JP2000221569A - Film unit with lens provided with built-in stroboscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make preventable a background from being photographed darkly by making the shutter speed at the time of photographing with strobe light and the guide number of a stroboscopic device satisfy a specified condition. SOLUTION: A stroboscopic switch lever is fixed onto the right arm 11c of a diaphragm plate 11, and guide pins 12 erected from a fixed substance such as a unit main body are fit in two slots 11d bored in the lateral direction of the plate 11. Therefore, the plate 11 slides in a right-and-left direction by the sliding operation of the stroboscopic switch lever. When it is assumed that the shutter speed at the time of photographing with strobe light is SS and the guide number in the case of ISO 100 of the stroboscopic device is Gno, they satisfy a conditional expression GNo2/SS<8000. Desirably, the expression is set to GNo2/SS<6500, more desirably, it is set to GNo2/SS<5000. In the case of exceeding the upper limit of the expression, the difference between exposure by strobe light and the exposure of the background by external light gets too large.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens-equipped film unit having a built-in flash.

[0002]

2. Description of the Related Art Conventionally, since a film unit with a lens has been designed to be simple and inexpensive, it has no mechanism for adjusting the exposure, and the aperture is only the aperture of the taking lens. , Shutter speed is 1/12
It is about 5 speeds. The taking lens is composed of one or two plastic lenses, and the F value of the open aperture is 1
It is as dark as 0. Therefore, if an ISO 100 film is used, the shooting is limited to daylight sunny weather. Therefore, an ISO 400 film is mounted so that shooting can be performed with a little lower brightness.

For example, when the shutter speed is set to 1/125,
If the aperture is 11 in F number, the exposure amount in ISO 100 is EV14. Accordingly, when an ISO400 film is used, the EV value becomes 12, and by relying on the latitude of the film or the photographic paper, it becomes possible to take a picture from a clear day to a dim morning and evening.

However, even in this case, it is impossible to take a picture indoors or at night. Therefore, there is a film unit with a lens which has a built-in strobe to enable low-brightness photography. But,
In a film unit with a lens, it is difficult to incorporate a large-capacity strobe because it hinders downsizing and increases the cost, so that the guide number in ISO 100 is usually about 10. For this reason, ISO400
When the F-number is set to 11 and the shooting distance of the appropriate exposure is relatively short, 1.8 m, it is assumed that the shortage of the exposure amount up to EV1.5 can be compensated by the latitude of the film or the like. The limit is about 3.0 m.

[0005] In order to extend the photographing distance when using a strobe, a film unit with a built-in strobe lens loaded with an ISO800 film is commercially available. As a result, under the same conditions as above, the photographing distance for proper exposure is 2.
5 m, and if the exposure amount of EV1.5 is allowed to be insufficient, the shooting distance is extended to 4.3 m.

[0006]

In flash photography, since the photographing distance for proper exposure is one point, if a main subject such as a person is set at that distance, a subject at a shorter distance than that subject will be overexposed. However, the background subject at a long distance becomes underexposed. Since the film loaded in the film unit with the lens is a negative film, the latitude is wide in the direction of overexposure, and this does not cause much problem for a subject at a short distance. On the other hand, the background subject is not so far away when photographing in a small room such as at home, and the strobe light bounces on various objects to irradiate the background, so that the exposure is not less than the calculated exposure. In addition, since there is illumination other than the strobe light in a room such as a home, the underexposure of the background is also reduced by this.

[0007] However, flash photography is not limited to indoors such as at home, but is also performed in a large room such as a hotel lobby or outdoors with little illumination. In this case, if a main subject such as a person is placed at an appropriate shooting distance, the main subject will be properly exposed. However, if the background distance is several tens of meters, no strobe light reaches the background at all.

Conventional film units with lenses include I
Some have a built-in SO800 film.
The value is 10.3, the shutter speed is 1/110, and the guide number of the strobe is 11.6 in ISO100. Therefore, shooting with external light has proper exposure at EV10.5, and shooting with strobe light has proper exposure at a distance of 3.2 m.

