JP2000267161A - Stroboscopic device and film unit with lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a print with an appropriate density ratio (principal subject/ background) in any photographing environment. SOLUTION: This stroboscopic device 10 is constituted of a photometry part 22 measuring subject luminance on an exposure image plane 32, an emitted light quantity control part 24 adjusting the emitted light quantity of a stroboscope based on a photometric value obtained by the photometry by the photometry part 22, and a strobe light emitting part 9. The photometric value is obtained by performing the average photometry of an entire subject within the image plane 32 including the principal subject 33 and the background 34. The emitted light quantity of the stroboscope is adjusted so that it may get larger and larger as the subject luminance gets higher and higher. At the time of photographing, the determination light emission is performed based on the decided emitted light quantity of the stroboscope. Thus, the density ratio of the principal subject 33 at which strobe light arrives to the background 34 at which the strobe light does not arrive gets proper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a strobe device having a function of adjusting a strobe light emission amount, and a lens-equipped film unit incorporating the strobe device.

[0002]

2. Description of the Related Art Cameras with a built-in strobe device have become widespread so that images can be taken even in dark places such as indoors or at night. The strobe device irradiates a subject with strobe light emitted from a discharge tube, thereby compensating for a lack of subject brightness. Some of such strobe devices have a fixed light emission amount for strobe light emission with a fixed light emission amount, and an automatic light control function for automatically controlling the amount of strobe light to be applied to a subject (automatic strobe light). ). Since these strobe devices are relatively inexpensive, they are used in inexpensive compact cameras with a fixed shutter speed, and in film units with lenses in which a photographic film is loaded in advance and a simple exposure mechanism is provided.

In particular, a film unit with a lens is strongly limited in terms of cost, has a built-in strobe with a fixed light emission amount at the lowest cost, and has been developed only with a fixed exposure condition such as an aperture as well as a shutter speed. Have been. This has enabled a thorough cost reduction.

On the other hand, an auto strobe has an automatic light control function. As a light control method, the brightness of an object irradiated with the strobe light is measured, and a time integration value of the measured value is calculated. A system in which the emission of strobe light is stopped as soon as a predetermined level is reached is mainly employed. In this method, the light receiving element measures the brightness of the subject including the amount of strobe light irradiation, and when the level of the measured light amount reaches an appropriate exposure value set in advance according to the film sensitivity, the strobe light emission is performed. Is stopped. Thus, it is possible to control the amount of light so that the subject existing in the range where the strobe light reaches can always be properly exposed.

[0005]

However, in the case of a strobe or an auto strobe having a fixed light emission amount, there is a problem that the fluctuation of the density ratio between the main subject and the background becomes large due to the difference in the photographing environment such as the subject distance. . Hereinafter, this will be described using two specific examples.

First, as a first specific example, when the background luminance is E
Consider that a person standing at a place where the background is at infinity is a main subject and the appropriate exposure determined by the film sensitivity is taken by an EV7 camera. In this case, the person is backlit and has only a brightness of EV5 or less.

In such a situation, when photographing is performed using a strobe having a fixed light emission amount, the density ratio of the main subject / background varies depending on the distance of the person. If the distance of the person is 3
m, when the strobe light amount is set to an appropriate exposure (EV7), a backlit print is obtained at a distance of 3 m or more, and when about 2 m, the density ratio of the main subject / background is an appropriate print. Sometimes people overexposure,
The background is a black print.

[0008] On the other hand, in the same situation, when the photographing is performed using an auto strobe, if the photographing is performed within a distance of 3 m from the person, the main subject is raised to EV7, and all the images are properly exposed. In the above, the background is EV8, and the exposure is over, resulting in a print in which backlight has not been corrected. Further, depending on the type of the auto strobe, the amount of light emission is reduced due to the influence of the background brightness, and the main subject may be underexposed (EV7 or less). Further, when an object is present on the camera side of the main subject, the amount of strobe light emission is further reduced due to the influence of the reflection, and the main subject becomes underexposed.

