JPH03212626A - Camera provided with trimming function - Google Patents

Abstract

PURPOSE:To prevent out-of-focus by changing the focusing position of a photographing lens in accordance with trimming magnification set by a trimming magnification setting means. CONSTITUTION:By moving a cam plate 6 in a direction shown by an arrow B, a finder variable power lens 5 moves forward by fitting a pin 5a in a cam groove 6a, and an angle of view of finder is changed from a telephoto side to a wide side. Then, the cam plate 6 is stopped at a desired angle of view. The moving quantity of the cam plate 6 hitherto is detected by a pulse plate 7 and an electric armature 8, and the trimming magnification is converted so as to fit to the finder viewing angle by a circuit which is not shown in figure and recorded on a film by a recording means 9. A photographing lens cam barrel 1 is rotated in a direction shown by an arrow A by moving the cam plate 6 and the photographing lens which is not shown in figure is extended by a specified amount. At the same time, a photographing distance consecutive range is displayed by an index 6e and a display plate 10 according to the position of the lens at that time.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention sets a cropping magnification at the time of photographing, and enlarges a part of the photographed film image at the time of printing to a normal screen size using the cropping magnification. The present invention relates to an improvement of a camera with a trimming function that can perform precise zooming.

(Background of the Invention) Conventionally, a so-called pan-focus camera is known which is a low-cost camera and does not change the extending position of a photographic lens depending on the subject distance.

In addition, a cropping magnification is set at the time of shooting, and a portion of the film image taken at the time of printing is enlarged to the normal screen size using the cropping magnification to perform a pseudo zoom, thereby making it possible to obtain a pseudo telephoto photograph. A so-called trimming camera is known.

When the trimming camera is applied to the pan-focus camera, the following problems arise.

When a part of the film image is enlarged according to the set cropping magnification to obtain a pseudo-telephoto photograph, the circle of confusion on the film surface is naturally enlarged, so it is possible to capture images from close range to infinity at a single focal point. In the pan-focus method that covers the depth of field, the blur of objects at close and far distances becomes even thicker. The result is an unsatisfactory photo.

(Object of the Invention) An object of the present invention is to provide a camera with a trimming function that solves the above-mentioned problems and can prevent a photograph from becoming out of focus even if it is enlarged to a desired size by trimming. That's true.

(Features of the Invention) In order to achieve the above object, the present invention includes a setting means for setting a trimming magnification, and a lens driving means for changing the focal position of a photographic lens according to the trimming magnification set by the setting means. The camera is characterized in that the focal length of the photographing lens is changed in accordance with the trimming magnification so that the circle of confusion on the film surface is always small.

(Embodiment of the Invention) FIG. 1 is a perspective view showing the main structure of a camera according to an embodiment of the invention.

In FIG. 1, reference numeral 1 denotes a photographing lens cam barrel, and by rotating around the optical axis, the photographing lens (not shown) in the photographing lens cam barrel is moved by a predetermined amount according to the amount of rotation via a known helicoid or the like. It is a renormalization (rotation in the six directions of arrows is a renormalization).

2 is a film cartridge loaded in a camera body (not shown); 3 is a finder eyepiece; 4 is a finder objective lens; and 5 is a finder magnification lens that changes the finder magnification by moving in the optical axis direction.

Reference numeral 6 denotes a cam plate for moving the finder variable magnification lens 5 back and forth, which is movable in a direction perpendicular to the optical axis, and the bin 5a of the finder variable magnification lens 5 and the cam groove 6a are slidably fitted. There is. Further, a rack 6C is formed on the arm portion 6b, which meshes with the gear portion 1a of the photographing lens cam barrel 1 to rotate the photographing lens cam barrel 1. Furthermore, a shooting distance linked range index 6e is provided on the arm portion 6d. 7 is a pulse plate fixed on the cam plate 6; 8 is the amount of movement of the pulse plate 7;
That is, an electric contact 9 detects the amount of movement of the cam plate 6, and converts the amount of movement of the cam plate 6 detected by the electric contact 8 into a trimming magnification using an electric circuit (not shown), and transmits the information to the film cartridge or It is a recording means for recording on film. Reference numeral 10 denotes a shooting distance linked range display plate, which is fixed to the main body (not shown) and displays the shooting distance linked range to the user in combination with the shooting distance linked index 6e.

The state shown in FIG. 1 is a state in which the trimming magnification is large, that is, a pseudo-telephoto state on the telephoto side.

In the above configuration, when the cam plate 6 is moved in the direction of arrow B manually or by known means, the finder variable magnification lens 5 moves forward due to the engagement of the cam groove 6a and the pin 5a, and the finder The angle of view changes from telephoto to wide. When the desired angle of view is reached, the movement of the cam plate 6 is stopped and the finder angle of view is determined. The amount of movement of the cam plate 6 up to this point is detected by the pulse plate 7 and the electric contact 8, and a circuit (not shown) converts the trimming magnification to match the viewfinder angle of view, and displays the trimming magnification on the film cartridge or film. is recorded by the recording means 9. Further, as the cam plate 6 moves in the direction of arrow B, the photographing lens cam barrel 1 rotates in the six directions of arrows, and the photographing lens (not shown) is retracted by a predetermined amount. At the same time, the photographing distance interlocking range corresponding to the position of the photographing lens at that time is displayed by the index 6e and the photographing distance interlocking range display plate 10.