2. The lens-equipped film unit is used in a large room such as a hotel lobby or outdoors with little illumination.
If the main subject is placed at a distance of 2 m and flash photography is performed, the main subject will be properly exposed. In addition, distant backgrounds where strobe light does not reach are exposed only by external light,
The latitude of the film is 1.5 EV at the underexposure side.
Therefore, if the distant background has the brightness of the EV9 rank, the background can be visually recognized even on the completed photograph. However, for example, if flash photography is performed when the brightness of a distant background is EV 8.5 or less, and printing is performed so that the main subject obtained by flash photography has an appropriate exposure, the background is darkly crushed on the photograph. In other words, a distant background that is reasonably visible to the human eye becomes completely invisible on the finished photograph.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and in particular, in strobe photography in a large room or outdoors with little illumination, the background is not darkened more than a conventional film unit with a built-in strobe. It is an object to propose a film unit with a built-in strobe lens.

[0011]

The above object is achieved by the following means.

In a film unit having a built-in film and a built-in flash device equipped with a flash device, the shutter speed at the time of flash shooting is SS,
A film unit with a built-in strobe lens, wherein the following conditional expression is satisfied when a guide number in ISO 100 of the strobe device is GNo.

GNo ² / SS <8000

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a film unit with a built-in flash according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is an external perspective view of a film unit with a built-in strobe lens. A photographing lens 1, a finder window 2, a strobe light emitting panel 3, and a strobe switch lever 4 are arranged on the front, a release button 5, an indexer window 6, and a charge display window 7 are arranged on the top, and a winding knob 8 is arranged on the back.
Is arranged. Here, when performing flash photography, when the flash switch lever 4 is slid rightward in the figure, the internal main switch is turned on, and charging of the flash is started. When the internal main capacitor is charged to a predetermined voltage, the charging state can be visually recognized by lighting the charging display window 7. The photographer can press the release button 5 for shooting. When the strobe switch lever 4 is slid rightward as shown in the figure, the tip 4a projects rightward, and it can be easily determined that the main switch has been turned on.

Next, a description will be given, with reference to FIGS. 2 and 3, of a configuration in which the aperture and shutter speed are switched between a normal photographing state in which no flash is used during the daytime and a flash photographing state.

FIG. 2 is a perspective view of a configuration for switching the aperture. Reference numeral 11 denotes an aperture plate, and a large aperture 11a and a small aperture 11b comprising two through holes are provided substantially at the center. In FIG. 1, the large aperture 11a is located behind the taking lens 1 and has, for example, an F-number. The aperture is 6.7.

The strobe switch lever 4 shown in FIG. 1 is fixed to the right arm 11c of the diaphragm plate 11, and two elongated holes 11d formed in the lateral direction of the diaphragm plate 11 are fixed to a fixed body such as a unit body. Guide pins 12 erected from above are fitted. Therefore, by the sliding operation of the strobe switch lever 4, the diaphragm plate 11 slides in the left-right direction. In addition, inverted V-shaped notches 11e and 11f are provided at the lower portion of the diaphragm plate 11, and the inverted V-shaped tip of the leaf spring 13 is pressed against these notches.
It is positioned at several locations.

Reference numeral 15 denotes a strobe unit. Reference numeral 151 denotes a printed circuit board on which a strobe circuit is mounted. Reference numeral 152 denotes a strobe light emitting unit that emits strobe light and emits strobe light from the strobe light panel 3 of FIG. On the back surface of the arm portion 11c of the aperture plate 11, a contact piece 16 whose tip branches into two branches and operates as a main switch of the strobe is provided, and the tip of the contact piece 16 is pressed against the surface of the printed circuit board 151. . Here, in FIG. 2, since the tip of the contact piece 16 is in contact with both the conductive patterns 151a and 151b forming the main switch on the printed circuit board 151, the conductive patterns 151a and 151b are conductive, and The switch is on. Accordingly, the flash is charged and flash photography is possible, and the aperture is the large aperture 11a, which is an open aperture, so that a sufficient flash photography distance can be obtained.

