JPS6289922A - Camera with inverted galilean finder - Google Patents

Abstract

PURPOSE:To simplify a constitution by using the object side face of an inverted Galilean finder as a framing mirror as well. CONSTITUTION:Lenses L1-L3 constitute a finder optical system, and each of lenses L1 and L2 is an objective lens having a negative refracting power, and the lens L3 is an oscular lens having a positive refracting power, and they constitute the inverted Galilean finder. A framing frame FR has a visual field frame Fr. An object-side face r1 of the objective lens L1 is projected to the object side, and a optical translucent film H is vapor-deposited on this face to reflect a part of the light incident on the finder optical system, and this face is used for a person P, who exists at the center of a photographic range, to confirm the photographic range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera, and more particularly to a camera having seven wings of the reverse releo type.

2. Description of the Related Art Conventionally, in a disc camera using a disc film, a framing mirror for checking the i-shadow range from the side of the object to be photographed is known. Conventionally, such a framing mirror is placed in the center of the camera, and therefore requires a large space in front of the camera. For example, if you try to install a framing mirror on a 35m+a lens shutter camera, which has a relatively small space on the front, rather than on a camera with a relatively large front space like a disk camera, the front space is limited. Photographic lens, focusing, distance measuring window for distance detection, flash! ffi etc., it is difficult to secure space for a framing mirror, and it is also difficult to design the exterior.

The present invention has been made in view of α as described above, and its purpose is to confirm the range to be photographed from the object side without requiring a special space for arranging a framing mirror. The object of the present invention is to provide a camera that can be used and has a simple configuration.

In order to achieve the above object, the present invention makes the object side surface of the objective lens of an inverted Galilean finder placed on the front side of the camera a semi-transparent surface convex to the object side, and a convex mirror convex to the object side. When viewed from above, it is characterized by being a framing mirror for monitoring the range photographed by the photographing lens.

Therefore, according to the present invention, since the object side surface of the reverse Galileo finder also acts as a framing mirror, there is no need for a special space for a framing mirror, and there is no need to separately provide a member that acts as a framing mirror. The configuration is also easier.

Here, there are two methods to confirm the range to be photographed from the object side. One method is to have a person in the center of the shooting range monitor how much of the surrounding scene is being photographed, and the other is to have the person at the edge of the shooting range and monitor how much of the surrounding scene is being photographed. This is a method of monitoring and confirming whether the image is visible or not.

Below, for each of the two methods, it is
Sympathize.

First, in FIG. 5, (L) indicates a photographing lens, and its focal length is assumed to be r. (F) shows a film, the size of which is 2 a x 2 b. Here, 2a is the size of the film (F) in the direction parallel to the paper surface, 2b is the size of the film (F) in the direction perpendicular to the paper surface, and 2+1
Assume that <213. Then, the angle θa between the light #1 (La) incident on the edge of the film (F) and the optical axis (X) of the photographic lens is θa”a/f ・・・・・・・・・(1
Similarly, for the angle θb in the direction perpendicular to the plane of the paper, θb=b/f River (2).

Next, we will consider the radius of curvature of the object side surface of the objective lens used as a framing mirror, which is required to be 2 cX 2 d (2c<2d) when the radius of curvature is sunk.

First, in the case of the mask method, as shown in figure f:trJ1, the film (F) is Let α be the angle formed by the ray (La) incident on the end, and let β be the angle the eye makes with respect to the object-side surface (r, ) of the objective lens (L, ), then β” c / e Town・...(3) α-
β=c/rl ・・・・・・・・・(4)2
The relationship between the radius of curvature r and the size of the film (F) may be determined so that α-β=θa...machi...(5) holds true. Here, e is the distance from the clothing to the facing objective lens (Ll). Therefore, the above (3) to (
5) Eliminating α and β from the equation, 2c/r1=θa −c/e ・・・・・・・・・
...(6), and since c/e is a very small value, this is ignored, and the relationship 2 c/r-θa...machi...(7) is obtained.

