JP2003337277A - Optical equipment - Google Patents

Abstract

(57) [Summary] [PROBLEM] To make it possible to take a picture that can withstand viewing while focusing on a subject and defocusing dust and dust in the air and near a photographic optical system, and further improve the performance of automatic focusing. Let it. SOLUTION: An optical system 1 including a focus lens group for focus adjustment which moves on an optical axis and forms an object image on a predetermined surface, a lens drive unit 11 for driving the focus lens group, and a Position detecting means for detecting the position, and control means 7 for driving and controlling the lens driving means
Storage means for preliminarily storing control information for driving and controlling the focus lens group; aperture means 3 for limiting the light amount of the optical system; and aperture detection means 5 for detecting the aperture diameter of the aperture means. Then, the control means varies the drive range of the focus lens group from the output of the aperture detection means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device equipped with an automatic focusing device in an image pickup device such as a video camera or an electronic still camera.

[0002]

2. Description of the Related Art Conventionally, in automatic focusing control in a silver salt camera, a method of measuring a subject distance has been mainly used, but in a camera using a photoelectric conversion image pickup device such as a video camera or an electronic still camera, A method that mainly uses an image signal obtained from the photoelectric conversion image pickup device is adopted.
As an automatic focusing method using this image signal, various methods such as a mountain climbing method have been proposed (JP-A-62-1).
No. 03616, etc.).

The first optical system on the object side is the first optical system.
Focusing by moving the lens group behind the group,
Various proposals have been made to adopt a so-called rear focus method. This is because the rear focus system moves a relatively small and lightweight lens group, so the driving force of the lens group is small and quick focusing is possible, so it has compatibility with the auto focus system. Because there is.

For example, JP-A-62-206516, JP-A-62-24213 and JP-A-63-247.
In Japanese Laid-Open Patent Application No. 316 and Japanese Patent Laid-Open No. 4-43311, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a third lens group having a positive refractive power are sequentially arranged from the object side. 4 of the 4th group
It has one lens group, and the second group is moved to perform zooming.
The image plane variation due to zooming is corrected by moving the fourth lens group and focusing is performed.

[0005]

[Problems to be Solved by the Invention] By the way, in recent years and in the future, as the image quality and the photographic optical system have become higher and higher in magnification, various functions are required to have higher performance in order to widen the range of photography. Has been done.

In particular, there is a strong demand for a wide angle of view in the photographing optical system, and accordingly, there is a demand for higher performance of various functions. However, in the function of the conventional image pickup apparatus, widening the angle of only the taking optical system causes a number of problems.

One of them has a problem that dust or dust floating between a subject and a photographing optical system is photographed during photographing. Further, under more severe conditions, a phenomenon may occur in which dust and dust existing in the vicinity of the photographing optical system are captured.

On the other hand, in the performance of autofocus, it takes a long time from blurring to focusing and there is a problem to eliminate the chance of occurrence of blurring.

The present invention has been made under such a background, and makes it possible to shoot an image that can be enjoyed by viewing while focusing on an object while defocusing dust and dust in the air or in the vicinity of the imaging optical system. Another object of the present invention is to provide an optical device having an automatic focusing control system that further improves the performance of automatic focusing.

[0010]

In order to achieve the above object, the present invention provides an optical system including a focus lens group for focus adjustment which moves on the optical axis to form an object image on a predetermined surface. Lens driving means for driving the lens group, position detecting means for detecting the position of the focus lens group, control means for driving and controlling the lens driving means, control information for driving and controlling the focus lens group are stored in advance. Storage means, diaphragm means for limiting the light amount of the optical system, diaphragm detection means for detecting the diaphragm diameter of the diaphragm means, and the control means determines the drive range of the focus lens group from the output of the diaphragm detection means. The present invention provides an optical device characterized by varying.

