JP2009282239A - Illuminator for photography, and photographing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator for photography by which a light controllable distance in photography is obtained in detail. <P>SOLUTION: The illuminator for photography (200) includes: a light emitting part (10) emitting illuminating light for photography when performing photography by using a photographing device (100); a shutter information acquiring part (41) acquiring information on shutter totally opening time when all the imaging range of an imaging part (110) included in the photographing device is simultaneously exposed to subject light when performing photography; a light emitting efficiency decision part (42) obtaining light emitting efficiency showing a rate of an effective emitted light quantity contributing to exposure during the shutter totally opening time to the total emitted light quantity of illuminating light that the light emitting part can emit when emitting the illuminating light; and an arithmetic calculation part (43) arithmetically calculating the light controllable distance in photography based on the light emitting efficiency obtained by the light emitting efficiency decision part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photographing illumination device and a photographing device.

Dimmable distance at the time of shooting based on various information such as guide number information, aperture value information, imaging sensitivity, etc. Is known (see, for example, Patent Document 1).
JP-A-60-165627

This type of illumination device for photographing is desired to be able to calculate the dimmable distance at the time of photographing in more detail.
The subject of this invention is providing the illuminating device for imaging | photography which can obtain | require the dimmable distance at the time of imaging | photography in detail, and an imaging device.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 is a light emitting unit (10) that emits illumination light for photographing when photographing using the photographing device (100), and an imaging unit provided in the photographing device when performing the photographing. (110) A shutter information acquisition unit (41) that acquires information on a shutter full-open time for exposing subject light to the entire surface of the imaging range at the same time, and the light emitting unit can emit light when emitting the illumination light. A light emission efficiency determining unit (42) for obtaining a light emission efficiency indicating a ratio of an effective light emission amount contributing to exposure during the shutter full opening time with respect to a total light emission amount, and the photographing based on the light emission efficiency obtained by the light emission efficiency determination unit It is an imaging illuminating device (200) provided with the calculating part (43) which calculates the light controllable distance at the time.

According to a second aspect of the present invention, in the photographing illumination device according to the first aspect, in addition to the luminous efficiency, the calculation unit (43) guides the light emitting unit (10) when emitting the illumination light. The photographing illumination device (200) is characterized in that the dimmable distance is calculated based on a number and a diaphragm value of a diaphragm unit (180) provided in the photographing device (100).
According to a third aspect of the present invention, in the photographing illumination device according to the second aspect, the calculation unit (43) acquires information on imaging sensitivity of the imaging unit (110) at the time of shooting, and the guide number, The photographing illumination device (200), wherein the dimmable distance is calculated based on an aperture value, the light emission efficiency, and the imaging sensitivity.
According to a fourth aspect of the present invention, in the photographing illumination device according to any one of the first to third aspects, the display unit (30) displays the dimmable distance obtained by the calculation unit (43). The illumination device for photography (200) characterized by comprising.
According to a fifth aspect of the present invention, in the photographing illumination device according to any one of the first to fourth aspects, light emission efficiency data relating to the light emission efficiency is prepared in advance for each of the shutter full-open times different from each other. The light emission efficiency determination unit (42) is the photographing illumination device (200) characterized in that the light emission efficiency is obtained by referring to the light emission efficiency data.
According to a sixth aspect of the present invention, in the illumination device for photographing according to any one of the first to fifth aspects, the shutter information acquisition unit (41) includes a travel time of the shutter curtain (131, 132) and The photographing illumination device (200) is characterized in that information relating to a shutter time at the time of photographing set in advance is acquired, and the shutter fully open time is calculated from the running time of the shutter curtain and the shutter time.
A seventh aspect of the present invention is a photographing apparatus (1) comprising the photographing illumination device (200) according to any one of the first to sixth aspects.
Note that the configuration described with reference numerals may be modified as appropriate, and at least a part of the configuration may be replaced with another component.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device for imaging | photography which can obtain | require the dimmable distance at the time of imaging | photography in detail, and an imaging device can be provided.

