U.S. patent application number 14/957467 was filed with the patent office on 2016-03-24 for lens apparatus and imaging apparatus detachable therefrom.
The applicant listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Yuji Tsuda.
Application Number | 20160088208 14/957467 |
Document ID | / |
Family ID | 50147681 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160088208 |
Kind Code |
A1 |
Tsuda; Yuji |
March 24, 2016 |
LENS APPARATUS AND IMAGING APPARATUS DETACHABLE THEREFROM
Abstract
An imaging apparatus includes a sensor configured to
photoelectrically convert light from an object to output a signal,
a selection unit configured to select one of a first exposure
control mode and a second exposure control mode having an exposure
changing amount per unit time larger than that of the first
exposure control mode, and a controller configured to perform
control to transmit diaphragm control information generated based
on the output signal from the sensor, first information, and second
information to a connected lens unit, wherein the first information
is about the exposure control mode selected by the selection unit,
and the second information is speed information of a diaphragm unit
corresponding to the lens unit.
Inventors: |
Tsuda; Yuji; (Yokohama-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
|
JP |
|
|
Family ID: |
50147681 |
Appl. No.: |
14/957467 |
Filed: |
December 2, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13973899 |
Aug 22, 2013 |
|
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14957467 |
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Current U.S.
Class: |
348/363 |
Current CPC
Class: |
H04N 5/238 20130101;
H04N 5/2355 20130101; H04N 5/2353 20130101; H04N 5/23245 20130101;
H04N 5/23203 20130101; H04N 5/23209 20130101 |
International
Class: |
H04N 5/235 20060101
H04N005/235; H04N 5/232 20060101 H04N005/232 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 27, 2012 |
JP |
2012-187064 |
Claims
1. A lens unit including a lens, the lens unit comprising: a
diaphragm unit configured to control exposure to adjust an incident
light amount; a memory configured to store speed information for
driving the diaphragm unit; and a controller configured to output
the speed information stored in the memory to an external
apparatus, wherein the controller controls the diaphragm unit based
on diaphragm control information periodically transmitted from the
external apparatus.
2. The lens unit according to claim 1, wherein the diaphragm
control information is associated with an exposure control mode of
the external apparatus.
3. The lens unit according to claim 1, wherein the diaphragm
control information is transmitted from the external apparatus
connected via a communication unit.
4. The lens unit according to claim 1, wherein the speed
information of the diaphragm unit includes information about a
variable range of controllable responsiveness of the diaphragm
unit.
5. The lens unit according to claim 1, wherein the speed
information of the diaphragm unit is generated in association with
stored information about a variable range of controllable
responsiveness of the diaphragm unit.
6. The lens unit according to claim 1, wherein the speed
information of the diaphragm unit indicates a minimum speed at
which the diaphragm unit is able to be driven.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. patent
application Ser. No. 13/973,899, filed Aug. 22, 2013, entitled
"LENS APPARATUS AND IMAGING APPARATUS DETACHABLE THEREFROM", the
content of which is expressly incorporated by reference herein in
its entirety. Further, the present application claims priority from
Japanese Patent Application No. 2012-187064 filed Aug. 27, 2012,
which is also hereby incorporated by reference herein in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a lens apparatus (lens
unit) detachable from an imaging apparatus main body, the imaging
apparatus main body (camera unit) from which the lens unit is
detachable, and an imaging apparatus that includes the lens
apparatus and the imaging apparatus main body.
[0004] 2. Description of the Related Art
[0005] Recently, there has been produced a video camera that
enables replacement of a lens unit. A feature of the product of
this category is that a user can interchangeably use lens units of
various features according to an object image to be captured. In
such an interchangeable lens system, there has been discussed a
system for controlling exposure. Specifically, an exposure state is
detected on a camera unit side, and information for controlling a
diaphragm of a lens unit side is generated on the camera unit side
so that the exposure state can coincide with a predetermined value,
and is transmitted to the lens unit side. The lens unit side
controls the diaphragm based on the information for controlling the
diaphragm, which has been received from the camera unit side (as
discussed in Japanese Patent Application Laid-Open No.
3-10580).
[0006] However, in the conventional imaging apparatus, no
consideration is given to the possibility that the responsiveness
(light amount change per unit time) of the diaphragm, mounted in
the lens unit, may be changed by the camera unit. As a result, a
function of changing the responsiveness of exposure control cannot
be realized.