Here, the optical system is characterized in that it is a zoom lens having a movable lens group for zooming and zoom position detection means. Further, the control means is characterized in that the drive range of the focus lens group is changed from the output of the aperture detection means, or the output of the zoom position detection means and the output of the aperture detection means. Further, the control means has an automatic focusing means for automatically focusing, and the operating range of the means is changed according to the output of the aperture detection means,
The feature is that it can be changed. Further, the control means has an automatic focusing means for automatically focusing, and the operating range of the means is fluctuated and varied according to the output of the aperture detection means and the output of the zoom position detection means. It has a feature.

According to the present invention, an optical system for forming an object image on a predetermined surface, which includes a focus lens group for focus adjustment, which moves on the optical axis, lens driving means for driving the focus lens group, and the focus Position detecting means for detecting the position of the lens group, control means for driving and controlling the lens driving means, storage means for storing control information for driving and controlling the focus lens group in advance, and limiting the light amount of the optical system. A stop means and a stop detection means for detecting a stop diameter of the stop means are provided. In the control information of the storage means, focus shortest focus position information is stored in advance, and the output of the stop detection means is used to determine the focus lens group. The present invention provides an optical device characterized by varying the closest end position.

Here, the optical system is characterized in that it is a zoom lens having a moving lens group for zooming and zoom position detecting means. Further, the control means is characterized by changing the closest end position of the focus lens group from the output of the aperture detection means, or the output of the zoom position detection means and the output of the aperture detection means. further,
The control means has an automatic focusing means for automatically focusing, and is characterized in that the closest end position of the means is fluctuated and varied according to the output of the aperture detection means. Further, the control means has an automatic focusing means for automatically focusing, and varies and varies the closest end position of the means according to the output of the aperture detection means and the output of the zoom position detection means. It is characterized by that.

Further, according to the present invention, there is provided an optical system for forming an object image on a predetermined surface, which includes a focus lens group for focus adjustment which moves on the optical axis, a lens driving means for driving the focus lens group, and the focus. Position detecting means for detecting the position of the lens group, control means for driving and controlling the lens driving means, storage means for storing control information for driving and controlling the focus lens group in advance, and limiting the light amount of the optical system. A diaphragm means, a diaphragm detecting means for detecting a diaphragm diameter of the diaphragm means, focus infinity focus position information is stored in advance in the control information of the storage means, and the focus lens is output from the diaphragm detecting means. (EN) An optical device characterized by varying the infinite position of a group.

Here, the optical system is characterized in that it is a zoom lens having a moving lens group for zooming and zoom position detecting means. Further, the control means is characterized in that the infinite end position of the focus lens group is changed from the output of the aperture detection means, or the output of the zoom position detection means and the output of the aperture detection means. Further, the control means has an automatic focusing means for automatically focusing, and the infinite end position of the means is fluctuated and varied according to the output of the aperture detection means. Further, the control means has an automatic focusing means for automatically focusing, and varies and varies the infinite end position of the means according to the output of the aperture detection means and the output of the zoom position detection means. Is characterized by.

The present invention further includes an optical system for forming an object image on a predetermined surface, which includes a focus lens group for focus adjustment which moves on the optical axis, lens driving means for driving the focus lens group, and the focus lens. Position detecting means for detecting the position of the lens group, control means for driving and controlling the lens driving means, storage means for storing control information for driving and controlling the focus lens group in advance, and diaphragm for limiting the light amount of the optical system. Means, an aperture detection means for detecting the aperture diameter of the aperture means, and the control information of the storage means stores in advance focus shortest focus position and infinite end focus position information, and outputs the aperture detection means. Therefore, the present invention provides an optical device characterized by varying the close-up and infinity positions of the focus lens group.