Hereinafter, a camera system including an embodiment of a photographing illumination device to which the present invention is applied will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a camera system according to an embodiment.
The camera system 1 includes a camera 100 and a photographing illumination device 200 (hereinafter referred to as illumination device 200).

The camera 100 includes a camera body 101 and an interchangeable lens barrel 102 that is detachably attached to the camera body 101.
The camera body 101 includes an image sensor 110, a signal processing circuit 120, a shutter unit 130, a mirror unit 140, a photometric sensor 150, an AE (Auto Exposure) control unit 160, a communication unit 170, and the like.
The image sensor 110 is an image sensor including a photoelectric conversion element that converts subject light into an electrical analog signal and outputs the signal. As the image sensor 110, a complementary metal oxide semiconductor (CMOS), a charge coupled device (CCD), or the like can be used.

  The signal processing circuit 120 includes an amplification circuit that amplifies the analog signal output from the image sensor 110, an A / D converter that converts the amplified analog signal into a digital signal, and the like (amplification circuit, A / D). (The converter is not shown). Image data generated by the signal processing circuit 120 is recorded in a storage medium 121 such as a flash memory.

The shutter unit 130 adjusts the exposure time of the subject light with respect to the image sensor 110. The shutter unit 130 is a known focal plane shutter disposed on the front side of the subject light incident direction with respect to the imaging surface of the image sensor 110.
The shutter unit 130 travels a similar light shielding member referred to as a rear curtain 132 after traveling a light shielding member referred to as a front curtain 131, and an image pickup device is detected depending on the timing of start of travel of these light shielding members. The exposure time for 110 is adjusted.

The shutter unit 130 exposes the imaging surface of the imaging device 110 when the closed front curtain 131 starts running and shifts to the open state, thereby exposing subject light to the imaging surface. In addition, the shutter unit 130 starts to travel after the set time referred to as shutter speed (or shutter speed) elapses after the front curtain 131 starts traveling, and then starts to travel and closes. Thus, the subject light traveling toward the image sensor 110 is blocked.
In the first curtain 131 and the second curtain 132, the time from the start to the end of travel (hereinafter referred to as the curtain travel time) is substantially constant regardless of the set shutter time. The curtain travel time varies depending on the type of camera body 101 (the type of shutter unit 130 and the size of the image sensor 110). The curtain travel time of the shutter unit 130 of this embodiment is, for example, 2000 μsec (2. 0 msec).

The mirror unit 140 guides subject light to a photometric sensor 150 described later and an optical viewfinder device (not shown). The mirror unit 140 guides the subject light to the photometric sensor 150 or the like by a main mirror disposed on the optical path of the subject light during framing, and retracts from the optical path of the subject light during imaging.
The photometric sensor 150 passes through the photographing lens L of the interchangeable lens barrel 102 (Through The
Lens) and an image sensor that receives subject light reflected by the mirror unit 140.

  The AE control unit 160 is a part that automatically determines the shutter speed at the time of shooting, the aperture value, the imaging sensitivity of the image sensor 110, the light emission amount of the illumination device 200 at the time of shooting, and the like based on the output of the photometric sensor 150. . The signal processing circuit 120 described above amplifies the output of the imaging element 110 according to the imaging sensitivity determined by the AE control unit 160. However, the camera system 1 can also set these parameters manually by a photographer or the like.

The communication unit 170 is a part that performs electrical communication with the communication unit 20 provided in the lighting device 200 described later, and is determined by the AE control unit 160 for the lighting device 200 (or manually input by a photographer or the like). Information relating to various parameters such as shutter time (SS value), aperture value (F value), imaging sensitivity (ISO value), and exposure correction amount (ΔEv) of the image sensor 110 is provided to the illumination device 200.
In addition, the communication unit 170 transmits information related to the curtain travel time of the front curtain 131 and the rear curtain 132 provided in the shutter unit 130 to the lighting device 200.

