Photography – Disposable or recyclable camera
Reexamination Certificate
1999-10-25
2001-04-24
Perkey, W. B. (Department: 2851)
Photography
Disposable or recyclable camera
C396S155000, C396S213000, C396S458000, C396S563000
Reexamination Certificate
active
06222995
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens-fitted photo film unit containing a roll of unexposed photo film and having simple photographic mechanisms incorporated therein, and a method of making photo-prints. Particularly, the present invention relates to a lens fitted-photo film unit having a flash device and being suited for indoor- and night-photography, and a method of making photo-prints from picture frames photographed by that lens-fitted photo film unit.
2. Background Arts
A variety of lens-fitted photo film units, hereinafter referred to as film units, have been developed and marketed. Many of them have a flash device so that it is possible to take photographs at night or indoors where the subject is too dark for photography.
Because most of the conventional film units have a fixed shutter speed, a fixed aperture size and a film speed, these values are suited for daylight photography. On the other hand, the flash device is so designed that a main subject in a range from about 1 m to 4 m is illuminated suitably.
Since the film unit is basically adjusted to daylight photography, a picture photographed with a flashlight by the film unit tends to contain an over-exposed main subject and an under-exposed background. Moreover, a picture taken by the film unit with the flashlight in a room illuminated by fluorescent lights will be tinged with an ugly greenish hue in those portions where the flash does not reach, when it is printed on the basis of a color temperature of the flashlight. This is because the color temperature of the flashlight is different from that of the fluorescent light.
Specifically, although the fluorescent light is visually a white light or around, and the object illuminated by the fluorescent light visually shows its object color, photosensitive layers for green of most kinds of photo films are more sensitive to the fluorescent light than other color photosensitive layers. On the other hand, the flashlight is almost neutral for spectral sensitivity of the photo film. As a result, the background illuminated by the fluorescent light alone will be tinged with the ugly greenish hue, called ugly green, when printed without any color correction.
If, on the contrary, that picture is printed on the basis of the color temperature of the fluorescent light, and if there is a human subject, the magenta hue of the flesh color becomes so strong that the human subject looks like drunken. This is because magenta, the complementary color to green, is enhanced in the whole area of the picture to cancel the greenish hue.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide a film unit by which it is possible to photograph both the main subject and the background at adequate exposure conditions either in daylight photography or in flash-photography.
Another object of the present invention is to provide a film unit that can take a negative frame from which a photo-print of adequate color reproductions and density gradations may be obtained, even if the negative frame is photographed with the flashlight under fluorescent lighting or in a dark place. Providing a printing method for the film unit of the present invention is also an object of the present invention.
A further object of the present invention is to provide a method of making photo-prints, by which high-quality photo-prints are produced from picture frames photographed by the film unit of the present invention.
The above objects will be achieved when the film unit satisfies the following requirements:
1) The background is photographed at a tolerable exposure level.
2) The main subject is photographed at an adequate exposure level.
3) Out-of-focus range excluded from the depth of field is within a permissible range, while the handshake is restricted to a tolerable degree.
4) Color reproduction of flesh color of a main human subject is adequate.
5) The failure due to under-exposure is reduced.
Concerning the fifth requirement, it is possible to take some measure for this requirement in the printing stage, instead of or in addition to taking some measure on the film unit.
In order to satisfy the first requirement, the inventor of the present invention first made a research on photographic circumstances wherein ordinary users of the film units take photographs. As a result, it was found that illuminance of backgrounds was not less than 75 lx in most indoor- and night-photographs. Then, experiments were made to determine how much system sensitivity is necessary for the film unit in order to obtain satisfactory photo-prints when the pictures are taken in such indoor circumstances. Specifically, twenty typical indoor scenes were photographed by each of six samples having different system sensitivities.
System sensitivity is defined by the following formula:
2log
2
(A)+log
2
(1/T)−log
2
(0.3·S)
wherein A represents an aperture size, T represents a shutter speed in the unit of second, and S represents an ISO sensitivity or film speed.
In the experiments, the six samples had the same film speed S of ISO800 and the same aperture size A of F5.6, whereas the shutter speed T was changed gradually from each other. The photographed pictures were developed and printed in a standard photographic process, and each of consequent photo-prints was examined as to whether the main subject and the background were adequately reproduced. The results of the examination are shown in Table 1.
TABLE 1
RATE OF ADEQUATE
SYSTEM SENSITIVITY
PRINTS
−8
5%
−4
70%
0
85%
2
95%
4
50%
6
5%
According to the results of the examination, it was proved that the main subject and the background may be photographed adequately in most scenes when the system sensitivity was in a range from −5 to 5, and more preferably from −2 to 4. When the system sensitivity was in a range from 1 to 3, almost all scenes were photographed adequately.
Accordingly, to satisfy the first requirement, the system sensitivity of the film unit of the present invention is defined in the range from −6 to 5, more preferably from −2 to 4, and most preferably from 1 to 3.
Since the above conditions of the system sensitivity are suited for indoor- or night-photography, the film unit of this system sensitivity can not always take adequate photographs in daylight or under sufficiently bright lighting. Therefore, it is preferable to mount an exposure control mechanism in the film unit that allows switching over the system sensitivity of the film unit by manually or automatically changing the aperture size A or the shutter speed T. Thereby the exposure amount may be controlled according to the photographic circumstances, e.g., depending upon whether it is indoor- or night-photography or daylight-photography. The easiest way to change the system sensitivity is to switch over the aperture size A and/or the shutter speed T between two different values each in cooperation with an ON-OFF operation for the flash device. In that case, the aperture size A should be enlarged or the shutter speed T should be increased when the flash device is turned off. An exposure control mechanism that switches over the aperture size in cooperation with the ON-OFF operation of the flash device is disclosed for example in JPU 1-130110.
To satisfy the second requirement, the film unit should preferably be provided with a flash device that projects an appropriate amount of flashlight, or guide number of the flash device is optimum. Light distribution characteristics of the flash device are also important. In results of intensive examinations of the inventor, it was proved that the second requirement was satisfied when the illuminating angle of the flash device is widened. Specifically, as shown in
FIG. 12
, the illuminating angle is widened such that the amount of flashlight at points P2 and P3, which are located on an object plane above and below a photographic field
80
, is not less than 60% of the amount of flashlight at a center point P1 of the photographic field
80
. The point
Fuji Photo Film Co. , Ltd.
Perkey W. B.
Young & Thompson
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