Here, the optical system is characterized in that it is a zoom lens having a moving lens group for zooming and zoom position detecting means. Further, the control means is characterized by varying the close-up and infinite end positions of the focus lens group from the output of the aperture detection means or the output of the zoom position detection means and the output of the aperture detection means. further,
The control means has automatic focusing means for automatically focusing, and is characterized in that the closest end and infinite end positions of the means are varied and varied according to the output of the aperture detection means. Further, the control means has an automatic focusing means for automatically focusing, and the close end and infinite end positions of the means are changed according to the output of the aperture detection means and the output of the zoom position detection means. ,
It is characterized by being variable. Further, the control means is
Has automatic focusing means for automatically focusing, mode switching means for operating focus automatically or manually,
When the output of the mode switching means is the manual focus mode, it has a drive range in the manual focus mode, and when the output is the automatic focus mode, the operating range is the output of the aperture detection means and the zoom position detection means. It is characterized in that it fluctuates and is changed according to the output. Further, the control means has an automatic focusing means for automatically focusing and a mode switching means for operating the focus automatically or manually, and the output of the mode switching means is the same in both the manual focus mode and the automatic focus mode. It is characterized in that the operating range is changed and varied according to the output of the aperture detection means and the output of the zoom position detection means.

Further, in the invention, it is characterized in that the optical device has a replaceable optical system.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be specifically described with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the schematic arrangement of an image pickup apparatus according to the first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes an optical system, which is composed of a rear focus zoom lens (hereinafter referred to as an RFZ lens) having a four-group structure including four lens groups. That is, the RFZ lens 1 includes a first lens group (hereinafter referred to as a front lens) 101 which is a fixed lens group, a second lens group (hereinafter referred to as a variator) 102 which is a movable lens group and has a variable magnification function, A third lens group (hereinafter referred to as afocal) 103 which is a fixed lens group, a focusing function which is a moving lens group, and has a function as a compensator for correcting a change in the image plane position due to a zooming operation. It is composed of a fourth lens group (hereinafter referred to as a focus compensating lens).

Reference numeral 2 is a photoelectric conversion element such as a CCD, 3 is a diaphragm for adjusting the amount of light incident on the photoelectric conversion element 2, 4 is a diaphragm driving unit for changing the aperture of the diaphragm 3, and 5 is a diaphragm 3.
Is a detection circuit for detecting the opening degree (aperture amount) of the diaphragm 3 based on the output signal of the diaphragm position detection section 5, and 7 is an overall operation for the image pickup operation by the image pickup apparatus. It is a control unit that controls.

The control unit 7 is composed of a microcomputer, and has a CPU, ROM, RAM (not shown).
have. According to the control program stored in the ROM, the CPU controls various operations such as movement control of the variator 102 for the autofocus (AF) processing and the focus compensating lens 104 while using the RAM as a work area and the like.

Reference numerals 8 and 9 denote motors such as a stepping motor for moving the variator 102 and the focus compensating lens 104, respectively.
Are driven by motor drivers 10 and 11, respectively. Reference numeral 12 is an amplifier for amplifying the output signal of the photoelectric conversion element 2, and 13 is a process circuit for converting the amplified signal into a video signal such as an NTSC video signal.

Numeral 14 indicates AF by the output of the process circuit 13.
It is an AF control unit to be operated. As the AF method,
Although a mountain climbing type or the like has been proposed, the basic principle thereof is well known, for example, from Japanese Patent Laid-Open No. 62-103616, and therefore detailed description thereof is omitted here.

FIG. 2 shows the position of the focus lens (hereinafter referred to as Fnp) which covers the shortest focusing distance at the focal length and the shortest focusing distance according to the aperture value. In the present invention, the shortest focusing distance may or may not differ depending on the focal length as described above. This shortest focusing distance may be determined based on the optical performance of the lens, the characteristics of the product, and the controllability, and is not limited.

For example, Fnp at F1.8 is "Fnp-1.8" in the figure, and Fnp at F16 is "Fnp-F16" in the figure. It can be seen that the larger the value, the more the stop position is on the infinite side.

In consideration of this point, the present invention varies the stop position of the focus lens according to the aperture value, avoids focusing on an object closer than the shortest focusing distance than necessary, and focuses on the object. At the same time, dust and dust in the air or near the shooting optical system are made out of focus to enable shooting that can be appreciated.

Next, the flow of the control unit 7 is shown in FIG.

