JP4074799B2 - camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a camera that performs photographing by capturing subject light incident via a photographing optical system.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a camera for taking a photograph on a photographic film that includes a photographing optical system with a variable focal length, for example, a zoom lens. A camera equipped with a zoom lens is more versatile than a camera equipped with a single-focus lens, such as the ability to change the image magnification by changing the focal length, so that a far-field subject can be photographed with a so-called zooming function. Framing is possible.
[0003]
By the way, the maximum aperture of a diaphragm in a camera equipped with a zoom lens is determined based on the focal length when the zoom lens is set to a long focal length and the F value of the zoom lens when the camera is designed. However, when the zoom lens is set to a short focal length in the camera, when taking a picture with the aperture opened to the maximum aperture, the amount of light at the peripheral portion is lower than the amount of light at the center in the photographic angle of view. The periphery of the photographed picture, especially the four corners, will be dark. It is known that this decrease in the amount of peripheral light can be solved by reducing the aperture by about one to two steps from the open state.
[0004]
Therefore, in a camera equipped with a zoom lens, when the zoom lens is set to a short focal length, by adopting an aperture that includes an aperture restriction mechanism that regulates to an aperture that is narrower than the maximum aperture described above, This eliminates the problem of reduced peripheral light intensity.
[0005]
Regarding the point of changing the aperture, there is one that changes the aperture according to the result of preliminary shooting (see, for example, Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-150598
[Problems to be solved by the invention]
Here, in general, in a camera equipped with a photographing lens having a focal length of about 30 mm, when a shutter speed is 1/30 seconds, photographing is not performed without using a fixing device such as a tripod, that is, without being affected by camera shake. Is said to be the slowest shutter speed.
[0008]
However, in order to prevent the above-described decrease in the amount of peripheral light, in a camera equipped with a diaphragm aperture restriction mechanism, the aperture is restricted to an aperture that is narrower than the maximum aperture by setting the zoom lens to a short focal length. If you take a photo with, the picture will be dark. In such a case, shooting a bright picture can be realized by slowing down the shutter speed. However, if the shutter speed is slowed down to 1/30 seconds or less, a fixing device such as a tripod is used to prevent camera shake. Is required.
[0009]
SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a camera capable of shooting a bright depiction when shooting in a dark place.
[0010]
[Means for Solving the Problems]
The first camera of the present invention that achieves the above object is:
When the photographic optical system with variable focal length and the photographic optical system is set to a focal length less than or equal to a predetermined focal length, the maximum aperture is set to a predetermined long focal length. An aperture controlled by the second maximum aperture that is narrower than the first maximum aperture, and a camera that performs imaging by capturing subject light incident through the imaging optical system and the aperture,
A metering unit for measuring the field luminance;
When the field brightness measured by the photometry unit is a field brightness that is equal to or lower than a predetermined field brightness, the aperture restriction of the stop is released, and the stop is moved to the object measured by the photometry unit. According to the field brightness, an aperture restriction release unit is provided which is set to an opening between the first maximum opening including the first maximum opening and the second maximum opening.
[0011]
In general, when shooting in a dark place such as when shooting a night view, there is almost no problem with a decrease in the amount of peripheral light. The present invention has been completed in view of this point. When the field luminance is equal to or lower than a predetermined field luminance, the aperture restriction of the diaphragm is canceled, and the aperture is measured by the photometric unit. The aperture is set between the maximum aperture including the maximum aperture when the photographic lens is set to a predetermined long focal length in accordance with the field brightness and the maximum aperture narrowed from the maximum aperture. Therefore, a camera capable of shooting a bright picture without using a fixing device is realized in shooting in a dark place where reduction in the amount of peripheral light is not a problem.
[0012]
Here, the aperture restriction canceling unit may set the aperture to the first maximum aperture when the aperture restriction of the aperture is canceled.
[0013]
When the first maximum opening is set, a mechanism for restricting to an intermediate opening between the first maximum opening and the second maximum opening is unnecessary, and the structure of the diaphragm is simplified correspondingly.