Next, as a second specific example, when the background luminance is E
Consider that a person standing at a place where the background is at infinity is a main subject and the appropriate exposure determined by the film sensitivity is taken by an EV7 camera. It is also assumed that the person is illuminated by a spotlight and has a brightness of EV8.

In such a situation, when photographing is performed using a strobe having a fixed light emission amount, as in the first embodiment, the density ratio of the main subject / background varies depending on the distance of the person. If the strobe light amount is set such that the proper exposure (EV7) is obtained when the distance of the person is 3 m, the whiteout of the person occurs and the background becomes completely dark when photographing within 3 m. On the other hand, in the case of shooting using an auto strobe, if the shooting is within 3 m, as in the case of a strobe with a fixed light emission amount, the person will be overexposed and the background will be printed completely dark.

As described above, when a strobe having a fixed light emission amount is used, the density ratio (main subject / background) is likely to vary depending on the distance between the main subject. It fluctuates easily under the influence of the front and rear luminance.

The present invention has been made to solve such a problem, and has as its object to produce a print having an appropriate density ratio (main subject / background) in any photographing environment. .

[0013]

In order to achieve the above object, a flash device according to the present invention comprises a photometric device for measuring the luminance of a subject, and a light emission amount of the strobe based on a photometric value measured by the photometric device. Light emitting amount adjusting means for adjusting,
The light emission amount adjusting means adjusts the light emission amount of the strobe so as to increase as the subject luminance increases.

Further, a film unit with a lens according to the present invention is characterized in that the above-mentioned strobe device is built in. Further, based on the photometric value measured by the photometric means, the aperture of the aperture constituting a part of the exposure mechanism is set to at least 2
It is characterized by comprising aperture switching means for switching to stages.

[0015]

FIG. 2 shows the appearance of a camera embodying a strobe device of the present invention. The camera 2 is provided with a lens barrel 3 on the front surface of the body. When a main switch (not shown) of the camera 2 is turned on, the camera 2 is extended from the retracted position to the illustrated photographing position. The lens barrel 3 has a pan-focus shooting lens 4
Is incorporated. A program shutter is provided behind the taking lens 4, and performs appropriate exposure control according to the amount of light of the subject.

A photometric window 14 is provided below the photographic lens 4 so as to face the subject, and a light receiving element is incorporated therein. A finder objective window 5 is provided above the lens barrel 3, and a strobe light emitting unit 9 is provided beside the finder objective window 5.

A shutter button 11 is provided on the upper surface of the body. When the shutter button 11 is half-pressed, the brightness of the entire subject is measured by the photometric window 14, and the amount of strobe light is adjusted based on the photometric value. Then, when the shutter button 11 is fully pressed, the flash fires,
The program shutter is opened and closed.

On the upper surface of the body, in addition to the shutter button 11, a liquid crystal display panel 7 and a changeover switch 8 for designating a print range for each frame are provided. When the main switch is turned on, the liquid crystal display panel 7 is turned on to display the number of film shots, the print range specified for each shot frame, and the like.

A lock member 16 is provided on the side surface of the body, and regulates opening and closing of a bottom cover for taking out a photo film provided on the bottom surface. The photo film is loaded by releasing the lock member 16 and opening and closing the bottom cover. The photo film uses an IX240 type cartridge. Therefore, when the photo film is loaded and the main switch is turned on, the film sensitivity recorded on the photo film is automatically set.

As shown in FIG. 1, a strobe device 10 incorporated in a camera 2 includes a photometer 22 and a light emission controller 2.
4, an electronic flash unit 9 for controlling the amount of electronic flash. The strobe device 10 is of a constant light emission type, and charging is started when a main switch is turned on, and charging is repeated every photographing. Of course, it is not necessary to use a constant light emission type.