SUMMARY OF THE INVENTION
[0007] According to an aspect of the present invention, an imaging
apparatus includes a sensor configured to photoelectrically convert
light from an object to output a signal, a selection unit
configured to select one of a first exposure control mode and a
second exposure control mode having an exposure changing amount per
unit time larger than that of the first exposure control mode, and
a controller configured to perform control to transmit diaphragm
control information generated based on the output signal from the
sensor, first information, and second information to a connected
lens unit, wherein the first information is about the exposure
control mode selected by the selection unit, and the second
information is speed information of a diaphragm unit corresponding
to the lens unit.
[0008] According to another aspect of the present invention, a lens
unit including a lens includes a diaphragm unit configured to
control exposure to adjust an incident light amount, a memory
configured to store speed information for driving the diaphragm
unit, and a controller configured to output the speed information
stored in the memory to an external apparatus, wherein the
controller controls the diaphragm unit based on diaphragm control
information periodically transmitted from the external
apparatus.
[0009] Further features and aspects of the present invention will
become apparent from the following detailed description of
exemplary embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a block diagram illustrating an exemplary
embodiment.
[0011] FIG. 2 is a flowchart 1 according to the exemplary
embodiment.
[0012] FIG. 3 is a flowchart 2 according to the exemplary
embodiment.
[0013] FIG. 4 illustrates a menu display example 1 for selecting
iris responsiveness.
[0014] FIG. 5 illustrates a menu display example 2 for selecting
iris responsiveness.
[0015] FIG. 6 illustrates a behavior where the iris changes.
[0016] FIG. 7 illustrates another behavior where the iris
changes.
DESCRIPTION OF THE EMBODIMENTS
[0017] A feature of the present invention is as follows. A lens
unit having a diaphragm unit for controlling exposure to adjust a
light amount to an imaging unit of a camera unit side includes a
storage unit configured to store diaphragm responsiveness
information regarding controllable responsiveness of the diaphragm
unit. The camera unit includes a generation unit configured to
generate diaphragm responsiveness information regarding
responsiveness of the diaphragm unit by taking at least the
diaphragm responsiveness information stored in the storage unit
into consideration. Thus, based on the diaphragm responsiveness
information generated by the generation unit of the camera unit
side, the responsiveness of the diaphragm unit of the lens unit
side can be controlled.
[0018] Exemplary embodiments of the present invention will be
described with reference to the drawings. FIG. 1 is a block diagram
illustrating an exemplary embodiment, which includes a lens unit
120 and a camera unit 121 in which the lens unit 120 is detachably
mounted. The lens unit 120 includes an imaging lens 101, an iris
102, which is a diaphragm unit for controlling exposure to adjust a
light amount to an imaging unit described below, an iris control
signal path 117 for controlling an opening/closing operation of the
iris 102, an iris F-number signal path 118 for electrically
transmitting an F-number of the iris 102, and a lens microcomputer
119 for performing system control of the lens unit 120.
[0019] The camera unit 121 includes an image sensor 103, such as a
charge-coupled device (CCD), which is an imaging unit for
converting an optical image of an object into an electric signal, a
correlated double sampling (CDS)/automatic gain control (AGC)
circuit 104, an analog/digital (A/D) converter 105 for converting
an analog video signal into a digital signal, a camera signal
processing circuit 106, a signal path 107 to a recorder unit, a
photometric value transmission path 108 for transmitting
integration data of luminance information generated by the camera
signal processing circuit 106 as a photometric value, a
transmission path 119 for transmitting a vertical synchronizing
signal (VD) generated by the camera signal processing circuit 106,
a menu key 110 for performing setting concerning functions of the
camera unit 121, an electronic viewfinder (EVF) 111 for displaying
selection items to perform setting concerning the functions of the
camera unit 121, a camera microcomputer 112 for performing system
control of the camera unit 121, a clock line 113 that is a
communication unit for performing transfer communication of various
pieces of information (clock) between the camera microcomputer 112
and the lens microcomputer 119, data lines 114 and 115 that are
communication units for performing transfer communication of
various pieces of information (data) between the camera
microcomputer 112 and the lens microcomputer 119. The data line 114
transmits data from the camera microcomputer 112 to the lens
microcomputer 119, and the data line 115 transmits data from the
lens microcomputer 119 to the camera microcomputer 112. The camera
unit 121 also includes a line 116 for transmitting a communication
VD.