Next, the flash switch lever 4 is slid to slide the aperture plate 11 to the left. Then, the tip of the inverted V-shape of the leaf spring 13 stops in a state of being pressed against the notch 11f, and the small aperture 11 is located behind the photographing lens 1.
b (for example, 12.3 in F number) is located. Further, since the tip of the contact piece 16 is separated from the conductive patterns 151a and 151b on the printed circuit board 151, the conductive patterns 151a and 151b become non-conductive and the main switch is turned off. Accordingly, a photographing state suitable for high-brightness photographing during the daytime or the like is obtained.

With respect to the configuration of the above-mentioned aperture plate 11, a fixed aperture is provided in the optical path of the taking lens L, and the large aperture 1 is provided.
1a is formed to have a diameter larger than the fixed stop,
The portion a may be cut out.

Here, in the film unit with a lens of the present embodiment, the film to be loaded in the manufacturing process in advance is a negative film of ISO800. The taking lens 1 realizes an open aperture of 6.7 in the F number which is a large aperture for a two-piece plastic lens, and the guide number of the strobe is 7 in ISO 100.

The EV value when a film of ISO 100 is used can be expressed by the following equation.

EV = log ₁₀ (F ² / T) / log ₁₀ 2 where F is the F number of the photographing lens at the time of photographing,
T: shutter speed.

Further, in consideration of the ISO sensitivity (S) of a film loaded in advance, an EV value converted into an EV value when using a film of ISO 100 is given by the following equation.

EV = [log ₁₀ (F ² / T) −Log ₁₀
(S / 100)] / Log ₁₀ 2 Therefore, in this specification, an EV value converted to an EV value when a film of ISO 100 is used is defined as an EV value of the reference exposure amount.

In the present embodiment, in daytime shooting using external light without using a flash, the aperture is 12.3 in F number and the shutter speed is 1/80.
The EV value when using a film of ISO 100 is EV1
The value is 3.6, but since the sensitivity of the film is ISO800, the EV value of the reference exposure amount is substantially 10.6.

In flash photography, the aperture is 6.7 in F number, and the guide number of 7 in ISO 100 is 19.8 when converted to ISO 800. Therefore, the shooting distance at which an appropriate exposure is obtained is 19.8 /
6.7 = 3.0 m. That is, an 18% reflector having a reflectance of 18%, which is generally called a standard reflector and which is set based on the reflectance of the average human skin, is referred to as "3.
At 0 m, the reflector is exposed in a properly exposed state.

Incidentally, if it is allowed to underexposure until EV1.5, the maximum photographing distance is 5.1 m. Therefore, a sufficient photographing distance can be obtained despite the use of a small strobe having a smaller guide number, that is, a strobe having a small light amount.

On the other hand, in flash photography, the exposure amount of the background to which the flash light does not reach is 6.
Since the shutter speed is determined only by the aperture of 7 and the shutter speed of 1/80, the EV value when using an ISO 100 film is EV 11.8 from the above equation.
800, the EV value of the reference exposure amount is substantially EV
8.8.

Therefore, the background farther than the maximum photographing distance in the flash photography is exposed at the reference exposure amount of EV8.8, and the latitude of the film is shifted to the underexposure side by E.
Since the V value is about 1.5, the background will not be darkened on the completed photograph up to EV 7.3 which is darker than before.

In addition, when a strobe photographing is performed on a 1.1 m 18% reflective object, the exposure amount of the subject by the strobe light is equivalent to EV 11.5, and the latitude EV of the luminance difference between the background and the ordinary photographic paper is as follows.
It is within 4.5, and both the background of EV7.3 and the subject of 1 m can be reproduced on the print.

When shooting only a dimly lit scene in the morning and evening, there is nothing to do with the flash firing. However, if the flash is in the flash shooting state and the aperture is opened, the image is shot at EV8.8, which is sufficiently appropriate. You can get a picture of the exposure.

