JP2000147378A - Close-up lens and close-up photographing auxiliary device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a close-up lens used with a camera such as a digital camera and capable of performing such macro-photographing as the photographing of an image stored in a developed film. SOLUTION: This close-up lens is arranged in front of the photographing lens of the camera and constituted of a negative first lens group and a positive second lens group in order from an object side. In this case, when lens total length of the close-up lens is defined as L, and the focal distance is defined as (f), the expression of 0.4<L/f<1.0 is satisfied. And when the photographing magnification in the case of close-up photographing is defined as (m), and the magnification of the close-up lens is defined as(mc), the expression of |m/mc|<0.04 is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a close-up lens and a close-up photographing assisting device which are used in front of a photographing lens of a camera to perform close-up photographing.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers and higher performance,
There is an increasing demand for image data capture, and there is a growing demand for digital cameras, film scanners for capturing images stored on silver halide films, and flatbed scanners. Some digital cameras have a macro shooting function, and an adapter for macro shooting that is attached to the front of the shooting lens is also commercially available.

[0003]

However, the macro photographing function and the macro photographing adapter of the digital camera are not designed for photographing developed J135 film or IX240 film. However, the photographing magnification and photographing performance are not sufficient, and the performance comparable to the above-described film scanner or the like has not been obtained. On the other hand, a film scanner or the like can obtain a sufficient image quality because it is made only for reading a so-called hard copy image such as a film, but its use is limited to reading a hard image.

The present invention has been made to solve the above problems. In particular, a digital camera or a camera using a silver halide film can be carried, and a close-up lens and a close-up photographing auxiliary which are suitable for use with the camera and which enable macro photographing of an image stored in a developed film. An apparatus is provided.

[0005]

The object of the present invention is achieved by adopting the following constitution.

That is, the close-up lens of the present invention is:
A close-up lens composed of a negative first lens group and a positive second lens group in that order from the object side and used in front of a photographing lens of a camera. Assuming that L and the focal length are f, the zoom lens is configured to satisfy the following conditional expression.

0.4 <L / f <1.0 (1) More preferably, when the photographing magnification at the time of close-up photographing is m and the magnification of the close-up lens is mc,
It is configured so as to satisfy the following conditional expression.

| M / mc | <0.04 (2) More preferably, the first lens group includes a negative meniscus lens having a convex surface facing the object side, and the image-side curvature of the meniscus lens. Assuming that the radius is Rm, the configuration is such that the following conditional expression is satisfied.

0.3 <Rm / L <0.8 (3) More preferably, the second lens group comprises at least two positive lenses and one negative lens, and If the focal length of f is set to f2, the following conditional expression is satisfied.

0.5 <f2 / f <0.9 (4) Further, the paraxial ray height of the object side surface, which is used in front of the taking lens of the camera, is hF, and the camera is When hE is the paraxial ray height of the surface on the side of the taking lens of 0 <hF / h
A close-up lens that satisfies E / 1, where L is the total lens length of the close-up lens and f is the focal length, so that the following conditional expression is satisfied.

0.4 <L / f <1.0 (1) The close-up photographing assisting device according to the present invention includes the above-described close-up lens and holding means for holding the developed silver halide film. Illuminating means for illuminating the silver halide film.

[0012] The image forming apparatus further comprises a holding means for holding the developed film, an illuminating means for illuminating the film held by the holding means, and a close-up lens. By arranging a close-up lens to face and using a photographic lens of a camera behind the close-up lens with respect to the holding unit, the image of the film illuminated by the illuminating unit is closed. A close-up photographing assisting device that enables photographing by enlarging with an up-lens, wherein an image surface of the film is disposed near an object-side focal position of the close-up lens, and a photographing lens of the camera is positioned at a long distance. It is configured to be used in a state of being scorched.

More preferably, in the close-up photographing assisting device, the photographing magnification in close-up photographing is m, the focal length of the close-up lens is f, and the exit pupil diameter is D.
If e is set, the following conditional expression is satisfied.