[0020] A specific operation of the present exemplary embodiment
will be described.
[0021] Light from an object for generating a video signal is
image-formed by the lens 101, its light amount is adjusted by the
iris 102, and the light is subjected to photoelectric conversion at
the CCD 103. The video signal output from the CCD 103 enters the
CDS/AGC circuit 104 to be provided with a predetermined gain, and
is converted into a digital signal by the A/D converter 105 to
enter the camera signal processing circuit 106. The video signal is
subjected to camera signal processing at the camera signal
processing circuit 106 to be output and is transmitted to the
recorder unit via the signal path 107. The video signal
image-captured by the user can be checked on the EVF 111.
[0022] A photometric value for controlling exposure is generated by
the camera signal processing circuit 106 integrating a video
luminance signal, and entered into the camera microcomputer 112 via
the photometric value transmission path 108. A VD is generated in
the camera signal processing circuit 106, and entered into the
camera microcomputer 112 via a VD transmission path 109. The camera
microcomputer 112 communicates with the lens microcomputer 119, and
its timing is synchronized with the VD. The camera microcomputer
112 calculates, to perform exposure control by using the iris 102,
an F-number to be targeted by the iris 102 so that the photometric
value input via the photometric value transmission path 108 can
always coincide with a predetermined standard exposure value
correlated with a standard exposure state. The calculated F-number
is transmitted to the lens microcomputer 119 by using the clock
line 113, the data line 114, the data line 115, and the line
(communication synchronizing signal line) 116.
[0023] The lens microcomputer 119, to which the F-number of the
iris 102 is transmitted from the iris F-number signal path 118,
controls the iris 102 via the iris control signal path 117 so that
the transmitted F-number can consistently coincide with the target
F-number transmitted from the camera microcomputer 112 by
communication. When the user intentionally changes responsiveness
of the iris 102 by an user's operation from the outside,
responsiveness can be selected by selecting an iris responsiveness
selection screen displayed on the EVF 111 via the menu key
(selection unit) 110.
[0024] As described above, the camera unit that has the imaging
unit configured to convert the optical image of the object into the
electric signal includes the communication unit, the selection
unit, and the generation unit. The communication unit allows mutual
communication of information between the camera unit and the lens
unit, which is detachable from the camera unit and includes the
diaphragm unit and the storage unit configured to store the
diaphragm responsiveness information regarding the controllable
responsiveness of the diaphragm unit. The selection unit selects
responsiveness of exposure control including control by the
diaphragm unit, by an operation from the outside. The generation
unit generates diaphragm responsiveness information regarding the
responsiveness of the diaphragm unit from the responsiveness
selected by the selection unit and the diaphragm responsiveness
information transmitted via the communication unit and stored in
the storage unit. The lens unit detachable from the camera unit
includes the diaphragm unit, the communication unit, and the
storage unit. The lens unit may include the following control unit.
The control unit controls the responsiveness of the diaphragm unit
based on the diaphragm responsiveness information generated by the
generation unit of the camera unit side configured to generate the
diaphragm responsiveness information regarding the responsiveness
of the diaphragm unit from the responsiveness selected by the
selection unit and the diaphragm responsiveness information stored
in the storage unit.
[0025] Next, processing in a flowchart 1 according to the present
exemplary embodiment and illustrated in FIG. 2 will be described.
The flowchart 1 illustrates a sequence of communication from the
lens microcomputer 119 to the camera microcomputer 112. In step
S201, the camera microcomputer 112 detects a VD via the VD
transmission path 109, generates a communication synchronizing
signal (communicated via the communication synchronizing signal
line 116) from the VD, and starts bidirectional communication with
the lens microcomputer 119. Then, in step S202, the lens
microcomputer 119 sets information stored beforehand in the storage
unit of the lens microcomputer 119 and meaning that the iris 102 is
controllable by the camera unit 121. Then, in step S203, the lens
microcomputer 119 sets information (information about variable
range of responsiveness) about a controllable minimum speed of the
iris 102 and stored beforehand in the storage unit of the lens
microcomputer 119. Accordingly, the diaphragm responsiveness
information stored in the storage unit includes information about
whether the diaphragm unit is controllable by the camera unit via
the communication unit and the information about the variable range
of the controllable responsiveness of the diaphragm unit.