The photometer 22 is linked to the exposure controller 26. The exposure control section 26 controls the shutter drive section 39 to make the aperture value appropriate. This control is performed based on the photometric value and the film sensitivity of the photographic film 27. As described above, the sensitivity of the photo film 27 is read at the time of loading, and the exposure control unit 26 and the light emission amount control unit 24 are read.
Entered as

The photometric section 22 includes a light receiving element 29 and a photometric circuit 31. As the light receiving element 29, for example, Cds (photoconductive element) is used, and is incorporated in the depth of the photometry window 14. The light metering circuit 31 sends the level signal of the light amount received by the light receiving element 29 to the light emission amount control unit 24 and the exposure control unit 26.
And send to.

The light receiving element 29 performs an average photometry on the entire subject within the exposure screen 32. Thereby, for example, the exposure screen 3
The exposure screen 32 includes not only the subject brightness of the main subject 33 (shown by a person in FIG. 1) but also the subject brightness of a background 34 (shown by a mountain in FIG. 1) having a distance difference around the main subject 33.
The brightness of the entire subject to be exposed is measured.

The light emission amount control unit 24 adjusts the light emission amount based on the light measurement value input from the light measurement unit 22, and performs control so that the strobe light emission unit 9 emits a fixed amount of light at the light emission amount determined by the adjustment. . This strobe light emission amount is adjusted so as to increase as the luminance of the entire front subject increases.

The relationship between the subject luminance and the amount of flash light emission is shown, for example, in the graph of FIG. In the graph of FIG. 3, the horizontal axis indicates the photometric value LV of the subject luminance measured by the photometric unit 22, and the vertical axis indicates the amount of strobe light emission by the guide number Gno. In this example, the minimum strobe light emission amount is a guide number “2”, and the maximum strobe light emission amount is a guide number “10”. In the meantime, the guide number Gno is proportionally increased as the photometric value LV increases. These values are variously selected depending on the film sensitivity of the photographic film 27 and the like.

As described above, if the amount of strobe light is increased while the brightness of the entire subject exposed on the exposure screen 32 (FIG. 1) is high, the strobe light reaches the main subject 33 that is close to the camera 2. Therefore, its brightness increases.
On the other hand, since the distance is long, the strobe light does not reach the background 34, and its luminance does not change. For this reason, the exposure value of the background 34 having a high luminance and the main subject 3 having a relatively low luminance
A balance with an exposure value of 3 is achieved. This prevents the main subject 33 from sinking into the brightness of the background 34.

When the brightness of the entire subject is low, the main subject 33 is illuminated with a small amount of strobe light, so that an increase in the brightness of the main subject 33 is suppressed. This allows
The exposure value of the background 34 having low luminance and the exposure value of the main subject 33 having relatively high luminance are balanced, so that the main subject 33 does not float in the dark background 34.

The exposure control unit 26 controls the program shutter based on the photometric value input from the photometric unit 22.
In this program shutter, the shutter speed is fixed, and only the aperture is adjusted according to the photometric value. The exposure controller 26 drives the program shutter via the shutter driver 39 with the adjusted aperture.

As described above, the photometric value and the amount of strobe light emission have a one-to-one correspondence based on a predetermined relationship. For this reason, in the exposure control, the exposure value of the main subject 33 based on the flash emission amount corresponding to the photometric value
The exposure is performed so as to match an appropriate exposure value according to the film sensitivity. Thus, the image of the main subject 33 formed on the photographic film 27 can be kept within an appropriate exposure value even if the strobe light amount is determined in proportion to the luminance of the entire subject.

The operation of the above configuration will be described with reference to the flowchart shown in FIG. When the photo film is loaded and the main switch is turned on, the liquid crystal display panel 7 is turned on, and the number of photographed films, the film sensitivity, and the like are displayed. At this time, the film sensitivity is input to the light emission amount control unit 24 and the exposure control unit 26.