[0014]
The aperture restriction canceling unit cancels the aperture restriction of the aperture when the field luminance measured by the photometry unit is equal to or less than a predetermined field luminance set within a range of LV6 or less. It is also a preferred embodiment.
[0015]
In this way, the field luminance for canceling the aperture restriction is set to a field luminance set within a range of LV6 or less, which is darker than the field luminance at the time of shooting indoors. It is preferable.
[0016]
In addition, it is preferable that this camera is a camera in which a photographic photosensitive member is loaded and photographing is performed on the loaded photographic photosensitive member.
[0017]
The present invention focuses on the fact that there is no problem in the case of night scene shooting even with an aperture opening where the decrease in peripheral light amount is noticeable when shooting in a bright place. In the case of a digital camera, Although there is a means for correcting the decrease in the peripheral light amount by image processing on the image data, the decrease in the peripheral light amount cannot be corrected in the case of a type of camera that shoots on a photographic photosensitive member. Is suitable for a camera of a type that performs photographing on a photographic photosensitive member. However, even in the case of a digital camera, by applying the present invention, there is an advantage that it is not necessary to correct the decrease in the amount of peripheral light by image processing.
[0018]
The second camera of the present invention that achieves the above object is:
A photographing optical system, and a diaphragm that opens to a predetermined first maximum aperture, the maximum aperture being restricted to a predetermined second maximum aperture that is narrower than the first maximum aperture; In a camera that takes a picture by capturing the subject light incident through the photographing optical system and the diaphragm,
A metering unit for measuring the field luminance;
When the field brightness measured by the photometry unit is a field brightness that is equal to or lower than a predetermined field brightness, the aperture restriction of the stop is released, and the stop is moved to the object measured by the photometry unit. According to the field brightness, an aperture restriction release unit is provided which is set to an opening between the first maximum opening including the first maximum opening and the second maximum opening.
[0019]
According to the second camera, when the field luminance is equal to or lower than a predetermined field luminance, the aperture restriction of the diaphragm is canceled, and the diaphragm is set according to the field luminance measured by the photometry unit. Since the aperture is set between the maximum aperture and the maximum aperture that is narrower than the maximum aperture, the decrease in the amount of light in the surroundings is suppressed in shooting in bright locations, and fixed in shooting in the dark. The range in which bright depictions can be taken without using tools is expanded.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0021]
FIG. 1 shows a camera equipped with a zoom lens that is an example of a variable focal length photographing optical system according to an embodiment of the present invention, and a zoom lens barrel that supports the zoom lens is housed in the camera body. FIG. 2 is a perspective view showing the maximum extended state in which the zoom lens barrel is extended to the maximum extent, which is the camera shown in FIG.
[0022]
A camera 10 shown in FIGS. 1 and 2 is a camera that takes a photograph on a photographic film (not shown).
[0023]
A zoom lens barrel 11 having a zoom lens 11 a therein is provided at the center of the front surface of the camera 10. In addition, a flash emission window 12, a finder objective window 13, an AF projection window 14a incorporating a light emitting element for autofocus (AF), and an AF projection window 14a are projected on the upper front of the camera 10. Light field intensity (Light Value: hereinafter referred to as “Light Value”) that guides light to the AF light receiving window 14b including a light receiving element that receives the light reflected and returned from the subject and the built-in exposure adjustment AE sensor 151. AE light receiving window 15 for measurement) is provided.
[0024]
A shutter button 16 and a rotary select dial 24 are provided on the upper surface of the camera 10. By turning the select dial 24 and adjusting the index printed on the select dial 24 to the mode printed on the upper surface of the camera 10, the program mode (P) is set in addition to the OFF state shown in FIGS. Can be switched.
[0025]
FIG. 3 is a perspective view of the camera shown in FIGS.
