JPH04113307A - Toric lens and camera - Google Patents

Abstract

PURPOSE:To obtain a new toric lens and camera which are dedicated to toric photography by mounting a 1st and a 2nd toric lens or cylinder lens, and a 3rd lens which is symmetrical about the optical axis. CONSTITUTION:The toric lens is constituted by arranging the 1st-3rd lenses in order from the object side to the image side. The 1st lens 10 has negative refracting power, the 2nd and 3rd lenses 12 and 14 have positive refracting power, and the 3rd lens is symmetrical about the optical axis and has a difference between the meridional focal length and sagittal focal length. Then f1+f2 D holds, where f1 is the focal length of the 1st lens, f2 is the focal length of the 2nd lens, and D is the interval between the principal points of the 1st and 2nd lenses. Further, 0<K5<1.5 and 1<K6<3 hold for the cone coefficient K5 of the aspherical surface of the 3rd lens on the object side and the cone constant K6 of the aspherical surface on the image side while the lens surfaces of the 3rd lens on the object and image sides are both aspherical. The camera is fitted with the 1st-3rd toric lenses and is rotatably on the optical axis of those lenses.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a trick lens, that is, a lens and camera for taking photographs with different vertical and horizontal scales.

[Prior Art] So-called 1-link photos with different vertical and horizontal scales have been known for a long time. Conventionally, such 1-link photos have been taken by equipping a camera with a special lens, and lenses and cameras dedicated to trick photography have not been put to practical use.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a new trick lens and camera exclusively for 1-link photography.

[Means for Solving the Problems] The trick lens of the present invention is a lens that has "different focal lengths in the meridional direction and in the spherical direction."

This trick lens has a first lens from the object side to the image side.
The first lens has a negative refractive power, the second lens has a negative refractive power, and the second lens has a negative refractive power. The third lens has positive refractive power, the first and second lenses are h-link lenses or cylinder lenses, and the third lens is an optical axis symmetrical lens (claim 1).

The third lens being symmetrical about the optical axis means that the imaging performance of the third lens is rotationally symmetrical about the optical axis. When the focal length of the two lenses is f2, and the distance between the principal points of the first and second lenses is D, these are (I) fr
The trick lens according to claim 3, characterized by the condition: The conic constant of the aspheric surface is 6 (II) 0 (X5(1,,5(III)
], < KG < 3. The camera according to claim 4 has the trick lens according to claim 1, 2, or 3 above.

In the camera of the present invention, first. The second lens can be made rotatable around the optical axis of the third lens (claim 5).

Further, in the camera according to claim 4 or 5, the lens surface of the third lens of the trick lens is aspherical on both the object side and the image side, and the conic coefficient of the aspherical surface of the object side lens surface is 5, and the conic coefficient of the aspherical surface of the image side lens surface is 5. The conic constant of the aspherical surface satisfies the following conditions: 6 is (II) 0 < 5 < 1.5 (D II) 1 < 6 < 3, and the first and second lenses are attached to and removed from the camera body as one unit. (Claim 6)
).

[Function] As mentioned above, the 1-link lens of the present invention has "the first and second lenses are toric lenses or cylindrical lenses, the third lens is a lens symmetrical about the optical axis, You can transform the subject vertically or horizontally from different focal lengths or J.

When the condition (■) is satisfied as in the lens of claim 2, the first. Since the combination of the second lenses constitutes an afocal system, this combination can be used as a versatile converter lens.

Furthermore, if both surfaces of the third lens are made of aspherical surfaces as in the lens of claim 3 and conditions (II) and (III) are satisfied, the third lens can be used alone as a good photographic lens,
Therefore, in this case, the third lens is provided on the camera body side, and the first lens. By making the second lens integral and removable from the camera body (claim 6), it is possible to selectively perform 1 to 100 degree photography and normal photography.

