038]
The system controller 21 controls the AF motor 20 via the AF motor control circuit 19, and arranges the focus lens group 9a at a predetermined reference position. Then, data on the focus detection operation in this state, that is, the in-focus state is acquired.
[0039]
The operation performed here will be described in more detail.
A light beam representing a subject image transmitted through the photographing lens system 9 and irradiated onto the imaging surface of the imager 8 is subjected to predetermined photoelectric conversion by the imager 8 to generate an image signal. This image signal is sent to the memory 12 and the focusing circuit 18 through the imaging circuit 10 and the A / D conversion circuit 11.
[0040]
Next, the focusing circuit 18 extracts, for example, a predetermined portion of luminance data in the vicinity of the substantially central portion of the image from the image signal converted into the digital signal, and a high-pass filter or the like (not shown) from the luminance data. To extract high-frequency components. Data regarding this high frequency component is output to the system controller 21 as an AF evaluation value. The system controller 21 temporarily stores the AF evaluation value data in an internal register unit or the like.
[0041]
Subsequently, the focus lens group 9a is moved by a predetermined amount in the optical axis direction, and the same processing is repeated. A plurality of AF evaluation values collected in this way are compared, and data having the peak value (maximum value) is detected. This is the data of the in-focus position.
[0042]
Based on this, the system controller 21 controls the AF motor 20 via the AF motor control circuit 19 to move the focus lens group 9a to a predetermined focus position. Thereby, the focus detection operation and the focusing operation are completed.
[0043]
Note that a so-called stepping motor or the like is used for the AF motor 20, and step driving is performed under the control of the AF motor control circuit 19. Therefore, the position of the focus lens group 9a is obtained by the system controller 21 counting the number of step drive pulses of the AF motor 20 and performing a calculation based on the counted number.
[0044]
Further, the detailed configuration of the photographic lens system 9 is not shown, but the outline thereof is as shown below.
The focus lens group 9a is a so-called inner focus type provided at the rearmost end of the photographic lens system 9, and together with other photographic lens groups etc., in the lens cylinder holding the photographic lens optical system 9, It is arranged so that it can move in the optical axis direction.
[0045]
The initial position of the focus lens group 9a is detected by using a detection means such as a photosensor disposed in the photographing lens system 9. The initial position of the lens group 9a is also used as detection data for the absolute position of the focus lens group 9a as a countermeasure when the power switch is turned on or when an abnormality occurs. ing.
[0046]
Next, the operation when the MC lens 2 is mounted on the front side of the photographing lens system 9 of the electronic camera 1 will be described below.
FIG. 2 is a flowchart showing the operation of the electronic camera 1 in the shooting mode.
[0047]
As described above, the electronic camera 1 enters a photographing mode when a power switch (not shown) is operated to be turned on. In this state, the system controller 21 monitors whether or not the MC lens 2 is attached to the photographing lens system 9 (step S1 in FIG. 2).
[0048]
If it is determined in step S1 that the MC lens 2 is attached to the photographic lens system 9, the process proceeds to step S2. In step S2, the system controller 21 is selected by the photographic mode switching SW23. Regardless of the shooting mode, the movement range of the focus lens group 9a during the focus detection operation is set to move within the entire movement range in which the lens group 9a can move, and the operation of the subsequent shooting mode is continued ( return).
[0049]
On the other hand, if it is determined in step S1 that the MC lens 2 is not attached to the photographing lens system 9, the process proceeds to step S3. In step S3, the state of the photographing mode switching SW23 is confirmed. Here, if it is determined that the macro shooting mode is set by the shooting mode switch SW23, the process proceeds to the next step S4. In this step S4, the movement range of the focus lens group 9a during the focus detection operation is determined. A predetermined movement range corresponding to the macro shooting mode is set, and the subsequent shooting mode operation is continued (return).
[0050]
In step S3 described above, when it is determined that the shooting mode selected by the shooting mode switching SW23 is not the macro shooting mode, it is determined that the normal shooting mode is set. Accordingly, the process proceeds to step S5. In step S5, the moving range of the focus lens group 9a during the focus detection operation is set to move within a predetermined moving range corresponding to the normal shooting mode. Will continue (return).
[0051]
As described above, according to the above-described embodiment, when shooting is performed without attaching the macro conversion lens 2, the photographer can select the normal shooting mode and the macro shooting mode according to the distance to the desired subject. Any one of the shooting modes is selected by the shooting mode switching SW23. As a result, the electronic camera 1 is controlled so as to move the focus lens group 9a only within a predetermined movement range corresponding to the selected photographing mode when executing the focus detection operation. Can be shortened.
[0052]
When the macro conversion lens 2 is attached to the photographing lens system 9 of the electronic camera 1, the movement range of the focus lens group 9a during the focus detection operation is the same regardless of the selected photographing mode. Control is performed so that the entire movable range can be moved.
[0053]
With such a configuration, when close-up photography (macro photography) is performed with the macro conversion lens 2 attached, photography can be executed without worrying about the photography mode, and thus excellent operability. Can be obtained.