[0026] In step S204, the lens microcomputer 119 obtains an F-number
signal of the iris 102 via the iris F-number signal path 118 to set
it as F-number information. In step S205, the lens microcomputer
119 transmits the pieces of information set in steps S202, S203,
and S204 to the camera microcomputer 112.
[0027] Next, processing of a flowchart 2 according to the present
exemplary embodiment and illustrated in FIG. 3 will be
described.
[0028] The flowchart 2 illustrates a sequence of generating
information to be communicated from the camera microcomputer 112 to
the lens microcomputer 119. In step S301, the camera microcomputer
112 detects a VD via the VD transmission path 109 to determine
whether to start processing of step S302. In step S302, the camera
microcomputer 112 obtains a photometric value generated by the
cameral signal processing circuit 106 via the photometric value
transmission path 108. In step S303, the camera microcomputer 112
obtains F-number information of the iris 102 from the lens
microcomputer 119 via communication. In step S304, the camera
microcomputer 112 compares the photometric value obtained in step
S302 with an exposure target value preset therein, and calculates a
target position of the iris 102 from its difference value. For
example, when it is determined, as a result of the comparison of
the photometric value with the exposure target value, that the
photometric value is darker by 1 EV than the exposure target value,
the camera microcomputer 112 calculates an F-number brighter by 1
EV than a current F-number. Specifically, when the current F-number
is F4.0, a calculation result is to be F5.6. Similarly, when it is
determined, as a result of the comparison of the photometric value
with the exposure target value, that the photometric value is
brighter by 1 EV than the exposure target value, the camera
microcomputer 112 calculates an F-number darker by 1 EV than a
current F-number. Specifically, when the current F-number is F4.0,
a calculation result is to be F2.8.
[0029] Then, in step S305, the camera microcomputer 112 determines
whether responsiveness of the iris 102 is controllable by the
camera unit 121 based on the result of receiving the information
set in step S202 illustrated in FIG. 2 by the camera microcomputer
112. When it is determined that the responsiveness of the iris 102
is controllable (YES in step S305), in step S306, the camera
microcomputer 112 sets information about the responsiveness of the
iris 102 selected and set beforehand by the user via the menu
screen to be transmitted to the lens microcomputer 119. The
information about the responsiveness of the iris 102 is defined by,
for example, a light amount to be changed per unit time. When it is
not determined that the responsiveness of the iris 102 is
controllable (NO in step S305), in step S307, the camera
microcomputer 112 sets the target position of the iris 102
calculated in step S304 to be transmitted to the lens microcomputer
119. The diaphragm responsiveness information generated by the
generation unit in the camera microcomputer 112 is generated in
view of information about the variable range of the controllable
responsiveness of the diaphragm unit and stored in the storage
unit. Then, in step S308, the camera microcomputer 112 transmits
the pieces of information set in steps S306 and S307 to the lens
microcomputer 119.
[0030] Next, referring to FIGS. 4 and 5, an example of a method for
changing the responsiveness of the iris 102 via the menu screen by
the user will be described. FIG. 4 illustrates the menu screen for
changing the responsiveness of the iris 102 and which is displayed
on the EVF 111. In the responsiveness selection menu of the iris
102, the user can select responsiveness of the iris 102 from three
modes, i.e., a high-speed mode, a medium-speed mode, and a
low-speed mode. The user can select responsiveness of the iris 102
by using the menu key 110 while the user watches the screen
displayed on the EVF 111. FIG. 5 illustrates a display example
indicating to the user that the responsiveness of the iris 102
cannot be switched from the responsiveness selection menu of the
iris 102. Which of the example illustrated in FIG. 4 and the
example illustrated in FIG. 5 is displayed is determined by
determining whether the responsiveness of the iris 102 is
controllable by the camera unit 121 in step S305 of the flowchart 2
illustrated in FIG. 3. Specifically, when the responsiveness of the
iris 102 is controllable by the camera unit 121, as illustrated in
FIG. 4, the screen menu enabling switching among the high-speed
mode, the medium-speed mode, and the low-speed mode from the iris
responsiveness selection menu is displayed. When the responsiveness
of the iris 102 is not controllable by the camera unit 121, as
illustrated in FIG. 5, inhibition of a change from the iris
responsiveness selection menu is displayed. In other words, when
the diaphragm unit cannot be controlled by the camera unit,
selection of responsiveness by the selection unit is inhibited.
