JP2000352801A - Film unit with stroboscope built-in lens and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a background from being photographed dark by adopting the constitution to impart such a light quantity that a subject attains adequate exposure by the stroboscope light alone when the subject is placed at a specific distance from a camera to a stroboscope. SOLUTION: A diaphragm plate is provided with an ND filter 21c which is a light transparent type light quantity decreasing means to decrease a transmitted light quantity by uniformly absorbing any wavelength light without the selective absorption of the wavelength of the incident light. The stroboscope is constituted so as to satisfy A<=10 when the reference exposure converted into the film sensitivity of ISO 100 determined from the aperture value in a stroboscope photographic state, a shutter speed and the sensitivity of the loaded film is defined as A. Further, the stroboscope of such a light quantity that the subject of the prescribed distance existing within the range of 2 to 3 m according to the ISO sensitivity of the loaded film and the aperture value in the stroboscope photographic state attains the adequate exposure is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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 same applies to an inexpensive lens shutter camera, and the shutter speed is constant. The taking lens is composed of one or two plastic lenses, and the F value of the open aperture is as dark as about 10. Therefore, when using the film of ISO100, the shooting is limited to the daylight sunny weather.
There are 400 films loaded. It is recommended that an inexpensive camera be loaded with an ISO400 film.

For example, when the shutter speed is set to 1/125,
Assuming that the aperture is 11 in T number in consideration of the transmittance of the lens, the exposure amount in ISO 100 is EV14.
Therefore, when an ISO400 film is used, the EV value becomes 1
2 and relying on the latitude of film or photographic paper, it is possible to shoot from the daytime of fine weather to the 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
Assuming that the shooting distance of the proper exposure is relatively short, 1.8 m, when the T number is set to 11 using the film described above, 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. Another object of the present invention is to provide a camera with a simple mechanism that prevents the background from appearing darker than a conventional camera, especially in stroboscopic photography in a large room or outdoors with little illumination.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to provide an exposure means in a flash photography state in which a reference exposure amount is 1 EV value.
A built-in strobe lens having a strobe for giving a light amount such that the subject is properly exposed only by the strobe light when the subject is placed at a predetermined distance within a range of 2 m to 3 m from the camera. The problem is solved by the attached film unit.

[0012]

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 unit 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 strobe switch lever 4 is slid rightward in the figure, the internal main switch is turned on, and charging of the strobe starts. 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, the aperture switching mechanism will be described with reference to a perspective view of the aperture switching mechanism shown in FIG. In FIG. 1, an aperture plate 21 is disposed behind the taking lens 1. The flash switch lever 4 shown in FIG. 1 is fixed to the right end 21a of the aperture plate 21, and when the flash switch lever 4 is slid left and right, the aperture plate 21 also slides left and right. A flash main switch 22 is disposed below the right end 21a, and a cam 21b is provided below the aperture plate 21. Further, the aperture plate is provided with an ND filter 21c which is a light transmission type light amount reducing means. Here, the ND filter is a so-called neutral gray filter that does not selectively absorb the wavelength of incident light, but has a function of uniformly absorbing any wavelength light and reducing the amount of transmitted light. Things. For example, various products are prepared for a single-lens reflex camera, but have basically the same function. Further, not only the ND filter is inserted into the photographing optical path only when the amount of transmitted light is reduced when the strobe is not fired, but also through the ND filter according to the conditions of the built-in film or the like when the strobe is fired. good. That is, two types of ND filters having different densities are attached to the filter plate, and one having a low density (a large amount of transmitted light) when the strobe is not used and a high density (a small amount of the transmitted light) when the strobe is not used are selected. You may make it.

Therefore, when the filter 21c is inserted behind the taking lens 1 by sliding the diaphragm plate 21 to the left as shown in FIG. 2, the cam 21b is retracted from the main switch 22. The movable contact piece 22a and the fixed contact piece 22b are not in contact with each other, and the main switch 22 is off. In other words, this state is a high-luminance shooting state in which the strobe does not emit light and no strobe shooting is performed.