The interchangeable lens barrel 102 includes a photographic lens L that guides subject light to an image sensor 110 provided in the camera body 101, and a diaphragm device 180 that adjusts the amount of subject light that passes through the photographic lens L by a plurality of diaphragm blades. I have.
The camera body 101 (or the interchangeable lens barrel 102) includes an actuator (not shown) that drives the aperture device 180, and is used at the time of photographing obtained by the AE control unit 160 (or manually set by a photographer or the like). Based on the aperture value, the aperture device 180 is driven during shooting.

The illuminating device 200 irradiates photographic illumination light toward a subject or the like during photographing, and is detachably attached to the camera body 101. The camera body 101 is capable of electrical communication with the lighting device 200 via an electrical contact (not shown) with the lighting device 200 attached.
The illumination device 200 includes a light emitting unit 10, a communication unit 20, a display unit 30, a control unit 40, and the like.

  The light emitting unit 10 includes a xenon lamp that emits a flash as illumination light for photographing, a diffuser that diffuses the flash emitted by the xenon lamp, and a zoom mechanism that changes the illumination angle of the illumination light in conjunction with the focal length of the photographing lens L. (Diffusion plate and zoom mechanism are not shown). The light emitting element that emits illumination light is not limited to a xenon lamp, and for example, a light emitting diode or the like can be used.

The communication unit 20 is a part that performs electrical communication with the communication unit 170 provided in the camera body 101, and information related to various parameters such as the shutter speed at the time of shooting, the aperture value, and the imaging sensitivity of the image sensor 110 from the camera body 101. To get.
The display unit 30 includes, for example, a liquid crystal panel, and a display surface is provided on a surface facing the photographer at the time of shooting. The display screen of the display unit 30 displays imaging sensitivity, aperture value, focal length of the taking lens L, and the like acquired from the camera body 103.

The control unit 40 is a part that comprehensively controls the communication unit 20, the display unit 30, and the like described above, and includes a shutter full open time calculation unit 41, a light emission efficiency determination unit 42, and a calculation unit 43.
The shutter full-open time calculation unit 41 acquires information about the shutter time at the time of shooting and information about the curtain travel time of the front curtain 131 and the rear curtain 132 provided in the shutter unit 130 via the communication unit 20. To calculate the shutter fully open time.

Here, the shutter fully open time means a time during which subject light is simultaneously exposed to the entire imaging range of the imaging device 110 provided in the camera body 101 when shooting. The entire surface of the imaging range means the entire imaging surface when shooting is performed using the entire imaging surface of the image sensor 110, and only a part of the imaging surface (for example, the central portion of the imaging surface). When shooting is performed using this, it means a part of the imaging surface.
Specifically, for example, when the shutter time at the time of shooting is set to 1/200 second (5000 μsec), the curtain running time is 2000 μsec as described above, so the shutter fully open time is 3000 μsec. Become.

The light emission efficiency determination unit 42 determines the light emission efficiency indicating the ratio of the light amount (effective light emission amount) that actually contributes to the exposure with respect to the total light emission amount that the light emitting unit 10 can emit when emitting the illumination light. Part.
Hereinafter, the effective light emission amount will be described.

FIG. 2 is a diagram showing a change in the amount of illumination light (flash) emitted by the illumination device shown in FIG.
In FIG. 2, (a) and (b) show cases where the shutter time is different, and (a) shows a case where the shutter time is longer than (b). However, in both (a) and (b), the change in the amount of illumination light itself is the same.
As shown in FIGS. 2A and 2B, when flash emission is performed, the flash emitted from the xenon lamp increases after the start of emission and after the emission reaches a peak after the start of emission. The amount of light emission decreases with the passage of time.

When performing flash emission, the camera body 101 sends a light emission start signal to the illumination device 200 via the communication unit 170 when the travel of the front curtain 131 of the shutter unit 130 is completed and the shutter unit is fully opened. Output. In response to this, the illuminating device 200 starts flash emission.
Then, the camera body 101 starts traveling of the front curtain after the shutter time set in advance elapses after starting the traveling of the front curtain. The camera body 101 outputs a light emission stop signal to the lighting device 200 via the communication unit 170 in conjunction with the start of running of the rear curtain. In response to this, the lighting device 200 stops the light emission. Note that, if the light emission stop signal is not input, the lighting apparatus 200 of the present embodiment is configured to complete the light emission (light quantity = 0), for example, after about 8 msec has elapsed since the start of light emission.