[0031] Next, referring to FIG. 6, a behavior where the iris 102
changes when the responsiveness of the iris is changed on the iris
responsiveness selection menu will be described. FIG. 6 illustrates
the behavior where the F-number changes from F8.0 to F2.8 with the
passage of time in each of the high-speed mode, the medium-speed
mode, and the low-speed mode. In FIG. 6, the horizontal axis
indicates time, and the vertical axis indicates an F-number. As can
be understood from FIG. 6, F2.8 is reached within a shorter time in
the high-speed mode than in the medium-speed mode. It takes longer
to reach F2.8 in the low-speed mode than in the medium-speed mode.
A specific flow changing the responsiveness of the iris 102 will be
described. When the high-speed mode is selected on the iris
responsiveness selection menu in step S306 of the flowchart 2 in
FIG. 3, information for changing a light amount by 1.5 EV per 0.1
second is generated, and transmitted to the lens microcomputer 119.
Similarly, when the medium-speed mode is selected on the iris
responsiveness selection menu, information for changing the light
amount by 0.75 EV per 0.1 second is generated, and transmitted to
the lens microcomputer 119. Similarly, when the low-speed mode is
selected on the iris responsiveness selection menu, information for
changing the light amount by 0.5 EV per 0.1 second is generated,
and transmitted to the lens microcomputer 119. The lens
microcomputer 119 receives the information for changing the light
amount per unit time as described above, and then controls the iris
102 via the iris control signal path 117.
[0032] Next, referring to FIG. 7, a case where the controllable
responsiveness of the iris 102 can be controlled faster than that
described above and referring to FIG. 6 will be described. As in
the case of FIG. 6, FIG. 7 illustrates a behavior where the
F-number changes from F8.0 to F2.8 with the passage of time in each
of the high-speed mode, the medium-speed mode, and the low-speed
mode. In FIG. 7, the horizontal axis indicates time, and the
vertical axis indicates an F-number. A difference from FIG. 6 is in
that time for reaching F2.8 from F8 is shorter in each of the
high-speed mode, the medium-speed mode, and the low-speed mode. A
specific flow of changing the responsiveness of the iris 102 will
be described. In step S203 of the flowchart 1 in FIG. 2,
information regarding the minimum speed at which the iris 102 can
operate is set. In step S205, the information is transmitted to the
camera unit 121. In other words, when the iris 102 cannot be
controlled slow due to its performance, information regarding the
minimum speed, at which an operation can be ensured, is transmitted
to the camera unit 121. In step S306 of the flowchart 2 in FIG. 3,
responsiveness of the iris 102 is set. At this time, the
responsiveness must be set in view of information about a
controllable minimum speed of the iris 102. Specifically, when, in
step S203 of the flowchart 1 in FIG. 2, information about changing
of the light amount by 0.5 EV per 0.1 second is set as information
regarding the minimum speed at which the iris 102 can operate, an
operation is performed as follows. When the low-speed mode is
selected on the iris responsiveness selection menu, information
indicating that the light amount is to be changed by at least 0.5
EV or more per 0.1 second must be generated to be transmitted to
the lens microcomputer 119.
[0033] The exemplary embodiment of the present invention has been
described. However, the present invention is not limited to the
exemplary embodiment. Various embodiments without departing from
the gist of the present invention are within the invention. Some
parts of the exemplary embodiment can be arbitrarily combined.
[0034] According to the exemplary embodiment of the present
invention, the information about the controllable responsiveness
(light amount change per unit time) of the diaphragm unit and
stored in the lens unit can be communicated from the lens unit to
the camera unit. This enables the camera unit to obtain information
about the variable range of the controllable responsiveness
according to the mounted lens unit. As a result, the camera unit
can set responsiveness of the diaphragm unit within the variable
range of the responsiveness. Thus, a system capable of realizing a
function of selecting responsiveness of the diaphragm unit from,
for example, the high-speed mode, the medium-speed mode, and the
low-speed mode can be provided.
[0035] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
* * * * *