As a result of various examinations of these conditions, assuming that the shutter speed at the time of flash photographing is SS and the guide number in the ISO 100 of the flash device is GNo, by satisfying the following conditional expression, it is possible to obtain a large room or lighting. We found that in less outdoor strobe shooting, the background is no longer darker than in conventional film units with built-in strobe lenses.

GNo ² / SS <8000 If the upper limit of this expression is exceeded, the difference between the exposure amount of the strobe light for properly exposing the subject at 2-3 m and the exposure amount of the background due to the external light becomes too large. The background darkens during shooting.

Preferably, GNo ² / SS <650
0, more preferably GNo ² / SS <5000.

Further, as described above, in this embodiment,
Assuming that SS = 1/80 and GNo = 7, GNo ² / SS
= 3920.

As described above, when a film unit with a built-in strobe is configured to be capable of switching between a flash shooting state and a normal shooting state, an aperture value, a shutter speed, a loaded film sensitivity, and a shutter speed in a flash shooting state are set. Where A is the EV value of the reference exposure amount converted to the film sensitivity of ISO 100 determined by
0 is satisfied.

As described above, the EV value of the reference exposure amount can be obtained by the following equation.

EV = [log ₁₀ (F ² / T) −Log ₁₀
(S / 100)] / Log ₁₀ 2 Here, F is the F number of the taking lens, T is the shutter speed (second), and S is the ISO sensitivity of the film.

The F number F of the photographing lens, the shutter speed T (second), and the ISO sensitivity S of the film are respectively
It is desirable to set within the range of F ≧ 5.6, T = 1/80 to 1/30, and S ≧ 640.

It is desirable that the F-number of the photographing lens during flash photography be set to 9 or less so that the condenser capacity of the flash can be reduced as much as possible.

Further, a strobe having a light quantity such that an object at a predetermined distance within a range of 2 to 3 m is properly exposed is selected according to the ISO sensitivity of the film to be loaded and the aperture value in the strobe shooting state.

As described above, a predetermined distance of 18 m
By using a strobe with a light amount that allows the subject composed of the percent reflector to be properly exposed, the light amount of the subject at a distance of 1.1 m, which is the closest shooting distance, becomes A + 3 or less in EV value, and the subject at a distance of 1.1 m And a low-luminance subject having an EV value of A-1.5 are compared with the photographic paper latitude E.
V value can be within a luminance range of 4.5, and 1.1 m
It is possible to simultaneously reproduce a subject within the above-described flash photographable distance range and a subject with a low-luminance background on a print.

It should be noted that, specifically, it is desirable to select a strobe having a guide number of 2 to 9 as a guide number converted into an ISO 100 film so that the capacity of the condenser can be reduced as much as possible.

If the EV value A exceeds 10 under the condition that the EV value in the flash photography state is A, the main subject of 2 to 3 m and the EV of less than or equal to 8.5 in photography under night illumination in the flash photography state. It becomes difficult to obtain a print in which the background of a room with a wide brightness is in a good exposure state. It is desirable that the upper limit of the EV value A is 9.

It is desirable that the lower limit of the EV value A is 6. In order to set the reference exposure amount to low brightness, it is necessary to use a larger-diameter photographing lens, but it is difficult to use a film unit with a lens that is limited in cost, so using a high-sensitivity film It is conceivable to reduce the shutter speed. However, if the shutter speed is reduced, camera shake occurs, and the limit of the shutter speed at which camera shake can be suppressed is generally 1/50. On the other hand, the highest sensitivity color negative film currently on the market is ISO32
00. Therefore, loading this film, for example,
4. Shutter speed to 1/50 and aperture as F number.
If the value is 6, the value becomes EV6, so that the EV value is the limit as the reference exposure amount.

Summarizing these conditions, the EV value A is preferably 6 ≦ A ≦ 10, more preferably 6 ≦ A ≦ 9.