Here, when θa shown in equation (1) is substituted into equation (7), 2c/r1=a/f, that is, is obtained. Here, in reality, the viewing field rate is 8
In order to make it approximately 0% to 90%, the size of the object side surface (rl) of the objective lens (Ll) that constitutes the framing mirror is determined within the range shown by the following equation (9) instead of equation (8). That's fine.

Furthermore, the direction perpendicular to the plane of the paper can be obtained in the same way as equation (9). Therefore, in the case where the film is rectangular as described above, the framing mirror according to this example is a similar shape obtained by proportionally reducing the rectangle, and the above (9) is applied.
It is good if both the conditions of equation (10) are satisfied.

On the other hand, according to the latter method, as is clear from FIG.
1) is directly derived, and also in the direction perpendicular to the paper surface, d/r
,=θb (12) is obtained. Then, convert equations (1) and (2) to (1, 1) respectively.
By substituting into equation (12), we obtain. Here, in reality, the 7 wing field of view rate is 8
In this method, (1
3) Instead of equation (14), the size of the object side surface (rl) of the objective lens (L,) constituting the framing mirror may be determined within the range shown by the following equations (15) and (16). . In this case as well, if the film is rectangular, the framing mirror according to this embodiment may be made to have a similar shape obtained by proportionally reducing the rectangle, and satisfy equation (15H16).

Examples of the present invention will be described below. FIG. 1 is a cross-sectional view showing a 7-point eyeing optical system with a '>1 pre-reflection eyeing according to a first embodiment using the former method of the present invention. In the same figure, (L,) (L2) (L,) constitute a focusing optical system, (Ll) (L2) are objective lenses each having a negative refractive power, and (L,) is a positive refractive power. These are eyepiece lenses having refractive power, and these constitute an inverted 7-eye lens.

(FR) is a 7-frame frame with field of view frame (Fr). Then, the object side surface (rl) of the objective lens (Ll)
) is a convex surface toward the object side, and on top of it is an optical semi-transparent membrane (I4
) is deposited to reflect a portion of the light incident on the 7-eye optical system, and is used by a person (P) in the center of the photographing range to confirm the photographing range.

The specific configuration of this embodiment is shown in Table 1.

Table 1
d) r138.0 (L,) d, 1. ON, 1.
4914r210.5 d24.9 N2 1.0 r, -37,88 (L2) d, 1.0 N)
1.・1914r, 64.14 d40.5 N, 1.0 r7 quintillion' 56.8 (L 3) ds 15.5 N
s 1.4914r6-18.5 d60.5 N, 1.0 ", Tree 2 (1) (FR) d71.I N7 1
．． 515r8 °0 d615. ON, 1.0 Uniform pupil, the surface marked with *1 (r5) is an aspherical surface with ε=1, and this aspherical surface is expressed by taking the X8 mark in the vertical force direction of the optical sleeve and the Φ coordinate in the optical axis direction. When expressed by the following equation, 10, Φ4 185 Φ5+... (17) The aspherical coefficient Δ5 is expressed as Δs''-1, IX10'. However, all the aspheric coefficients other than Δ5 are zero.Furthermore, this surface (r,) is also a reflective surface that reflects the light from the viewing frame.Then, the surface with K2 (r7 ) is the plane on which the field of view frame is provided.The astigmatism and distortion of the 7-eye system of this example are expressed as f
They are shown in Figure 52 (A>(B)).

Next, a second embodiment based on the latter method will be described with reference to FIG. In the figure, (Lo) and (Le) constitute a focusing optical system, (Lo) is an objective lens with negative refractive power, and (Le) is an eyepiece lens with positive refractive power. Similar to the embodiment shown in Fig. 1, the reverse is Lireo 7.
It makes up Aing.