[0026]
A finder eyepiece window 17 and a zoom operation lever 18 are provided on the back of the camera 10. When one of the operation portions 18a of the zoom operation lever 18 is pushed, the zoom lens barrel 11 moves from the retracted state shown in FIG. 1 toward the maximum extended state shown in FIG. When the other operation portion 18b is pressed, the zoom lens barrel 11 moves from the maximum extended state shown in FIG. 2 toward the retracted state shown in FIG.
[0027]
In addition, a back cover 20 is provided on the rear surface of the camera 10 to protect the photographic film when a cartridge (not shown) containing the photographic film is loaded in the camera 10. A back cover knob 19 for opening the back cover 20 is provided on the side surface of the camera 10.
[0028]
In addition, a film feeding chamber 21 and a film winding chamber 22 are provided inside the camera 10, and the film feeding chamber 21 is not shown by opening the back lid 20 with the back lid knob 20. Load the cartridge. Also, a DX code detection pin 23 is provided on the wall surface of the film feeding chamber 21, and a cartridge on which a DX code printed with information such as ISO sensitivity of a photographic film stored in the cartridge is printed. By loading the film feeding chamber 21 and closing the back cover 20, the DX code is automatically read by the DX code detection pin 23, and the camera 10 is set to the ISO sensitivity stored in the DX code. The
[0029]
In the OFF state, power is not supplied to the camera 10 from a battery (not shown). By turning the select dial 24 to switch to the program mode (P), power is supplied to the camera 10 and photography can be performed. It becomes a state.
[0030]
In the program mode (P), one of two programs to be described later is automatically selected according to the ISO sensitivity set by the DX code detection pin 23, and the above-described AE sensor is used in accordance with the selected program. In this mode, a combination of an aperture and a shutter speed is automatically set according to the measured LV value, and photography is performed based on the set aperture and shutter speed combination.
[0031]
FIG. 4 is an internal block diagram of the camera of this embodiment.
[0032]
4 shows a CPU 1 that controls the operation of the entire camera 10, a ROM 120 that stores a reference table represented by a program diagram to be described later, a zoom lens 11a composed of a fixed lens 111a and a moving lens 112a, and a moving lens 112a. A zoom motor 110 that moves the lens in the optical axis direction, a shutter mechanism 31 that also serves as an aperture mechanism, and a focus lens 32 are shown.
[0033]
The shutter mechanism 31 includes two shutter blades, a drive motor 313 that drives the shutter blades, and a plunger 316 that projects a pin 316a that restricts the aperture opening formed by the shutter blades.
[0034]
4 shows a driver 330 for controlling the driving of the zoom motor 11b, the driving motor 313, and the plunger 316, a code sensor 200 for reading the DX code of the cartridge loaded with the film 21a, a half-pressed state and a fully-pressed state. The shutter button 16 having the two-stage structure, the AE calculation circuit 150 that determines the exposure based on the subject brightness (LV value) detected by the AE sensor 151, and the operation on the shutter button 16 or the zoom operation lever 18 are transmitted to the CPU. An I / O controller 100 is also shown.
[0035]
In this camera 10, when zooming by the zoom operation lever is finished and the shutter button 16 is half-pressed while capturing the subject at the center of the angle of view, the focus lens 32 is moved on the optical axis and AE is performed. The exposure is determined by the arithmetic circuit 150.
[0036]
In the AE calculation circuit 150, first, an exposure value based on the luminance information (LV value) detected by the AE sensor 151 and the ISO sensitivity information of the film loaded in the camera that has already been detected by the code sensor 200. (Exposure Value: hereinafter referred to as EV value) is calculated.
[0037]
Further, the AE arithmetic circuit 150 refers to a table represented by a program diagram as shown in FIG. 7 corresponding to the current focal length of the zoom lens 11a based on the calculated exposure value (EV value). The shutter speed is determined. Thereafter, when the shutter button is fully pressed, the camera 10 takes a picture at the determined shutter speed, and the aperture is determined according to the shutter speed. In FIG. 4, illustrations of elements not related to the present invention such as an AF arithmetic circuit, a focusing mechanism, or a finder mechanism are omitted.