Also, an IS determined by the aperture value, shutter speed, and sensitivity of the loaded film in a normal photographing state.
When the EV value converted to the film sensitivity of O100 is B, it is desirable that B be configured to satisfy the following condition: A + 1 ≦ B ≦ A + 4.

Under the condition of the EV value B in the normal photographing state, if the EV value B falls below the lower limit, if the EV value A in the flash photographing state is set to be smaller than the EV value 8, the EV value B becomes smaller than the EV value B. 9, the exposure is overexposed in outdoor shooting in fine weather.

Therefore, the lower limit of the EV value B of the reference exposure amount in the normal photographing state satisfies the relationship with the EV value A,
In addition, it is desirable to set it to 10 or more.
It is more desirable to set it to 5 or more.

When the EV value B exceeds the upper limit, the EV value B becomes larger than 14 when the EV value A in the flash photography state is set near the upper limit. Will be. Therefore, it is desirable that the upper limit of the EV value B satisfies the relationship with the EV value A and is set to 13 or less.

The EV value A in the flash photography state
And the most desirable range of the EV value B in the normal shooting state is 7 ≦ A ≦ 9 and A + 1 ≦ B ≦ A + 3.

Next, desirable conditions of the photographing lens to be used will be described.

The photographic lens to be used is composed of two lens components and an aperture, and the open F number of the photographic lens is F
_{When “o”} is set, it is desirable that the configuration satisfy the following conditional expression.

5.6 <F _o <8 (1) More preferably, when the condition (1) is satisfied, the half angle of view of the taking lens is ω, and the focal length is f, the following conditional expression is satisfied: Configuration.

5 <f / (F _o · tanω) <7 (2) More preferably, the condition (1) is satisfied, and the F number of the photographing lens is such that the spherical aberration of the marginal ray of F is SA.
Assuming that (F) and half of the length of the photographing screen in the long side direction is y _L , the configuration satisfies the following conditional expression.

[0058] _{-0.072y L <SA (F o /0.7)<-0.024y} L (3) more preferably satisfies the condition (1), the F-number of the photographic lens during flash photography F _{When o} is set and the F-number in the normal shooting state is set to F _off , the following conditional expression is satisfied.

0.4 <F _o / F _off <0.7 (4) More preferably, the conditions of (1) and (4) are satisfied, and the spherical aberration of the marginal ray having the F number of the photographing lens of F is SA. (F), half of the length of the shooting screen in the long side direction is y
_{When L} is set, the configuration satisfies the following conditional expression.

−0.008F _off · y _L <SA (F _o ) <− 0.003F _off · y _L (5) and −0.072y _L <SA (F _o /0.7)<−0.024y _L (6) In the above configuration, each conditional expression will be described. First, when the value exceeds the upper limit of the conditional expression (1), sufficient exposure for a low-luminance subject cannot be obtained. That is, when shooting with a strobe in the shade of a tree, at sunset, or indoors, the amount of strobe light applied to the background, which is a distant subject, is reduced.
Exposure is insufficient and good quality photographs cannot be obtained. In contrast, when the value goes below the lower limit of conditional expression (1),
With two lenses, various aberrations including spherical aberration cannot be sufficiently corrected, and the depth of focus is too shallow, and the effects of curvature of field, errors in back focus during manufacturing, and mounting errors when assembling the lens are large. It is too often that the picture becomes out of focus.

When a photographic lens is formed by using three lenses, unless each lens is provided with an anti-reflection coating, the transmitted light becomes about 79% of the light incident on the lens, and the transmitted light becomes 2% at the refracting surface. The ratio of flare light that reaches the screen after being reflected more than once reaches 2.2% of the transmitted light, which is undesirable. To prevent this, it is necessary to coat at least one lens with an anti-reflection coating, and cost increases can be avoided. Absent. on the other hand,
In the case of two lenses, even without applying an anti-reflection coat,
The transmitted light is about 85%, and the flare light is
It is as small as 0.86%, which is sufficient. Therefore, the lens
Constructing with one piece is cost and lens performance comprehensive,
It is most suitable as a taking lens of a film unit with a lens.