On the other hand, when the filter 21c is retracted from behind the photographing lens 1 by sliding the diaphragm plate 21 rightward, the diaphragm is a large-diameter fixed diaphragm hole 23a formed in the fixed diaphragm plate 23. The cam 21b presses the movable contact 22a of the main switch 22, and the movable contact 22a
2b, the main switch 22 is turned on. That is, this is a state of flash photography in which a flash is emitted.

Here, in the film unit with 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 7.3 in the T number which is a large aperture for a two-piece plastic lens, and has a focal length of 30 mm. As shown in FIG. 2, when a filter 21c having a substantially smaller aperture diameter is inserted, the T number becomes 13.4. The shutter speed of a shutter (not shown) is 1/80, and the guide number of the strobe is 7 in ISO100.

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

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

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

EV = [log ₁₀ F ² + log ₁₀ (1 /
T) −log ₁₀ (S / 100)] / log ₁₀ 2 Therefore, in this specification, the EV value converted to the EV value when a film of ISO 100 is used is defined as the EV value of the reference exposure amount.

In the present embodiment, the aperture is set to 13.
4. Since the shutter speed is 1/80,
Is EV13.9 when the film No. is used, but since the sensitivity of the film is ISO800, the EV value of the reference exposure amount is substantially EV10.9.

In flash photography, the aperture is 7.3 in T 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 /
7.3 = 2.7 m. That is, an 18% reflector having a reflectance of 18%, which is generally called a standard reflector and is set based on the reflectance of the skin of an average person, is referred to as “2.
When placed at 7 m, this reflector is exposed in a properly exposed state.

Incidentally, if it is allowed to underexposure until EV1.5, the maximum photographing distance is 4.6 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 7.
Since the shutter speed is determined only by the aperture of 3 and the shutter speed of 1/80, the EV value when using a film of ISO100 is EV12.1 from the above equation.
800, the EV value of the reference exposure amount is substantially EV
9.1.

Therefore, the background farther than the maximum photographing distance in the flash photographing is exposed at the reference exposure amount of EV9.1, and the latitude of the film is shifted toward the underexposed side by E.
Since the V value is about 1.5, the background will not be darkened on the completed photograph up to EV7.6 which is darker than the conventional one.

In a film unit with a lens, the closest distance for photographing is usually set to 1 m.
The exposure amount of the subject by the strobe light in the case of performing the flash photography with respect to the subject of the 18% reflective plate of m is equivalent to EV12, the luminance difference from the background is within the latitude EV4.5 of ordinary photographic paper, and EV7.6. Can be reproduced on the print.

When shooting only a dimly lit scene in the morning and evening, it does not matter at all whether the flash fires. However, if the aperture is set to the flash shooting state and the aperture is opened, the image is shot in EV9.1, which is sufficiently appropriate You can get a picture of the exposure.

As described above, when the film unit with a built-in flash is configured to be able to switch between the flash shooting state and the normal shooting state, the aperture value, the shutter speed, the sensitivity of the loaded film and the aperture value in the flash shooting state are set. When the EV value of the reference exposure amount converted into the film sensitivity of ISO 100 determined by the formula is A, A is configured to satisfy A ≦ 10.

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

EV = [log ₁₀ F ² + log ₁₀ (1 /
T) -log ₁₀ (S / 100)] / log ₁₀ 2 where F is the T number of the taking lens, T is the shutter speed (second), and S is the ISO sensitivity of the film.

The T number F of the taking 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 ≦ 1/50 and S ≧ 640.

It is desirable to set the T-number of the taking lens at the time of flash photography to 11 or less, preferably 9 or less so that the condenser capacity of the flash can be made as small as possible.