1.2 <fm / De <4.0 (5) More preferably, the close-up lens is composed of a negative first lens unit and a positive second lens unit in order from the object side. When the total lens length of the close-up lens is L and the focal length is f, the following conditional expression is satisfied.

0.4 <L / f <1.0 (1) In the above-described configuration, the first and second negative lens units and the second positive lens unit are arranged in order from the object side, thereby distorting the lens. It becomes possible to correct aberration, chromatic aberration of magnification, and field curvature. Conditional expression (1) relates to the distance between the negative first lens group and the positive second lens group. Becomes too large to correct spherical aberration, coma and astigmatism satisfactorily. If the upper limit is exceeded, the lens diameter, especially the diameter of the first lens group, increases rapidly, and the cost increases. And the distance between the close-up lens and the subject becomes too short, making it difficult to use.

Further, conditional expression (2) relates to the use state of the close-up lens of the present invention, and is intended to sufficiently bring out the optical performance of the photographing lens of the camera that performs close-up photographing. When the value exceeds the upper and lower limits of the conditional expression (2), the photographing magnification of the camera that performs close-up photographing deviates from that in normal use, and generally the performance is deteriorated, which is not preferable. Further, as will be described later, the arrangement accuracy of the close-up lens and the photographing lens, particularly, the shift of the optical axis and the eccentricity of the tilt are easily affected, which is not preferable.

If the value exceeds the upper limit of conditional expression (3), positive distortion occurs during close-up photographing, which is not preferable. If the value is below the lower limit, coma and astigmatism increase, which is not preferable.

If the second lens group is composed of two or more positive lenses and one or more negative lenses, the Petzval sum can be reduced, and the occurrence of field curvature can be reduced. If the lower limit of conditional expression (4) is exceeded, it will be difficult to correct spherical aberration and coma, making it difficult to apply the present invention to a bright photographing lens having a small F-number. Conversely, if the upper limit is exceeded, the distance between the close-up lens and the subject becomes too small, which is not preferable.

When the paraxial ray height of the object-side surface is hF and the paraxial ray height of the camera-side lens surface is hE, a close-up satisfying 0 <hF / hE <1. When the lens is configured, if the lower limit of conditional expression (1) is exceeded, the refractive power of the constituent lens tends to be large, and spherical aberration, coma and astigmatism cannot be corrected well. If the upper limit is exceeded, the diameter of the lens, particularly the diameter of the lens surface on the object side, increases rapidly, causing an increase in cost, and the distance between the close-up lens and the subject becomes too short, making it difficult to use.

The conditional expression (5) relates to the F-number of the close-up lens viewed from the photographing lens side.
When the camera is mounted for close-up shooting with a large number and there is not enough aperture, if both optical axes shift slightly, the light beam incident on the shooting lens may be shaken by the close-up lens or close-up If the ray paths passing through the lens are different and coma flare is not sufficiently corrected at the edge of the entrance pupil, the field curvature and astigmatism in the connected state greatly fluctuate, which is not preferable. Conversely, when the value is below the lower limit, the F-number of the close-up lens is small, and the number of lens components increases or the lens diameter becomes too large to sufficiently correct aberration, which is not preferable.

Further, the close-up lens is provided as a first aspect.
In this case, a close-up photographing assisting device having good imaging performance can be obtained.

[0022]

Examples of the close-up lens of the present invention will be described below. The symbols in the examples are as follows.

F: focal length of the close-up lens De: exit pupil diameter of the close-up lens ω: half angle of view r: radius of curvature of the refraction surface d: interval between the refraction surfaces Nd: refractive index of lens material at d-line νd : Abbe number of lens material f2: Focal length of the second lens group of the close-up lens m: Magnification of the entire system in close-up shooting mc: Magnification of the close-up lens in close-up shooting L: Total length of the close-up lens In each embodiment, the focal length is 6.9 mm, and the F number is 3.
2. A close-up lens for a photographing lens having a half angle of view of 32 ° and a photographing magnification of −0.195.