[0054]
In addition, the mounting state of the macro conversion lens 2 is configured to be automatically detected by the detection means, and when the detection means detects that the macro conversion lens 2 is mounted, the macro conversion lens 2 is automatically detected. Since the movement range of the focus lens group 9a during the focus detection operation (AF operation) and the focusing operation is controlled to be the entire movement range, it is possible to prevent an operation error of the photographer and the like. This can contribute to further improvement in operability.
[0055]
As described above, the electronic camera 1 of the present embodiment is provided with detection means for automatically detecting the mounting state of the MC lens 2, and when this detection means detects the mounting of the MC lens 2, The controller 21 controls the movement control means (the AF motor control circuit 19 and the like) so as to set the movement range of the focus lens group 9a to the entire movement range in which the lens group 9a can move.
[0056]
However, even if it is configured to perform such control, the electronic camera 1 is used when a conversion lens that is not provided with components such as contacts and resistors corresponding to the detection means is mounted. In this case, the wearing state cannot be automatically detected.
[0057]
Therefore, a modified example of the electronic camera considering such a case can be considered.
In other words, as an electronic camera of this modification, when a conversion lens (hereinafter referred to as an incompatible conversion lens) that does not correspond to a detection means for detecting the mounting state of the conversion lens provided on the photographing lens system 9 side is mounted. Further, a macro switch that is an operation member that can change the movement control of the focus lens group 9a by an arbitrary operation by the operator may be provided.
[0058]
In the electronic camera configured as described above, when a non-conversion conversion lens is attached to the photographing lens system 9, the photographer first operates the macro SW to turn it on. Then, in response to the input signal from the macro SW, the system controller 21 controls the AF motor control circuit 19 / AF motor 20 to set the movement range of the focus lens group 9a during the AF operation and the focusing operation. Control to move within the entire movement range.
As a result, even when a non-compatible MC lens is attached to the photographic lens system 9, it is possible to shoot the macro area without any trouble.
[0059]
In the present electronic camera 1, a memory card 16 that is detachably disposed is applied as a recording medium for recording an image signal. A fixed memory or the like may be used.
[0060]
Also, as a mounting part for the conversion lens such as the MC lens 2, an accessory such as a general screw-in type filter is usually provided at the tip of the photographing lens system 9 without providing a special mounting part for the conversion lens. You may make it utilize the thread groove etc. for mounting | wearing with a kind. In this case, the mounted portion on the MC lens 2 side can be made common with the mounted portion formed of a screw portion or the like in general accessories, which is efficient.
[0061]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an electronic camera that can easily perform a photographing operation in a macro region without impairing operability even when a macro conversion lens is attached and used.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram showing an internal configuration of an electronic camera according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation in a photographing mode in the electronic camera of FIG.
FIG. 3 is a conceptual diagram illustrating a relationship between a moving range of a focus lens group and a shooting distance (subject distance) during a focus detection operation in a conventional electronic camera or the like.
[Explanation of symbols]
1 …… Electronic camera
2. Macro conversion lens (MC lens)
2b: Resistance
2c …… Contact
8 …… Imager (image sensor)
9 …… Shooting lens system
9a: Focus lens group
9c: Fixed contact (detection means)
18 …… Focus circuit (focus detection means)
19 …… AF motor control circuit (movement control means)
20 …… AF motor
21 …… System controller (control means)
23 …… Shooting mode switching SW (selection means)

Claims (2)

A taking lens system that can be equipped with a macro conversion lens;
A focus lens group that forms a part of the photographing lens system and forms a subject image on the imaging surface of the imaging element;
A selection means for selecting at least two shooting modes of a normal shooting mode and a macro shooting mode;
A focus detection means for detecting a focus position based on a contrast detection method;
In the focal position detected by the focus detection means for detecting the focal position, and movement control means for moving the focusing lens group,
With
The movement control means is configured so that, at least when the macro conversion lens is not attached, the movement control means is within the predetermined movement range set according to the photographing mode selected by the selection means out of the whole movement range in which the focus lens group can move. Control to move the focus lens group, and control to move the focus lens group within the entire movement range of the focus lens group regardless of the shooting mode selected by the selection means when the macro conversion lens is mounted. An electronic camera characterized by It further comprises a detection means for automatically detecting the wearing state of the macro conversion lens,
When it is detected by the detection means that the macro conversion lens is attached to the photographing lens system, the movement control means sets the movement range of the focus lens group as the total movement range of the focus lens group. The electronic camera according to claim 1, wherein the electronic camera is set to be

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