The control section 7 reads the zoom position from the pulse count at 301, the current F-No from the output of the aperture detection circuit 6 at 302, the focus lens position from the pulse count at 303, and the zoom position at 304. And Fnp of the focus lens is calculated from the aperture value and Fnp is calculated at 305.
The current focus position is compared with the current focus position. If the focus position is on the infinite side of Fnp, the flow exits at that focus position, and if the focus position is on the near side of Fnp, the focus is driven by that difference at 306. Let

Although it has been stated that Fnp is calculated from the zoom position and the aperture value, Fnp is previously stored in the control means.
It is also possible to have a table corresponding to the zoom position and the aperture value, and to draw out Fnp corresponding to them. Further, this information may be held in a rewritable storage means. As a result, the controllability can be adjusted to the product form, and the controllability can be arbitrarily changed according to the optical characteristics.

By thus limiting the focus driving range to the close-up side, it is possible to prevent the focus from being driven more than necessary, and to focus on the subject while not collecting dust or dust in the air or near the photographing optical system. As a result, there are more opportunities to take pictures that can be appreciated, and it is also effective in saving power.

(Second Embodiment) The configuration of the second embodiment is the same as that of the first embodiment, and the control contents of the control unit 7 are different from those of the first embodiment.

FIG. 4 shows the position of the focus lens (hereinafter referred to as Fip) that covers the shortest focusing distance at the focal length and the infinite distance by the aperture value.

For example, the Fip at F1.8 is "Fip-1.8" in the figure, and the Fip at F16 is "Fip-F16" in the figure, the larger the F value, the closer to the stop position. Recognize.

In consideration of this point, the present invention varies the drive range of the focus lens according to the depth, avoids the focus lens from being driven to the infinite side more than necessary, and provides the infinite side drive limitation of the focus. AF accuracy and focusing time can be shortened, and AF performance can be improved.

Next, the flow of the control section 7 is shown in FIG.

The control unit 7 reads the zoom position from the pulse count at 501, the current F-No from the output of the aperture detection circuit 6 at 502, and the infinity side stop position of the focus lens from the zoom position and aperture value at 503. Calculate and set the drive range, and read the focus lens position from the pulse count. 504
In step 505, Fip is calculated from the focal length, the focus position, and the aperture value, and in step 505, the Fip and the focus position are compared. If the focus position is on the close side, the flow exits at that focus position, and if it is on the infinite side, then 5
At 06, the focus is driven by the difference.

(Third Embodiment) The configuration of the third embodiment is the same as that of the first and second embodiments,
The control contents of the control unit 7 are different from those of the first and second embodiments.

According to the present invention, the drive range of the focus lens is changed so as to avoid focusing on a subject at a distance shorter than the shortest focusing distance more than necessary, while focusing on the subject while in the air or near the photographing optical system. In addition to making dust and dust out of focus and enabling shooting that can withstand viewing, limit the drive range of the focus lens according to the depth and focus on a subject farther than infinity distance than necessary. By avoiding the above, by limiting the drive of the focus lens, it is possible to eliminate unnecessary driving, shorten the AF accuracy and focusing time, and improve the AF performance.

Next, the flow of the control unit 7 is shown in FIG. The control unit 7 reads the zoom position from the pulse count at 601, reads the current F-No from the output of the aperture detection circuit 6 at 602, and calculates the close position and infinite side stop position of the focus lens from the zoom position and aperture value at 603. Then, set the drive range and read the focus lens position from the pulse count. At 604, the Fnp is calculated from the focal length, the focus position, and the aperture value.
And Fip are calculated, and Fnp and Fi are calculated at 605.
p and the focus position are compared, and the focus position is Fnp
If the focus position is out of the range between Fnp and Fip, the focus is driven by the difference between them when the focus position is out of the range between Fnp and Fip.

(Fourth Embodiment) Although the object of the present embodiment is the same as that of the first embodiment, the embodiment is different in that it is a replaceable lens. The following is a description with reference to FIG. 7.