[0038]
FIG. 5 is a typical program line showing a program that defines a combination of an aperture value and a shutter speed according to an exposure value (EV value) of a camera equipped with a zoom lens (not shown) that is conventionally known. FIG.
[0039]
The horizontal axis of the program diagram shown in FIG. 5 indicates the shutter speed, the vertical axis indicates the aperture value, and the diagonal line indicates the EV value.
[0040]
Here, when comparing photographic films having different ISO sensitivities, the LV value and EV value when the shutter speed is the same and the aperture value is the same for one photographic film having the same ISO sensitivity and the other photographic film having the same ISO sensitivity. The relationship is that, in the case of a photographic film with ISO sensitivity 100, the LV value and the EV value are equal, but the amount of light taken into the photographic film necessary to obtain an appropriate amount of light is equal to the ISO sensitivity of the photographic film. Since it is inversely proportional to the height, if the sensitivity of the photographic film is increased by one step relative to the ISO sensitivity of 100, the EV value also increases by one step relative to the LV value. For example, when a photographic film having an ISO sensitivity of 100 is used, if the LV value is LV5, the EV value is EV5. However, the sensitivity of the ISO sensitivity 800 is three steps higher than that of the photographic film having an ISO sensitivity of 100. When a photographic film is used, when the LV value is LV5, the EV value is EV8.
[0041]
The program diagram shown in FIG. 5 shows an example of a wide focal length of a camera having a conventionally known zoom lens. In addition, this camera is also a camera provided with an aperture opening restriction mechanism, and as described in the section of the prior art, the aperture opening restriction is entered due to the problem of a decrease in peripheral light quantity when wide.
[0042]
Of the two programs shown in FIG. 5, the program indicated by the solid line is a program in which aperture restriction for the aperture is set, and the aperture value including the aperture restriction is F4.5.
[0043]
The program indicated by the other broken line is a program for canceling the aperture opening restriction, and the aperture value is F2.8. Of course, if the aperture restriction is removed, the decrease in the amount of peripheral light becomes conspicuous. Therefore, the aperture restriction is not removed when shooting in a bright place such as outdoors.
[0044]
On the other hand, when shooting in a dark place such as a night view, there are many scenes where the background is dark and the decrease in the amount of peripheral light is not noticeable. In photographing in such a place, it is desirable that the F value of the lens be small in order to prevent camera shake. For this reason, the camera of this embodiment enables bright shooting by removing the aperture restriction in shooting in a dark place such as a night view.
[0045]
FIG. 6 is a schematic diagram of a shutter mechanism that is provided in the camera of the present embodiment and that can regulate the opening.
[0046]
The shutter mechanism 31 that also serves as a diaphragm mechanism shown in FIG. 6 has two shutter blades 311 and 312, an arm member 315 that connects these two shutter blades, a plunger 316 that projects a pin 316 a, and a maximum aperture opening. And the upright pins 317 with which the shutter blades 312 come into contact.
[0047]
The arm member 315 rotates around a portion 315a to which the rotation shaft of the drive motor 313 is directly connected.
[0048]
The plunger 316 makes the operating range of one of the two shutter blades 312 smaller by projecting the pin 316a. FIG. 6A, in which the size of the aperture opening formed by the two shutter blades is regulated, shows a state in which the aperture opening 31c is completely closed. This is realized by the drive motor 313 rotating the rotating shaft counterclockwise.
[0049]
By rotating the rotating shaft of the drive motor 313 clockwise from the state shown in FIG. 6A, the aperture opening 31c is opened to the maximum as shown in FIG. 6B when the subject brightness is low. It becomes a state. This maximum opening (F value 2.8 in the camera of the present embodiment) corresponds to the first maximum opening referred to in the present invention.
[0050]
In the shutter mechanism 31, the maximum aperture opening is formed by moving the aperture opening to increase until one shutter blade 312 of the two shutter blades contacts the above-described standing pin.