FIGS. 1 (a), 2 (a) and 3 (a) are sectional views of the lenses of the first, second and third embodiments.
1 (b), 2 (b) and 3 (b) are aberration diagrams of the lenses of the first, second and third embodiments, respectively, and show the focal length at the exit pupil of the close-up lens of the present invention. Is 6.9
When a close-up photographing with a photographing magnification of -0.195 times is performed with an ideal lens having a diameter of 0.1 mm, a lateral aberration diagram at the center and at an image height of 70%, and the exit pupil diameter is described in the table of each embodiment. It is. 1 (c), 2 (c) and 3 (c) show the distortion of the lenses of the first, second and third embodiments.

Embodiment 1

[0026]

[Table 1]

L / f = 0.93 m / mc = 0 Rm / L = 0.46 f2 / f = 0.74 fm / De = 2.04 Embodiment 2

[0028]

[Table 2]

L / f = 0.51 m / mc = 0 Rm / L = 0.62 f2 / f = 0.58 fm / De = 2.04 Embodiment 3

[0030]

[Table 3]

L / f = 0.64 m / mc = 0 Rm / L = 0.51 f2 / f = 0.56 fm / De = 2.04

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a close-up photographing assisting apparatus according to the present invention will be described in detail with reference to FIGS. 4 and 5, but the present invention is limited to the embodiment described below. Not something.

FIG. 4 is a diagram for explaining the configuration of the close-up photographing assisting apparatus according to the present embodiment. FIG. 5 is a diagram illustrating the influence of tilt between the close-up lens and the photographing lens when the close-up lens is used.

In FIG. 4, reference numeral 1 denotes a close-up photographing assisting device. The position of the close-up photographing assisting device 1 in the close-up lens holding frame H is fixed to the close-up lens 11 by a film holding portion 13. The developed film 12 is held. An illuminator L is arranged behind the illuminator to illuminate the film 12. The image of the film 12 formed by the close-up lens 11 is almost infinity because the image plane of the film is near the focal position of the close-up lens. The image is formed on the photosensitive unit 15 such as a CCD or a film by the photographing lens 14 focused on.

The exit pupil diameter of the close-up lens 11 is
It is larger than the entrance pupil diameter of the photographing lens 14, and a part of the light beam that has passed through the close-up lens 11 is
An image on the photosensitive section 15 is formed. Film 12
The illuminating unit L behind is a light emitting unit 16 such as a fluorescent lamp or a cold cathode tube.
, Diffusion plate 17 and close-up lens 11 if necessary
Lens 18 for adjusting the amount of light incident on the lens
It consists of.

In this state, the developed film is illuminated from behind, the image plane of the film is arranged near the object side focal position of the close-up lens, and the photographing lens of the camera is focused at a long distance. In this case, the image of the film by the close-up lens can be set at infinity, so that the image can be taken as a subject of the camera.

The tilt relationship between the close-up lens and the photographing lens at this time will be described with reference to FIG. In FIG. 5, Q
PR indicates a virtual image formed by a close-up lens of a planar object such as a film. At this time, it is assumed that the close-up lens faces the planar object. In the figure, the close-up lens is omitted, and the image QP
Only R is drawn. The image obtained by the taking lens having the image QPR as an object is Q'P'R '. When the camera C in FIG. 4 is tilted by θ with respect to the image QPR by the close-up lens, Q is reduced according to the Scheimpflug condition as shown in FIG.
An image Q'P'R 'of the PR taking lens is obtained. However, the imaging plane of the camera is at Q "P'R" and the image is θ '
Only the tilt is out of focus.

From FIG. It becomes the relationship.

With the configuration according to the present invention, the magnification of the photographing lens is substantially zero, and the inclination of the image with respect to the optical axis of the camera lens can be substantially zero. Therefore, when the camera is attached to the close-up photographing assisting device of the present invention, even if the optical axis of the close-up lens and the photographing lens of the camera is slightly tilted, the image plane is not tilted and no blur occurs. As a result, it is possible to obtain an easy-to-handle close-up photographing assistance device.