The image pickup apparatus according to the fourth embodiment is an interchangeable lens type image pickup apparatus, and the camera unit control section 16 of the camera unit 40 controls the diaphragm operation in the video signal generated by the process circuit 13. A signal for performing the above is transmitted to the lens unit controller 7 of the lens unit 30 via the camera contact 17 and the lens contact 18. The lens unit controller 7 performs AF control and aperture control based on the signal transmitted from the camera unit controller 16,
The zoom position, the focus position, the aperture position, etc. are transmitted to the camera unit controller 16.

Next, the flow of the control section 7 is shown in FIG.

The control unit 7 reads the zoom position from the pulse count at 801, reads the current F-No from the output of the aperture detection circuit 6 at 802, and stops the focus lens from the zoom position and aperture value at 803 and closes to infinity. Calculate the position, set the driving range,
Read the focus lens position from the pulse count. In step 804, Fnp and Fip are calculated from the focal length and focus position, and the aperture value, and in step 805, Fnp and Fip are compared with the focus position. If the focus position is within the range of Fnp and Fip, the flow exits the focus position as it is. , Fnp and Fip are out of the range, in 806, the focus is driven by the difference.

Although it has been described that Fnp and Fip are calculated from the zoom position and the aperture value, they are stored in advance in the control means as a table corresponding to the zoom position and the aperture value, and Fnp, Fnp and The Fip may be pulled out. Further, this information may be held in a rewritable storage means. As a result, the controllability can be adjusted to the product form, and the controllability can be arbitrarily changed according to the optical characteristics.

In the case of an interchangeable lens, each lens has different data, and control may be performed according to the characteristics of each lens.

For example, a wide-angle lens is particularly effective in the present invention because the above-mentioned problem is likely to occur as described above. In addition, it is an interchangeable lens that covers from wide-angle to telephoto like a zoom lens, or in the case of telephoto, the above-mentioned problems do not occur depending on the focus position or focal length position of the subject from the depth of field. In some cases, the presence or absence of the setting of the drive range depending on the depth and the focus position range for moving may be determined in advance depending on the focus position of each lens.

The utilization of the present embodiment is not particularly limited depending on the depth of field such as the focus position and the focusing range of the lens. Further, it is also possible to change only the closest end by depth, or to perform only infinity, and it is not limited to change both ends depending on depth, and it is optional depending on the optical device such as individual lens characteristics and product characteristics. You can use them properly.

(Fifth Embodiment) FIG. 9 shows the configuration of the fifth embodiment.

The present embodiment is to change the presence / absence of the limitation of the focus drive range according to the mode switching.

That is, the drive range is limited according to the depth during AF, but in the manual focus (hereinafter referred to as MF) mode, drive limitation is not performed. In the MF mode, if the drive range is limited according to the depth, there is a possibility that the change in the scene or the shooting intention only with the MF may be limited. Therefore, in the MF mode, the focus drive range is limited by the specifications. A focus drive range that is different from AF and does not depend on the depth is set so that the focus range can be driven.

In FIG. 9, the same parts as those of the first, second and third embodiments will not be described. Reference numeral 15 is a mode switch capable of switching between AF and MF modes.

Next, the flow of the control unit 7 is shown in FIG.

The control section 7 determines the focus mode at A00, sets the drive range for MF at A07 if MF is set, and exits the flow. If AF is set, the zoom position is read from the pulse count at A01, and A0 is set.
In 2, the current F-No is read from the output of the aperture detection circuit 6, in A03, the focus lens close-side stop position is calculated from the zoom position and aperture value, the drive range is set, and the focus lens position is determined from the pulse count. Read. In A04, Fnp is calculated from the focal length, the focus position, and the aperture value, and in A05, the Fnp and the focus position are compared. If the focus position is on the infinite side, the flow is left at the focus position as it is,
When the subject is on the close side, the focus is driven by the difference in A06.

(Sixth Embodiment) The configuration of this embodiment is the same as that of the fifth embodiment, but the purpose is different.