[0051]
The shutter mechanism 31 opens and closes the shutter blades at the shutter speed determined by the AE arithmetic circuit. This shutter blade opening and closing operation is performed so that the shutter blades are opened and closed at the shutter speed determined by the AE arithmetic circuit. This is realized by the driver 33 controlling the drive motor 313 in accordance with an instruction from the CPU 1. FIG. 6C shows a view of the shutter mechanism 31 as viewed from the right side. In FIG. 6C, the pin 316a is moved to the upright pin 317 by the plunger 316. A state in which the shutter blade 312 is in contact with the abutting shutter blade 312 is shown. The details of the pin 316a that is projected by the plunger 316 at a position inside the standing pin 317 (left side in FIG. 6) will be described later.
[0052]
FIG. 7 is a program diagram that defines combinations of aperture values and shutter speeds according to exposure values (EV values) in the camera of the present embodiment.
[0053]
The program diagram shown in FIG. 7 corresponds to the set ISO sensitivity when the zoom lens 11a is set to a short focal length by pressing one operation portion 18b of the zoom operation lever 18 (see FIG. 3). The horizontal axis of the program diagram indicates the shutter speed, the vertical axis indicates the aperture value of the zoom lens 11a, and the diagonal line indicates the EV value.
[0054]
A program indicated by a solid line or a broken line in FIG. 7 indicates the control contents in each film sensitivity in the range from ISO50 to ISO1600.
[0055]
Of the programs indicated by the solid line or the broken line in FIG. 7, the program indicated by the solid line is a program in the case of ISO 1600. Until EV 9.5 (LV5.5), the aperture opening restriction indicated by the solid line in FIG. Performs the same control as the set program control. LV5.5 is a darker scene than the room and becomes a night scene.
[0056]
As shown in FIG. 6C, the opening restriction is such that the plunger 316 protrudes the pin 316a, and if the pin 316a does not protrude, the shutter blade 312 moves to the position of the standing pin 317 described above. This is done by restricting the range to the inside of the pin 316a. When the pin 316a is protruded, the maximum aperture of the diaphragm aperture becomes a size slightly narrower than the size shown in FIG.
[0057]
In the camera of the present embodiment, when the focal length of the zoom lens 11a is shortened, the CPU 1 instructs the driver to project the pin 316a by the plunger 316 in order to restrict the aperture opening, and the zoom lens. The shutter speed is determined by referring to a table corresponding to the current focal length 11a and aperture regulation of 11a.
[0058]
Further, in the camera according to the present embodiment, when it is assumed that the object scene has gradually become dark, even when the focal length of the zoom lens is short, when the measured object field brightness is LV5.5 or less, the camera is projected. When the pin 316a has been retracted, the aperture restriction of the aperture is released, and after the aperture value has moved from F4.5 to F2.8, exposure control is performed by reducing the shutter speed as it is. Note that the maximum opening (F value 4.5 in the camera of the present embodiment) among the openings that can be formed by opening restriction corresponds to the second maximum opening of the present invention.
[0059]
For films from ISO 800 to ISO 50 other than ISO 1600, as shown by the broken lines in FIG. 7, the opening restriction is canceled by following a diagram shifted to the slower shutter speed by 1 EV each.
[0060]
As described above, when shooting in a dark place, the aperture restriction is canceled and the F value is reduced to achieve bright depiction shooting. In the camera 10 of the present embodiment, when the film sensitivity is ISO 1600, the exposure amount when the shutter speed is 1/30 seconds is EV8. Therefore, the brightness that can be photographed when the shutter speed is 1/30 seconds or less is LV4. The brightness that can be taken at a shutter speed of 1/30 sec or less with a conventional camera in which the aperture is regulated regardless of the field luminance shown in FIG. 5 is EV9.5 in the case of ISO 1600, that is, LV5.5. Therefore, according to the camera 10 of the present embodiment, the range in which a bright photograph can be taken by about 1.5 stops is increased as compared with the conventional camera. Here, ISO 1600 is taken as an example, but the same applies to other sensitivities. To prevent camera shake, it is possible to expand the shooting range in dark places such as when limiting the shutter speed to 1/30 seconds or less, and it is possible to take a beautiful night view without using a tripod Become.