Therefore, when the shutter fully open time is less than 8 msec, the light emission amount actually contributing to the exposure (region A in the graph shown in FIG. 2) is the total light emission amount that can be emitted (region A + region B in the graph shown in FIG. 2). Only a part of them.
The light emission efficiency means the ratio of the effective light emission amount to the total light emission amount (A / (A + B)) described above, and varies depending on the set shutter time (that is, the shutter full open time).
In the illuminating device 200 of this embodiment, luminous efficiency data relating to luminous efficiency is recorded in the memory 50 in advance for each different shutter full opening time, and the light emission efficiency determining unit 42 calculates the shutter full opening time calculated by the shutter full opening time calculating unit 41. Based on this, the luminous efficiency is determined by referring to the luminous efficiency data.

Table 1 is a table showing the luminous efficiency of illumination light for each different shutter full opening time.
The data shown in Table 1 is unique to the lighting device 200, is created by collecting data in advance by a test, and is stored in the memory 50.

An example will be described with reference to Table 1. If the shutter fully open time is, for example, 8000 μsec or more (when the shutter speed is low), all of the emitted illumination light contributes to the exposure. Such a case is referred to as having a luminous efficiency of 100%.
It can also be seen that the luminous efficiency is about 80% when the shutter fully open time is, for example, 2600 μsec.
On the other hand, when the shutter fully open time is, for example, 300 μsec (when the shutter speed is high), the light emission is stopped immediately after the light emission, so that the light emission efficiency is reduced to about 15%.

The calculating unit 43 calculates the luminous efficiency obtained by the luminous efficiency determining unit 42, the guide number (GN) of the light emitting unit 10 when emitting illumination light, the aperture value (F value) of the aperture device 180, and the imaging element 110. This is a part for calculating the dimmable distance at the time of shooting based on the imaging sensitivity (ISO value). The light controllable distance means the upper limit of the distance over which the effect of the illumination light irradiated by the illumination device 200 when shooting using the camera 1 is performed. Can be prevented from becoming unclear due to insufficient light quantity.
Hereinafter, a specific description will be given assuming that the imaging sensitivity is ISO 100 and the maximum guide number is 40 (GN40).
For example, if the shutter fully open time is 8000 μsec or more, it can be seen from Table 1 that all (100%) of the total light emission that can be emitted contributes to exposure, so that the light emitting unit 10 can emit light with the maximum guide number. Become. In this case, for example, if the aperture value at the time of shooting is 4 (F4), the dimmable distance (substantially the longest possible shooting distance) is 10 m (40 ÷ 4).

On the other hand, for example, when the shutter speed is 2500 μsec, the shutter fully open time is 500 μsec, and therefore the luminous efficiency is 0.255 from Table 1. That is, about 25 to 26% of the total emitted light amount that can emit light actually contributes to the exposure.
Since the light emission amount of the light emitting unit 10 is proportional to the square of the guide number, if the maximum guide number (GN40) is multiplied by this luminous efficiency and squared, the guide number (effective guide number) at the corresponding shutter speed is obtained. Can be sought.
In the above example, since the maximum guide number is GN40 and the luminous efficiency is 0.255, the guide number (effective guide number) is about 20. Therefore, when the aperture is F4, the dimmable distance is about 5 m (20 ÷ 4).

Here, even if the shutter 100 is fully open and the aperture value is fixed, the camera 100 can perform shooting with a smaller amount of light if the imaging sensitivity of the imaging device 110 is increased. Therefore, even if the luminous efficiency is the same, the upper limit of the dimmable range changes if the imaging sensitivity is increased. In the above example, for example, if the imaging sensitivity is ISO400, the effective guide number is about 40 even when the shutter fully open time is 500 μsec, and thus the dimmable distance is 10 m.
Note that the above-described effective guide number calculation (multiplication / division) is performed by logarithmic calculation (addition / subtraction) with a base of 2 in consideration of the load on the microcomputer performing the calculation.