The exposure screen 32 is defined by framing the photographic lens 4 toward the subject. When the shutter button 11 is half-pressed, the photometry unit 22 operates, and the exposure screen 3
The luminance of the entire subject contained in the area 2 is measured. This photometric value is transmitted to the light emission amount control unit 24 and the exposure control unit 26.

The light emission amount control unit 24 determines a flash light emission amount (guide number) based on the photometric value in accordance with the correspondence shown in the graph of FIG. When the luminance of the entire subject is high, the amount of strobe light applied to the main subject 33 is increased, and an exposure balance with the background 34 is achieved. On the other hand, when the luminance of the entire subject is low, the amount of strobe light applied to the main subject 33 is reduced, and the exposure balance with the background 34 is maintained.

On the other hand, the exposure controller 26 determines the aperture based on the photometric value. As a result, the exposure value of the main subject 33 including the determined strobe light emission amount is adjusted to a range allowed by the photographic film (color negative film).

When the shutter button 11 is fully pressed, the program shutter opens and closes at the determined aperture and a fixed shutter speed. At the same time, the flash emission unit 9
Emits quantitative light at the determined strobe light emission amount. The subject light including the reflected light of the strobe light applied to the main subject 33 enters the photographic lens 4 and forms an image on a photographic film.

As described above, the amount of strobe light is adjusted in proportion to the luminance of the subject, and the main subject 33 and the background 34 are recorded with an appropriate density balance. A print of the ratio (main subject / background) can be obtained.

In the strobe device of the above embodiment, the guide number is determined based on the photometric value, and the fixed number is used for the guide number. However, other than this, for example, an auto strobe may be used. In this case, the target light emission amount is determined based on the light measurement value, and the light emission is stopped when the integrated value of the measured light amounts of the object brightness including the irradiated strobe light reaches the determined target light emission amount. The relationship between the photometric value and the target light emission amount in this case is, for example, as shown in FIG. Here, "1.0" indicates an appropriate exposure value of the film. In the case of using the auto strobe, the photometry unit and the light emission amount control unit of the above-described embodiment and the like cannot be used as they are, and an auto strobe is required.

The camera used in the above embodiment is IX
Although a 240 type cartridge is used, a 135 type cartridge may of course be used. In this case, a mechanism for setting the film sensitivity of the loaded photographic film is required. Although the above embodiment has been described as being incorporated in a compact camera, the present invention may be applied to a lens-equipped film unit, which is a simple camera in which a photographic film is pre-loaded as shown in the second embodiment.

FIGS. 6 and 7 schematically show the appearance and internal structure of a film unit 41 with a lens according to a second embodiment.
The film unit with lens 41 is composed of a unit main body composed of a main body base 44 to which the exposure unit 42 and the strobe device 43 are assembled and a front cover 46 and a rear cover 47 put on the front and rear thereof, The photo film 51 is drawn out into a roll form.

Cartridge 49 and photographic film 51
Is a cartridge storage chamber 44 formed in the main body base 44.
a and the film storage chamber 44b are preliminarily incorporated into the film unit with lens at the time of manufacture. The film sensitivity of the photo film 51 is, for example, ISO 1600.

The front cover 46 has a photographing window 5 on its front.
2, a finder objective window 53, a strobe light emission window 54, and a photometry window 56 are formed, and a strobe switch 57 is provided. On the upper surface, a shutter button 58 and a film counter window 59 are formed. A finder eyepiece window 61 is formed on the rear cover 47, a charging completion confirmation window 62 is formed on the upper surface, and bottom lids 47a and 47b that integrally cover the bottom openings of the cartridge storage chamber 44a and the film storage chamber 44b are formed integrally. ing. The bottom cover 47a is opened when taking out the cartridge 49 in which the photographed film has been taken.

A hoisting knob 63 is provided above the cartridge storage chamber 44 a, and a hoisting shaft integrally formed on the lower surface thereof engages with the spool of the cartridge 49. By rotating the winding knob 63 for each shooting,
The photographed photo film 51 is wound into the cartridge 49 one frame at a time. The shutter mechanism incorporated in the exposure unit 42 is charged for the next photographing in conjunction with the winding of one frame of the film, and when the feeding of one frame of the film is completed, the winding lever 63 is activated by the lock lever incorporated in the exposure unit 42. Is locked.