[0061]
In this embodiment, an example of a camera equipped with a zoom lens has been described. However, the camera of the present invention is not limited to this. For example, the camera can be switched to either a wide-angle magnification or a telephoto magnification to take a picture. The present invention can also be applied to a camera having a photographing lens whose focal length can be switched to either the wide-angle side or the telephoto side, such as a camera having a photographing lens that can be performed.
[0062]
Further, in the present embodiment, the example of a camera equipped with a zoom lens has been described. However, the camera of the present invention may include a single focus lens that does not have a zoom function.
[0063]
Furthermore, in the present embodiment, the case where photographing is performed on a photographic film has been described as an example. However, the present invention is not limited thereto, and the photographing may be performed on a solid-state imaging device.
[0064]
【The invention's effect】
As described above, according to the present invention, there is provided a camera capable of shooting a bright depiction in shooting in a dark place where reduction in the amount of peripheral light is not a problem.
[Brief description of the drawings]
FIG. 1 shows a camera equipped with a zoom lens that is an example of a variable focal length photographic lens according to an embodiment of the present invention, and a zoom lens barrel that supports the zoom lens is housed in the camera body. It is a perspective view which shows a state.
2 is a perspective view showing a maximum extended state in which the zoom lens barrel is extended to the maximum extent in the camera shown in FIG. 1; FIG.
FIG. 3 is a perspective view of the camera shown in FIGS.
FIG. 4 is an internal block diagram of the camera of the present embodiment.
FIG. 5 is a typical program diagram showing a program that defines a combination of an aperture value and a shutter speed according to an EV value of a camera having a zoom lens (not shown) that is conventionally known.
FIG. 6 is a schematic view of a shutter mechanism that is provided in the camera of the present embodiment and that can regulate the opening.
FIG. 7 is a program diagram that defines combinations of aperture values and shutter speeds according to EV values in the camera of the present embodiment.
[Explanation of symbols]
1 CPU
DESCRIPTION OF SYMBOLS 10 Camera 100 I / O controller 11 Zoom lens barrel 11a Zoom lens 11b Zoom motor 111a Fixed lens 112a Moving lens 12 Flash light emission window 13 Viewfinder objective window 14a AF light projection window 14b AF light reception window 15 AE light reception window 150 AE arithmetic circuit 151 AE Sensor 16 Shutter button 17 Viewfinder eyepiece window 18 Zoom operation levers 18a and 18b Operation unit 19 Back cover knob 20 Back cover 21 Film feeding chamber 21a Film 22 Film winding chamber 23 DX code detection pin 24 Select dial 120 ROM
200 Code sensor 31 Diaphragm mechanism 311, 312 Diaphragm blade 31c Aperture opening 313 Drive motor 315 Arm member 315a Part 316 Plunger 316a Shaft 32 Focus lens 330 Driver

Claims (3)

When the photographic optical system with variable focal length and the photographic optical system is set to a focal length less than or equal to a predetermined focal length, the maximum aperture is set to a predetermined long focal length. A camera that is controlled by a second maximum aperture that is narrower than the first maximum aperture, and that performs imaging by capturing subject light incident through the imaging optical system and the aperture,
A metering unit for measuring the field luminance;
When the field luminance measured by the photometry unit is a field luminance equal to or lower than a predetermined field luminance, the aperture restriction of the diaphragm is released, and the aperture is measured by the metering unit. A camera comprising: an aperture restriction canceling unit that sets an aperture between the first maximum aperture including the first maximum aperture and the second maximum aperture in accordance with field brightness.   The camera according to claim 1, wherein the aperture restriction canceling unit sets the aperture to the first maximum aperture when the aperture restriction of the aperture is cancelled. 2. A camera according to claim 1, wherein the camera is loaded with a photographic photosensitive member and takes a picture on the loaded photographic photosensitive member .

Images