In this embodiment, the limitation of the focus drive range is made variable in both AF and MF according to the depth.

That is, even in the MF mode, the drive range is limited according to the depth, and the focus is not driven closer to the infinity side or the infinity side than necessary for focusing.
The focus operation can be performed smoothly even when the mode is switched to, and the focus will not be driven more than necessary for power saving, and the amount of MF operation from the near end to the infinite end will be reduced. It also has the effect of reducing the load. Also, even in MF, the focus position near the in-focus point is automatically limited without relatively performing the focus operation.
It also brings the effect of improving shooting at F.

Next, the flow of the control unit 7 is shown in FIG.

The control unit 7 reads the zoom position from the pulse count at B01, the current F-No from the output of the aperture detection circuit 6 at B02, and at B03 the stop position on the close side of the focus lens from the zoom position and aperture value. Is calculated, the drive range is set, and the position of the focus lens is read from the pulse count. B0
In F4, Fnp is calculated from the focal length, focus position, and aperture value, and in B05, Fnp is compared with the focus position. If the focus position is on the infinity side, the flow exits at that focus position, and if it is on the close side, At B06, the focus is driven by the difference.

[0061]

As described above, according to the present invention,
While focusing on the subject, dust and dust in the air or near the shooting optical system are out of focus, and shooting that can withstand viewing is possible.
In addition, by limiting the drive range of the focus lens according to the depth, avoiding focusing on a subject farther than infinity more than necessary, and setting a focus drive limit to drive more than necessary. It eliminates AF accuracy and focusing time to improve AF performance.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the first embodiment of the present invention.

FIG. 3 is a flowchart for explaining the first embodiment of the present invention.

FIG. 4 is a diagram for explaining a second embodiment of the present invention.

FIG. 5 is a flow chart for explaining a second embodiment of the present invention.

FIG. 6 is a flow chart for explaining a third embodiment of the present invention.

FIG. 7 is a diagram for explaining the third embodiment of the present invention.

FIG. 8 is a flow chart for explaining a fourth embodiment of the present invention.

FIG. 9 is a diagram for explaining the fifth embodiment of the present invention.

FIG. 10 is a flowchart for explaining a fifth embodiment of the present invention.

FIG. 11 is a flowchart for explaining a fifth embodiment of the present invention.

[Explanation of symbols]

1 Optical system 3 aperture 5 Aperture position detector 6 Detection circuit 7 Control unit (CPU, ROM, RAM) 8, 9 motor 14 AF control unit 102 Second lens group (variator lens) 104 4th lens group (focus compensating lens)

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Claims (5)

[Claims] 1. An optical system that includes a focus lens group for moving a focus on an optical axis to form an object image on a predetermined surface, a lens driving unit that drives the focus lens group, and the focus lens group. Position detecting means for detecting the position, a control means for driving and controlling the lens driving means, a storage means for storing control information for driving and controlling the focus lens group in advance, and a light amount of the optical system. An optical system characterized by comprising: diaphragm means for limiting and diaphragm detecting means for detecting a diaphragm diameter of the diaphragm means, wherein the control means varies the drive range of the focus lens group from the output of the diaphragm detecting means. machine. 2. The optical apparatus according to claim 1, wherein the optical system is a zoom lens having a movable lens group for zooming and zoom position detection means. 3. The drive range of the focus lens group according to claim 1, wherein the control means outputs from the aperture detection means, or the output from the zoom position detection means and the output from the aperture detection means. An optical device characterized in that it fluctuates. 4. The invention according to claim 1, wherein the control means has an automatic focusing means for automatically focusing, and the operating range of the automatic focusing means is determined according to the output of the aperture detection means. An optical device that is characterized by varying and changing. 5. The invention according to claim 1, wherein the control means has an automatic focusing means for automatically focusing, and the operating range of the automatic focusing means is the output of the aperture detection means and the output of the aperture detection means. An optical device characterized in that it is varied and variable according to the output of the zoom position detecting means.