An exposure frame 44c is formed in the main body base 44. The frame 44c limits the exposure range for one frame on the front surface of the photographic film 51 sent to the photographing position.
In front of the exposure frame 44c, a dark box base 44 protruding in the shape of a square tube is provided.
d are integrally formed, and the exposure unit 42
Is assembled to form a dark box in cooperation with the dark box section 42a on the exposure unit 42 side.

The exposure unit 42 includes a photographic lens 66, a shutter mechanism including shutter blades (see 83 in FIG. 8), a shutter charging mechanism, a winding stop mechanism, a film counter plate, and the like assembled on the basis of the dark box section 42a. ,
Further, it holds an objective and an eyepiece constituting a finder optical system.

The taking lens 66 has, for example, a focal length of 2
A 4 mm lens is incorporated. The photographing window 52 located in front of the photographing lens 66 functions as a large aperture opening for setting the F-number to “5.6”. And
An aperture switching plate 67 is provided between the photographing lens 66 and the photographing window 52. This aperture switching plate 67
Is formed at one end thereof with a small aperture opening 68 for setting the F-number to "22", and the small aperture opening 68 is provided so as to be freely inserted into and removed from the photographing optical path.

As shown in FIG. 8, the aperture switching plate 67 is provided with a bearing hole 69. This bearing hole 69
The shaft 47a provided on the front cover 46 is inserted into the, and the aperture switching plate 67 is rotatably supported. The aperture switching plate 67 is urged by a spring 71 in a counterclockwise direction as viewed from the front, and a position retracted from the front of the photographing lens 66 indicated by a solid line in FIG.

An iron core 72 is provided at one end of the bearing hole 69 opposite to the small stop opening 68. The iron core 72 is attracted by an electromagnet 73 provided on the front surface of the strobe device 43, whereby the aperture switching plate 67 is rotated. The electromagnet 73 is electrically connected to the circuit board 74 of the strobe device 43, and is turned on when a predetermined current flows. When the electromagnet 73 is turned on,
The iron core 72 is attracted against the bias of the spring 71, and the aperture switching plate 67 is rotated.

The strobe device 43 provided with the electromagnet 73 includes a circuit board 74 on which a circuit pattern is printed.
Further, a strobe light emitting section 79 including a strobe discharge tube, a reflector, and the like, and a battery 81 for a power supply (see FIG. 7) are held. The circuit board 74 includes a main capacitor 7
6, synchro switch 77, booster coil, light receiving element 78
Various circuits are configured by attaching components such as the above.

The strobe light emitting section 79 and the light receiving lens 84 provided on the front surface of the light receiving element 78 are exposed to the outside through the strobe light emitting window 54 and the photometric window 56 on the front surface of the front cover 46, respectively.

The charging of the strobe device 43 is performed by sliding the strobe switch 57. When the switch piece 81 attached to the front surface of the circuit board 74 is pressed by the sliding of the strobe switch 57, conduction is conducted between the pair of contacts 82 to start charging.
When the charging of the main capacitor 76 is completed, for example,
The LED provided on the circuit board 74 lights up. This light is confirmed by the photographer through the charging completion confirmation window 62.

The synchro switch 77 includes the shutter blade 8
3 for transmitting a trigger signal in conjunction with the opening and closing of the shutter 3 when the shutter blade 83 is fully opened.
Is turned on, and strobe light emission is performed.

On the circuit board 74, in addition to a charging circuit for boosting the voltage of the battery 81 to charge the main capacitor 76, as shown in FIG. 9, a photometry circuit 87, a light emission amount control circuit 88,
An aperture switching circuit 92 is provided. These circuits control the aperture switching plate 67 and adjust the amount of strobe light emission.