The dimmable distance calculated by the calculation unit 43 is displayed on the display unit 30.
FIG. 3 is a diagram illustrating an example of a display screen of a display unit provided in the lighting device illustrated in FIG. 1.
As shown in FIG. 3, the display screen of the display unit 30 includes a dimmable range 30a (0.6-5.0 m) at the time of shooting, an imaging sensitivity 30b (ISO 400), and a focal length 30c (24 mm) of the shooting lens L. ), An aperture value 30d (F4.0) and the like are displayed. The lower limit of the dimmable range is constant regardless of the shutter speed if the illumination angle of illumination light is constant.

Next, the control performed by the control unit 40 provided in the lighting device 200 will be described step by step using a flowchart.
FIG. 4 is a flowchart illustrating the control performed by the control unit provided in the lighting device.

(Step S01: Acquisition of travel time information for the first and second curtains)
Since the travel time of the front curtain 131 and the rear curtain 132 of the shutter unit 130 varies depending on the type of the camera body 101, the control unit 40 first acquires these pieces of information from the camera body 101 and proceeds to step S02.
(Step S02: Acquisition of shutter speed, aperture value, imaging sensitivity information)
The camera body 101 determines the shutter speed, aperture value, imaging sensitivity, and the like during shooting based on the output of the photometric sensor 150 or the input operation of the photographer.
The control unit 40 acquires these pieces of information from the camera body 101 via the communication unit 20, and proceeds to step S03.

(Step S03: Maximum GN information acquisition)
The control unit 40 acquires the maximum guide number information from the light emitting unit 10 based on the illumination angle of illumination light defined by the zoom mechanism, and proceeds to step S04.
(Step S04: shutter full open time calculation)
Based on the travel time of the shutter curtain acquired in step S01 and the shutter time obtained in step S02, the controller 40 calculates the shutter full open time based on the shutter second time acquired in step S02, and proceeds to step S05.

(Step S05: Determination of luminous efficiency)
The control unit 40 determines the light emission efficiency corresponding to the shutter fully open time obtained in step S04 with reference to the data (Table 1) stored in the memory 50 by the light emission efficiency determination unit 42, and proceeds to step S06.
(Step S06: Effective GN calculation)
In the control unit 40, the calculation unit 43 calculates an effective guide number based on the maximum guide number obtained in step S03 and the light emission efficiency obtained in step S04, and the process proceeds to step S07.

(Step S07: Dimmable distance calculation)
The control unit 40 calculates a dimmable distance based on the aperture value and imaging sensitivity obtained in step S02 and the effective guide number obtained in step S06, and proceeds to step S08.
(Step S08: Dimmable range display)
The control unit 40 displays the dimmable range including the dimmable distance obtained in step S07 on the display unit 30 and ends the process.

According to the illumination device of the embodiment described above, the following effects can be obtained.
(1) When calculating the light controllable distance, the light emission efficiency of the light emitting unit 10 that changes depending on the shutter speed (shutter fully open time) is taken into account, so that a more accurate light controllable distance can be calculated. Accordingly, it is possible to prevent an image with insufficient light quantity from being photographed even though the photographer photographed according to the display on the display unit 30.
(2) Since the dimmable range including the dimmable distance is displayed on the display unit 30, the photographer increases the imaging sensitivity of the image sensor 110 when there is a risk of insufficient light quantity, or illumination with a larger light emission amount. It is possible to take measures such as replacing the device.
(3) Since the luminous efficiency data is prepared in advance for each different shutter full-open time, the calculation processing when obtaining the dimmable distance can be speeded up.