[0040]

As described above, the close-up lens and the close-up photographing assisting device according to the present invention have good image forming performance as shown in the aberration diagram. Because it is used at a good magnification, close-up shooting with good image quality can be performed. Further, since the connection with the camera is configured so as not to require much accuracy, it is possible to use a close-up photographing auxiliary device which can be used without being influenced by the exterior of the camera and which is easy to use. With the use of the close-up lens and the close-up photographing assist device, a digital still camera or the like can be easily used as a film scanner or the like.

[Brief description of the drawings]

FIG. 1 is a sectional view and an aberration diagram of a lens according to a first embodiment.

FIG. 2 is a sectional view and an aberration diagram of a lens according to a second embodiment.

FIG. 3 is a sectional view and an aberration diagram of a lens according to a third embodiment.

FIG. 4 is a configuration diagram of a close-up photographing assistance device.

FIG. 5 is an explanatory diagram of the influence of tilt between a close-up lens and a photographing lens.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Close-up photography auxiliary device 11 Close-up lens 12 Film 13 Film holding part 14 Photo-taking lens 15 Photosensitive part 16 Light-emitting part 17 Diffusing plate 18 Condenser lens C Camera H Close-up lens holding frame L Lighting part

Continued on the front page F term (reference) 2H087 KA02 KA03 LA21 MA01 PA03 PA04 PA17 PA18 PB04 QA02 QA06 QA07 QA17 QA21 QA22 QA25 QA26 QA32 QA34 QA41 QA42 QA45 QA46 2H101 EE01 2H105 CC02 9A001 KK16

Claims (9)

[Claims] 1. A close-up lens comprising a negative first lens group and a positive second lens group in order from the object side, which is disposed in front of a photographing lens of a camera, and
A close-up lens characterized by satisfying the following conditional expression, where L is the total lens length of the close-up lens, and f is the focal length. 0.4 <L / f <1.0 2. The photographing magnification at the time of close-up photographing is m,
The close-up lens according to claim 1, wherein the following conditional expression is satisfied, where mc is the magnification of the close-up lens. | M / mc | <0.04 3. The lens system according to claim 1, wherein the first lens group comprises a negative meniscus lens having a convex surface facing the object side, and the following conditional expression is satisfied when a radius of curvature of the meniscus lens on the image side is Rm. The close-up lens according to claim 1 or 2, wherein 0.3 <Rm / L <0.8 4. The second lens group comprises at least two positive lenses and one negative lens, and satisfies the following conditional expression if the focal length of the second lens group is f2. The close-up lens according to claim 1. 0.5 <f2 / f <0.9 5. The paraxial ray height of the object-side surface, which is used in front of the taking lens of the camera, is hF, and the paraxial ray height of the surface of the taking lens side of the camera is hE. Then 0
<A close-up lens satisfying hF / hE / 1, wherein the following conditional expression is satisfied, where L is the total lens length of the close-up lens, and f is the focal length. 0.4 <L / f <1.0 6. A close-up lens comprising: the close-up lens according to claim 1; holding means for holding a developed silver halide film; and lighting means for illuminating the silver halide film. Up shooting assistance device. 7. A holding device for holding a developed film, an illuminating device for illuminating the film held by the holding device, and a close-up lens, wherein the illuminating device and the illuminating device sandwich the holding device. By arranging a close-up lens to face and using a photographic lens of a camera behind the close-up lens with respect to the holding unit, the image of the film illuminated by the illuminating unit is closed. A close-up photographing assisting device that enables photographing by enlarging with an up-lens, wherein an image surface of the film is disposed near an object-side focal position of the close-up lens, and a photographing lens of the camera is positioned at a long distance. A close-up photographing assisting device characterized in that it is used in a state of being focused. 8. A photographing magnification at the time of close-up photographing is m,
8. The close-up photographing assisting apparatus according to claim 7, wherein the following conditional expression is satisfied, where f is a focal length of the close-up lens and De is an exit pupil diameter. 1.2 <fm / De <4.0 9. The close-up lens is composed of a negative first lens group and a positive second lens group in this order from the object side. When the total lens length of the close-up lens is L and the focal length is f, 9. The close-up photographing assisting device according to claim 7, wherein a conditional expression is satisfied. 0.4 <L / f <1.0