When the trimming magnification is small, that is, on the wide side, the allowable circle of confusion on the film plane may be large, but when the trimming magnification is large, that is, on the telephoto side (in the state shown in Figure 1), the allowable circle of confusion on the film plane may be large. The permissible circle of confusion must be small. Therefore, with a pan-focus camera, which covers a certain subject distance range with the depth of field, if the circle of confusion on the print after cropping is kept constant, it is necessary to take a photo with a large cropping magnification. The shooting distance linkage range becomes narrower. As a specification for a normal camera, the shooting distance linked range is from a predetermined close distance to infinity.If you simply increase the cropping magnification, the shooting distance linked range will become narrower, so the shooting distance linked range will be limited to a certain close range. This means that the range from infinity to a certain long distance is outside the interlocking range, and the range from a certain short distance to a certain long distance is the interlocking range, but this confuses the user. Therefore, in order to prevent the above-mentioned confusion, it is necessary, for example, to retract the photographic lens and move the focal position toward the long distance side, thereby creating a photographic distance linked range from a certain finite distance to an infinite distance.

For example, photographic lens f = 35mm, F = 4.5
, when the focus is fixed, the trimming magnification is 1x, that is, in the normal shooting mode, the allowable circle of confusion on the film surface is φ0.
09, if the focus position is 3m, the shooting distance linked range is 1.5m.
~Beauty...■ If the cropping magnification is 5x, the allowable circle of confusion on the film surface will be φ0.06, and if the focus position is 4.5m, the shooting distance linked range will be 2.3m - (1)
...■ If the trimming magnification is 2x, the allowable circle of confusion on the film surface will be φ0.045, and if the focus position is 6m, the shooting distance linked range will be 3mNω
It becomes °゛°■.

Therefore, in this embodiment, the helicoid of the photographing lens cam barrel 1 is formed so that the photographing lens moves to the focus position just described according to the trimming magnification.

FIG. 2(a) shows the relationship between the index 6e and the photographing distance linked range display plate 10 in the case of ■. Also, Figure 2 (
b) shows the case of ■, and FIG. 2(c) shows the case of ■.

In this embodiment, the photographic distance linked display is performed using an index and a plate, but the trimming magnification detected from the contact piece 8 and the pulse plate 7 may be displayed using a liquid crystal display or the like using a known electric circuit.

In the example described above, as the cropping magnification increases, the lens focus position is moved to the far side so that infinity is always within the shooting range, but cropping is often used when you want to print a larger portrait of a person. If so, the subject is rarely at infinity, but often within a certain finite distance. Under such a situation, the close distance at a trimming magnification of 1 should always be within the linked distance range even if the trimming magnification changes.

This embodiment is shown in FIG. 3 as another embodiment of the invention.

In FIG. 3, the helicoid of the cam barrel 101 is formed so that the lens extends as the trimming magnification increases.

For example, if the trimming magnification is 1x, that is, in normal shooting mode, and the allowable circle of confusion on the film surface is φ0.09, then if the focus position is 3 m, the shooting distance linked range is 1.5 mN.
cX3...■ If the trimming magnification is 1.2x, the allowable circle of confusion on the film surface is φ0.075, and the focus position is 2.4m.
If set to , the shooting distance linked range is 1.5 to 6.8 m.
...■Trimming magnification month, 5
If it is double, the film surface H saw 乍鐸脩壬l IIH-
? thnnF,? fr nFocus position 2.2m
If set to , the shooting distance linked range will be 1.5m to 4m.
... becomes ■.

Therefore, in this embodiment, the helicoid of the photographing lens cam barrel 101 is formed so that the photographing lens moves to the aforementioned focus position according to the trimming magnification.

FIG. 4(a) shows the relationship between the index 6e and the photographing distance interlocking range display plate lO in the case of ■. Also, Figure 4 (
b) shows the case of ■, and FIG. 4(c) shows the case of ■.

According to this embodiment, since the amount of extension of the photographing lens is changed according to the trimming magnification, the circle of confusion when the subject is within the normal distance can be made smaller on the film surface, and the circle of confusion can be enlarged by trimming. The subject no longer becomes out of focus.

In addition, since the shooting distance linked range display is changed depending on the cropping magnification, the circle of confusion is enlarged due to cropping, and the shooting distance linked range changes, and the photographer is informed of this range, which can eliminate the possibility of taking out-of-focus pictures. Now you can prevent yourself from taking pictures.

(Correspondence between the invention and the embodiments) According to the present embodiment, the finder variable magnification lens 5, the cam plate 6
corresponds to the setting means of the present invention, and the photographing lens cam barrels 1 and 101 and the cam plate 6 correspond to the lens driving means.

(Effects of the Invention) According to the present invention, the present invention includes a setting means for setting a trimming magnification, and a lens driving means for changing the focal position of the photographing lens according to the trimming magnification set by the setting means, and thus, By changing the focal length of the photographic lens according to the cropping magnification, the circle of confusion on the film surface is always small, so even if the image is enlarged to the desired size by cropping, the photo will not be out of focus. It becomes possible to do so.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of the present invention, FIG. 2 is a diagram showing a shooting distance linked range display that is similarly changed according to the selected trimming magnification, and FIG. 3 is a perspective view showing a main part of an embodiment of the present invention. FIG. 4, which is a perspective view showing the main part of another embodiment, is a diagram showing a photographing distance linked range display that is similarly changed according to the selected trimming magnification. 1...Photographing lens cam tube, 5...Finder variable magnification lens, 6...Cam plate, 101...
...Photography lens cam tube.

Claims (2)

[Claims] (1) A camera with a trimming function, which includes a setting means for setting a trimming magnification, and a lens driving means for changing the focal position of a photographic lens according to the trimming magnification set by the setting means. (2) Claim 1, further comprising display means for displaying a shooting distance linked range of the set trimming magnification.
Camera with trimming function as described.