[Deformation]
The present invention is not limited to the embodiment described above, and various modifications and changes as shown below are possible, and these are also included in the technical scope of the present invention.
(1) In the embodiment, the lighting device is a so-called clip-on type that is detachably attached to the camera body. However, the lighting device is not limited thereto, and may be built in the camera body.
(2) In the embodiment, the photographing apparatus is a digital camera provided with an image sensor. However, the present invention is not limited thereto, and may be a film camera provided with a silver salt film as an image pickup unit.
(3) In the lighting device of the embodiment, the dimmable range is displayed on the display unit provided in the lighting device. May be. Further, the dimmable range may not be displayed, and notification may be made by voice or the like.
(4) In the lighting device of the embodiment, the effective guide number obtained by correcting the maximum guide number by the light emission efficiency is obtained, but other parameters in addition to the light emission efficiency (for example, the voltage of the capacitor that is the power source of the xenon lamp) The guide number may be corrected based on the above.
(5) In the embodiment, the dimmable distance is displayed on the display unit of the lighting device to provide information to the photographer as to whether or not photographing is possible. For example, when the influence of the illumination light does not reach the subject Further, control for automatically increasing the imaging sensitivity of the image sensor on the camera body side, control for disabling shooting, or the like may be performed.
(6) In the embodiment, the controller of the lighting device calculates the shutter full open time. However, the present invention is not limited to this, and the shutter full open time may be calculated on the camera body side and transmitted to the lighting device.
(7) In the embodiment, the luminous efficiency is obtained from data prepared in advance (Table 1). However, the present invention is not limited to this. For example, the luminous efficiency may be calculated based on the following equation.
Luminous efficiency = at ³ + bt ² + ct + d
(A, b, c, d: constant, t: time)

It is a block diagram which shows the camera system of embodiment. It is a figure which shows the change of the light emission amount of the illumination light which the illuminating device shown in FIG. 1 light-emitted. It is a figure which shows an example of the display screen of the display part with which the illuminating device shown in FIG. 1 was equipped. It is a flowchart which shows the control which the control part with which the illuminating device was equipped performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Light emission part: 30 Display part: 40 Control part: 41 Shutter full open time calculating part: 42 Luminous efficiency determination part: 43 calculating part: 100 Camera: 110 Image pick-up element: 200 Illuminating device

Claims (7)

A light-emitting unit that emits illumination light for photographing when photographing using the photographing device;
A shutter information acquisition unit that acquires information on a shutter full-open time for exposing subject light simultaneously to the entire imaging range of the imaging unit provided in the imaging device when performing the imaging;
A light emission efficiency determining unit for obtaining a light emission efficiency indicating a ratio of an effective light emission amount that contributes to exposure during the shutter full-open time with respect to a total light emission amount that the light emitting unit can emit when emitting the illumination light; and
A photographing illumination device comprising: a computing unit that computes a dimmable distance at the time of photographing based on the luminous efficiency obtained by the luminous efficiency determining unit. The illumination device for photographing according to claim 1,
In addition to the light emission efficiency, the calculation unit calculates the dimmable distance based on the guide number of the light emitting unit when emitting the illumination light and the aperture value of the aperture unit provided in the photographing apparatus. An illumination device for photographing characterized by computing. The illumination device for photographing according to claim 2,
The calculation unit acquires information related to the imaging sensitivity of the imaging unit at the time of shooting, and calculates the dimmable distance based on the guide number, the aperture value, the light emission efficiency, and the imaging sensitivity. A lighting device for photographing. The illuminating device for photographing according to any one of claims 1 to 3,
A photographic illumination device comprising: a display unit that displays the dimmable distance obtained by the arithmetic unit. In the illuminating device for photographing according to any one of claims 1 to 4,
Luminous efficiency data relating to the luminous efficiency is prepared in advance for each different shutter full opening time,
The illuminating efficiency determining unit obtains the luminous efficiency by referring to the luminous efficiency data. In the illuminating device for photographing according to any one of claims 1 to 5,
The shutter information acquisition unit acquires information relating to the travel time of the shutter curtain and a preset shutter time at the time of shooting, and calculates the shutter full open time from the travel time of the shutter curtain and the shutter time. An illumination device for photographing. A photographing apparatus comprising the photographing illumination device according to any one of claims 1 to 6.

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