The photometric circuit 87 transmits a signal corresponding to the amount of light received by the light receiving element 78 to the light emission amount control circuit 88 and the aperture switching circuit 92. The light receiving element 78 is made of, for example, Cds of a photoconductive element, and performs average photometry of the entire subject facing the front surface of the film unit 41 with a lens.

The light emission amount control circuit 88 adjusts the amount of strobe light emission based on the photometry value received from the photometry circuit 87.
Upon receiving a trigger signal from the synchro switch 77, the strobe light emitting section 79 performs quantitative light emission with the adjusted light emission amount.

This strobe light emission amount (guide number)
Is adjusted, for example, based on the correspondence with the photometric value LV as shown in the graph of FIG. In this example, the minimum strobe light emission amount is a guide number “2”, and the maximum strobe light emission amount is “10”. During this period, the strobe emission amount is set so as to increase stepwise as the photometric value LV increases.

In this embodiment, the minimum value to the maximum value are 4
Although it is divided into stages, it is not limited to four stages and may be four stages or less. Further, the values of the amount of strobe light and the photometric value are not limited to the values shown in the figure. For example, the relationship between the amount of strobe light and the photometric value is set in consideration of the sensitivity of the photo film 51 loaded in advance.

By adjusting the amount of strobe light as described above,
When the background 89 is bright, strobe light having a larger light emission amount is irradiated. Therefore, the subject brightness of the main subject 91 to which the strobe light reaches increases according to the background 89.
For this reason, the main subject 91 does not sink into the brightness of the background 89. Further, when the background 89 is dark, the strobe light having a smaller light emission amount is irradiated, and an increase in the subject brightness of the main subject 91 to which the strobe light reaches can be suppressed. For this reason, the main subject 91 does not rise in a dark background.

On the other hand, the photometric value measured by the photometric circuit 87 is sent to the aperture switching circuit 92. When the photometric value is equal to or greater than LV “13”, the aperture switching circuit 92 supplies a predetermined current to turn on the electromagnet 73. As a result, the electromagnet 73 rotates the aperture switching plate 67, and the small aperture opening 68 is inserted into the photographing optical path to perform aperture switching.

By switching the aperture, the exposure value of the subject light including the reflected light of the strobe light can be adjusted to an appropriate exposure value corresponding to the sensitivity of the photographic film 51. Further, in the film unit with lens 41, since the photographic film 51 is loaded in advance, the film sensitivity can be assumed. Therefore, the size (F value) of the aperture opening formed in the aperture switching plate 67 and the amount of strobe light emission can be set in advance in accordance with the loaded film sensitivity.

Next, the operation of the above configuration will be described with reference to the flowchart of FIG. When performing flash photography, the main switch 76 is started by sliding the flash switch 57. Check that charging is complete,
The winding knob 63 is rotated. Thereby, the one-frame feeding of the photo film 51 is completed and the shutter is charged. After framing is completed, shutter button 5
Press 8. When the shutter blade 83 opens and closes and reaches the fully open position, the sync switch 77 is turned on and a trigger signal is transmitted.

On the other hand, the light receiving element 78 measures the brightness of the entire subject in front of the lens-fitted film unit 41. The light emission amount control circuit 88 determines the amount of strobe light emission based on the photometric value. The strobe device 43 that has received the trigger signal emits a fixed amount of light at the determined amount of strobe light emission and irradiates the object with strobe light.

At this time, if the photometric value LV is equal to or more than "13", the aperture switching circuit 92 is operated to rotate the aperture switching plate 67, and to bring the small aperture 6 into the photographing optical path.
Insert 8. On the other hand, when the photometric value LV is equal to or less than “13”, the aperture switching circuit 92 does not operate, and the aperture remains at the imaging window 52. With these, Photo Film 5
An appropriate exposure value corresponding to the film sensitivity of 1 can be obtained.