The object-side surface (rl) of the objective lens (Lo) has a convex surface t on the object side, and an optical semi-transparent film (H) is deposited on the surface to prevent light incident on the pointing optical system. A portion of the image is reflected and is used by a person (P) at the edge of the shooting range to confirm the shooting range.

The collaborative structure of this embodiment is shown in Table 2.

Table 2 shows 1 Diopter -1.0 (diopter) Magnification 0.59 Radius of curvature (+++11+) Axis spacing (+nm)
fftJr rate (Nd) r, 35.0 (Lo) d, 1.2 N,
1,49]4rz 10.7 d25. ON2 1. Orz -49,58 (Le) d, 18.3 N,
1.4914r<-20.0 d, 15.0 N,, 1.0 Pupil The non-flashing aberration and distortion of the 7-ing system of this example are
Figures <A) and CB) respectively.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing a 7-ing optical system according to Example 1 of the present invention, Figs. 2 (A) and (B) are aberration diagrams showing astigmatism and wave curvature of the fining system, and Fig. 3 is an embodiment. Cross-sectional views showing the Faing optical system of No. 2, Figures 4 (A) and (B) are No. 7.
FIG. 5 is an aberration diagram showing astigmatism and distortion of the eyeing system, and is a schematic diagram showing the relationship between the focal length of the photographing lens and the photographing range. (L, HLo): Objective lens, (r,): Side surface of the object, (L=) (Le): Eyepiece・ Applicant: Minolta Camera Co., Ltd. Figure 2 (A>$2 Figure 8) Figure 4 (A) Figure 4 (8) Procedural amendment dated December 28, 1985 1. Indication of the case 1985 Patent Application No. 231893 2. Name of the invention Reverse Galileo 7 Camera with Aing 3. Person making the amendment Case Relationship with Applicant Address 2-30 Azuchi-cho, Higashi-ku, Osaka Osaka Kokusai Building Name (607) Mi/Ruta Camera Co., Ltd. Voluntary Amendment 5, Subject of Amendment (1) "Detailed Description of the Invention" column of the specification - 1. 6. Contents of correction (1) In the second line from the bottom of No. 10 of the specification, "in the direction perpendicular to the optical axis" is corrected to "in the direction of the optical axis." (2) In the bottom line of page 10 of the specification, "in the direction of the optical axis" is corrected to "in the direction perpendicular to the optical axis." (3) Correct equation (17) in the eleventh specification as follows. Note: Δ4Φ4+^, Φ5+... Φ=(Y"+Z')"/'...(17) J
(4) On the bottom 4th line of page 10 of the specification, “Here,” and “^
Insert "rco=1/rs," between "other than 5. that's all

Claims (1)

[Claims] 1. In a camera with an inverted Galilean finder, which has an objective lens having negative refractive power and an eyepiece lens having positive refractive power, in order from the object side, the object side surface of the objective lens is convex toward the object side. A camera with an inverted Galilean finder, characterized in that the semi-transparent surface of the camera is a convex mirror that is convex toward the object side, and, when viewed from the object side, is used as a framing mirror for monitoring the range photographed on film by a photographing lens. 2. When the film size is 2a x 2b, the size of the object side of the corresponding objective lens is 2c x 2d, its radius of curvature is r_1, and the focal length of the photographic lens is f, the following conditions must be satisfied. A camera with a reverse Galilean finder according to claim 1, characterized in that: 0<a/f-2c/r_1<0.15 0<b/f-2d/r_1<0.15 However, here, 2a<2b, 2c<2d. 3. When the film size is 2a x 2b, the size of the object side of the corresponding objective lens is 2c x 2d, its radius of curvature is r_1, and the focal length of the photographing lens is f, the following conditions must be satisfied. A camera with a reverse Galilean finder according to claim 1, characterized in that: 0<a/f-c/r_1<0.15 0<b/f-d/r_1<0.15. However, here, 2a<2b and 2c<2d.