Further, a strobe having a light amount such that an object at a predetermined distance within a range of 2 to 3 m is properly exposed is selected in accordance with the ISO sensitivity of the film to be loaded and the aperture value in the strobe photographing 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 8 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 T 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. Further, when an EV value converted into a film sensitivity of ISO 100 determined by an aperture value, a shutter speed and a sensitivity of a loaded film in a normal photographing state is B, B satisfies A + 1 ≦ B ≦ A + 4. It is desirable to configure.

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 8. 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. Although the example in which the concept of the present invention is applied to a film unit with a lens has been described, this technique can be similarly applied to a camera, particularly an inexpensive camera. For example, even a camera as shown in FIG. 3 incorporates the same mechanism as the above-described lens-equipped film unit, thereby enabling balanced shooting. In addition, a photographing lens 31, a finder window 32, a strobe light emitting unit 33, and a strobe switch lever 34 are arranged on the front, and a release button 35, an exponent window 36, a charge display window 37, and a rewind handle 38 are arranged on the top. The hoist knob 39 is arranged on the back. In this camera, manual film winding is used, but of course, electric film feeding may be used. In general, in a lens shutter camera, photometry and distance measurement are performed by electronic control, and an optimum aperture value and focus are determined based on a calculation result. However, there is a problem that a product cost increases. In contrast, as in the present invention,
A mechanism for reducing the amount of transmitted light or increasing the shutter speed when the strobe is not emitting light is inexpensive and has few failures, and is a technology that can be easily applied to a camera.

[0044]

According to the film unit with a built-in strobe and the camera according to any one of the first to tenth aspects, it is possible to obtain a crushed photograph with a dark background, particularly in a strobe photographing in a large room or outdoors with little illumination. Film unit with built-in strobe lens and camera.

[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 diaphragm plate and the like.

FIG. 3 is a perspective view of a camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shooting lens 3 Strobe light emitting unit 4 Strobe switch lever 21 Aperture plate 21c Filter 22 Main switch 23 Fixed aperture plate 23a Fixed aperture hole

Claims (10)

[Claims] 1. A film unit with a built-in strobe lens, wherein a reference exposure amount is 10 or more as an EV value by an exposure unit in a strobe shooting state, and a reference exposure amount is 10 or less as an EV value by an exposure unit in a strobe shooting state. A switching means for switching between the flash photography state and the normal photography state; and a light transmission type light quantity in which the transmission light quantity of the photographing lens is reduced by switching the strobe from a light emitting state to a non-light emitting state in conjunction with the switching means. The strobe is set so as to provide a light amount such that the subject is properly exposed only by the strobe light when the subject is placed at a predetermined distance within a range of 2 m to 3 m from the camera. A film unit with a built-in strobe lens. 2. The film unit according to claim 1, wherein the object is an 18% reflector. 3. The film unit with a built-in strobe lens according to claim 1, wherein the EV value is 9 or less. 4. The film unit with a built-in strobe lens according to claim 1, wherein the EV value is 6 or more. 5. The film unit with a built-in strobe lens according to claim 1, wherein the T number of the taking lens in the strobe shooting state is 5.6 or more and 11 or less. . 6. A camera with a built-in strobe, wherein a reference exposure amount is 10 or more as an EV value by an exposure unit in a strobe shooting state, and a reference exposure amount is 10 or less as an EV value by an exposure unit in a strobe shooting state. Switching means for switching between a flash photography state and a normal photography state; and a light transmission type light quantity reduction means for reducing the transmitted light quantity of the photographing lens by switching the strobe from a light emitting state to a non-light emitting state in conjunction with the switching means. Wherein the strobe is set so as to provide a light amount such that the subject is properly exposed only by the strobe light when the subject is placed at a predetermined distance within a range of 2 m to 3 m from the camera. A lens camera with a built-in flash. 7. The camera according to claim 6, wherein the object is an 18% reflector. 8. The camera according to claim 6, wherein the EV value is 9 or less. 9. The camera with a built-in strobe according to claim 6, wherein the EV value is 6 or more. 10. The camera with a built-in flash according to claim 6, wherein a T-number of the taking lens in the flash shooting state is 5.6 or more and 11 or less.