The conditional expression (2) is a condition for obtaining a sufficient depth of field as a fixed focus camera with a taking lens having an open F-number of the conditional expression (1). Conditional expression (2)
If the upper limit is exceeded, the depth of field becomes too shallow, whereas if it falls below the lower limit, the lens becomes too wide-angle, and the peripheral light quantity becomes insufficient due to the cosine fourth law, and the effect of the perspective becomes poor. It is not preferable because it tends to be too large and uncomfortable.

It is preferable that the photographing lens satisfies the conditional expression (3) due to insufficient correction of spherical aberration. When the value exceeds the upper limit of conditional expression (3), spherical aberration is excessively corrected, the center focus position approaches the ideal image plane position, and the difference from the focus position of the off-axis light flux, that is, the influence of the field curvature increases, which is preferable. Absent. Below the lower limit of conditional expression (3), the spherical aberration is too large, which is not preferable.

When the F-number of the lens is changed so as to satisfy the conditional expression (4), overexposure does not occur even in fine weather outdoors where the subject brightness is high, and the F-number decreases when the subject brightness is insufficient indoors. The strobe light reaches even if the guide number of the strobe is relatively small,
Exposure of a subject at a longer distance than the background can be sufficiently obtained. If the upper limit of conditional expression (4) is exceeded, the difference between _Fo and _Foff is too small to obtain a sufficient effect. However, whichever one is selected, it is not preferable because it tends to be inappropriate.

When the condition (4) is satisfied and the above-mentioned photographic lens satisfies the conditional expression (3), it is possible to satisfactorily correct various aberrations at the time of opening as described above.

Further, satisfying the conditions (1) and (4),
If conditional expression (5) is satisfied, an appropriate depth of field can be obtained both when the strobe is used and when it is not used. If the upper limit of conditional expression (5) is exceeded, the open F-number F
spherical aberration is small at the _o, small displacement of the best focus position when focused on F _off, when the auxiliary light by the strobe light so that the depth of field to enter the well within reach when opened, narrowed down to F _off Is not preferable because the resolution of a long-distance object is not sufficiently improved. Conversely, when the value goes below the lower limit of conditional expression (5), the _lens is narrowed down to F _off. The resolution of a short-distance subject cannot be obtained sufficiently.

[0067]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the taking lens will be described below. The symbols in each embodiment are as follows.

F _o : The open F number of the photographing lens, the F number when using the flash F _off : The F number in the normal photographing state f: The focal length of the photographing lens ω: Half angle of view r: The radius of curvature of the refracting surface d: distance between refraction surfaces N _d : refractive index at d-line ν _d : Abbe number y _L : half of the length in the long side direction of the photographing screen U: distance between object and image The aspherical surface used in the present invention The shape is represented by the equation (1), where the coordinate is the x-axis in the optical axis direction and the height in the direction perpendicular to the optical axis is h.

[0069]

(Equation 1)

In Equation 1, K is the conic constant of the aspheric surface, A
_2i indicates an aspheric coefficient (i = 2, 3, 4, 5, 6).

In the figures, ΔS represents sagittal, and ΔM represents meridional.

Example 1 FIG. 3 is a sectional view of a lens optical axis.
FIG. 4 shows a lens aberration diagram. Table 1 shows the lens data.
Shown in

[0073]

[Table 1]

Where f / (F _o · tan ω) = 6.0 SA (F _o /0.7)/y _L = −0.044 F _o / F _off = 0.42 to 0.67 SA (F _o ) / (F _off · y _L ) = − 0.0042 to −
0.0067 FIGS. 5 and 6 show that F _off is 13, the distance between the final surface of the photographing lens and the imaging screen is 25.8 mm, the imaging surface is a cylindrical surface having a radius of curvature of 110 mm, and the aperture is F _o.
FIG. 6 shows MTF diagrams at respective object distances in the long side direction of the screen when “1” is set. Similarly, FIGS. 7 and 8
Shows MTF at each subject distance in the long side direction of the screen when the _aperture is reduced to F _off .