The amount of the subject light including the reflected flash light is controlled by switching the aperture, and the controlled subject light enters the dark box by opening and closing the shutter blades 83 to form an image on the photographic film 51.

In the above-described embodiment, a description has been given of a case where the photographer can arbitrarily select whether or not to use a flash. However, a strobe device that constantly emits light may be used. Also, the switching of the aperture has been described using the rotating aperture switching plate, but the aperture switching plate may be configured to slide and switch.

The sensitivity of the loaded photographic film was set to ISO1.
600, but is not limited to ISO1600.
For example, ISO400 or ISO1600 or more may be used. As described above, in the film unit with a lens, the aperture and the amount of strobe light emission are set based on this film sensitivity. Even with the same film sensitivity, it is possible to change the combination of the set values of the aperture and the amount of strobe light emission.

Further, an example has been described in which the aperture is switched in two stages of a small aperture opening and a large aperture opening. However, the aperture may be switched in two or more stages. According to this, finer exposure control can be performed based on the photometric value of the subject luminance.

Although the exposure control is performed by switching the aperture, the photographic film may be exposed without performing the exposure control at the time of photographing, and the exposure control may be performed by digital image processing at the time of print processing. . This digital image processing is performed by, for example, correcting the gradation in such a manner that, in the case of underexposure, the linear portion extends to the foot of the characteristic curve of the photographic film. According to this, since the aperture switching means becomes unnecessary, the structure of the film unit with lens can be made simpler.

[0067]

As described in detail above, the strobe device according to the present invention and the film unit with a lens incorporating the strobe device adjust the light emission amount so that the light emission amount of the strobe increases as the brightness of the subject increases. Since the means is provided, a print having an appropriate density ratio (main subject / background) can be created in any photographing environment.

Further, as shown in this embodiment, if an average photometer is used as the photometer, it is possible to produce a print having the above-mentioned density ratio with a simple configuration and at low cost. Therefore, the present invention can be applied to an inexpensive compact camera and a film unit with a lens.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing control of a flash device.

FIG. 2 is an external perspective view of a camera having a built-in flash device.

FIG. 3 is a graph showing a relationship between a guide number of a strobe device and a photometric value.

FIG. 4 is a flowchart showing a processing procedure at the time of photographing by a camera.

FIG. 5 is a graph showing a relationship between a target light emission amount of a strobe device and a photometric value.

FIG. 6 is an external perspective view of a film unit with a lens.

FIG. 7 is an exploded perspective view of the film unit with a lens.

FIG. 8 is a perspective view showing a main part of an exposure unit and a strobe device.

FIG. 9 is a configuration diagram showing control of a film unit with a lens.

FIG. 10 is a graph showing a relationship between a guide number of a strobe device provided in a film unit with a lens and a photometric value.

FIG. 11 is a flowchart showing a processing procedure when shooting a film unit with a lens.

[Explanation of symbols]

 2 Camera 9, 79 Strobe light emitting part 22 Light metering part 24 Light emission amount control part 26 Exposure control part 29, 78 Light receiving element 31, 87 Light measuring circuit 32, 86 Exposure screen 33, 91 Main subject 34, 89 Background 41 Film unit with lens 43 Strobe device 67 Aperture switching plate 88 Light emission amount control circuit 92 Aperture switching circuit

Claims (3)

[Claims] 1. An image forming apparatus comprising: a photometer for measuring the brightness of a subject; and a flash adjuster for adjusting a flash quantity of the strobe based on a photometric value measured by the photometer. A strobe device characterized in that the strobe light emission amount is adjusted to increase as the image height increases. 2. An unexposed photographic film is loaded in advance,
2. A film unit with a lens, comprising a built-in exposure mechanism for exposing the photographic film and a flash device according to claim 1. 3. An aperture switching means for switching an aperture diameter of an aperture constituting a part of the exposure mechanism in at least two stages based on a photometric value measured by the photometric means. 2. The film unit with a lens according to 2.