As shown in the MTF diagrams of FIGS. 5 to 8, when the object is open, the focus is good for an object of 1 m to 4 m corresponding to the reach of the strobe. Focus is good from to infinity. In addition, the MTF value itself is sufficient, and a photograph of good image quality can be obtained.

Embodiment 2 FIG. 9 is a sectional view of a lens optical axis.
FIG. 10 shows a lens aberration diagram. Table 2 shows lens data.

[0077]

[Table 2]

Where f / (F _o · tan ω) = 6.16 SA (F _o /0.7)/y _L = −0.044 F _o / F _off = 0.42 to 0.67 SA (F _o ) / (F _off · y _L ) = − 0.0040 to −
0.0064 (Embodiment 3) FIG. 11 is a sectional view of the lens optical axis, and FIG. 12 is a lens aberration diagram. Table 3 shows the lens data.

[0079]

[Table 3]

Where f / (F _o · tan ω) = 6.12 SA (F _o /0.7)/y _L = -0.044 F _o / F _off = 0.42 to 0.67 SA (F _o ) / (F _off · y _L ) = − 0.0040 to −
0.0064

[0081]

According to the film unit with a built-in strobe lens according to the first to sixth aspects of the present invention, it is possible to obtain a photographic image with a dark background and a crushed image, especially in a strobe photographing in a large room or outdoors with little illumination. Less than film unit with built-in lens.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a film unit with a built-in strobe lens.

FIG. 2 is a perspective view of a configuration for switching aperture plates.

FIG. 3 is a sectional view of a lens optical axis according to the first embodiment.

FIG. 4 is a lens aberration diagram of the first embodiment.

5 is a diagram of the MTF at F _o of Example 1.

6 is a diagram of the MTF at F _o of Example 1.

FIG. 7 is a diagram of an MTF at F _{off according to the} first embodiment.

FIG. 8 is a diagram of an MTF at F _{off according to the} first embodiment.

FIG. 9 is a sectional view of a lens optical axis according to a second embodiment.

FIG. 10 is a lens aberration diagram of the second embodiment.

FIG. 11 is a sectional view of a lens optical axis according to a third embodiment.

FIG. 12 is a lens aberration diagram of the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shooting lens 3 Strobe light emission panel 4 Strobe switch lever 11 Aperture plate 11a Large aperture 11b Small aperture 15 Strobe unit 151 Printed circuit board

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03C 3/00 585 G03C 3/00 585Z (72) Inventor Hiroshi Kibayashi 1 Konica Sakuracho, Hino City, Tokyo Stock Association Internal F-term (Reference) 2H053 AA09 AB01 AD13 AD25 BA72 CA41 2H101 AA01 DD24

Claims (6)

[Claims] In a film unit with a built-in film and a built-in flash device equipped with a flash device, when a shutter speed at the time of flash shooting is SS and a guide number in the ISO 100 of the flash device is GNo, Film unit with built-in strobe lens, characterized by satisfying conditional expressions. GNo ² / SS <8000 2. The guide number of the strobe device is 9
2. The film unit with a built-in strobe lens according to claim 1, wherein the film unit is set as follows. 3. A switching operation means for switching between use and non-use of the strobe device, and in conjunction with switching from a use state to a non-use state of the strobe device by the switch operation means, the aperture diameter of the photographing lens is further increased. 3. The film unit with a built-in flash according to claim 1, wherein the film unit is switched to a small aperture. 4. The film unit with a built-in strobe lens according to claim 3, wherein the F-number of the taking lens in the use state of the strobe device is set to 8 or less. 5. The film unit with a built-in strobe lens according to claim 3, wherein an F-number of the photographing lens when the strobe device is not used is set to 10 or more. 6. I in a use state of the strobe device
The film unit with a built-in flash according to any one of claims 1 to 5, wherein the following conditional expression is satisfied, where A is a reference exposure amount converted into a film of SO100. 6 ≦ A ≦ 10