Moreover, as in the camera of claim 5, the first. 2nd lens to 3rd lens
When rotated around the optical axis of the lens, the vertical and
The horizontal reduction ratio changes.

The ratio of the vertical magnification βS and the horizontal magnification βm is: 1.0×8876m<1.6 A range of is appropriate.

Conditions (II) and (III) above are conditions for correcting field curvature when the third lens is used alone.

If the lower limit of condition (II) is exceeded, the field curvature will be over-corrected, and if the upper limit is exceeded, the field curvature will be under-corrected.

If the lower limit of condition (III) is exceeded, the field curvature will be under-corrected, and if the upper limit is exceeded, the field curvature will be over-corrected.

Therefore, outside the range of 0 conditions (II) and (In), the curvature of field cannot be corrected well and aberrations deteriorate.

In addition, 1. Second. When the refractive index of the third lens material is ni+nz+n:+, these are 1.4<nl
If the conditions "n2" n3 <1.6 are satisfied, the first to third lenses can be formed of a general acrylic material with a low refractive index and low dispersion, and the processing of each lens can be facilitated.

[Example] Specific examples will be described below.

First, two examples regarding trick lenses will be given. In Example 1, the first. Both the second lenses are cylinder lenses, and in Example 2, the first lens. Both the second lenses are toric lenses.

In both Examples 1 and 2, the third lens employs an aspheric surface on the object side and image side lens surfaces.

In these Examples 1 and 2, the focal length in the meridional direction is fs, the focal length in the spherical direction is fm, and the brightness is F/No.
, the focal length of the first lens is fl, the focal length of the second lens is f2, the first . The distance between the principal points of the second lens is represented by D, the lateral magnification in the meridional direction is represented by βS, and the lateral magnification in the spherical direction is represented by βm.

Also, the i-th surface counting from the object side (including the aperture surface)
The radius of curvature of is set in the meridional direction and r1 is set in the spherical direction, A (i = 1 to 7: radius of curvature on the optical axis for an aspherical surface), the i-th and the i-th + 1st surface The surface spacing on the optical axis of is expressed as d, (i=1 to 6), and j (j=1 to 3
) represents the order of the lens from the object side.

As is well known, an aspheric surface has a coordinate in the direction of the optical axis of X, a coordinate in a direction perpendicular to the optical axis of Y, a curvature on the optical axis of C9, a conic constant, and a higher-order aspheric coefficient of A4+A6. As Aa+A1o, X
・[CY2/(1+f "Wanryo Ting"F)]+A, Y'+A
It is a curved surface obtained by rotating the curve represented by 6Y'+A, Y8+A, OY'' around the optical axis, and its shape is specified by giving a conic constant and an aspheric coefficient other than O.

Example 1 fs=35mm, fm=27mm, F/No=1
1. f, =-40,0°f2=48.5. D=
9.5, βS:βm=1:1.3z r +
−r + m d + j Material 1 −
50.00 Co 1.0 1 Acrylic 2 32.67 ω 10.03 30.0
0 00 1.5 2 Acrylic 4-115.
00 (X) 1.25 3.789 3.
789 1.2 3 Acrylic 6 4.350
4.350 2.07 00 (aperture) On the aspherical fifth lens surface, =7.0536X10-', A4=-3,2081
X10-'A6=-4.6407X 10-5. A8
=1.1400 X 10-'A+o=-1,3427
X 10-6 6=2.1470 on the 6th lens surface, A4=-2,1608X 1
0-' Example 2 fs=40.3mm, fm=26.9mm, F/N
o=11. f,=-29; 2°f2=37.8
, D=7.3, β, S:βm4:1.51
r + -r +□ d, j Material 1 -45
．． 00 38.00 2.0 1 Acrylic 2
21.40 01) 8.03 25.00
00 1.5 2 Acrylic 4 -70.9
5 33.165 1.25 3.789 3.78
9 1.2 3 Acrylic 6 4.350 4.
350 2.07 (aperture) 5=7.0536 x 10-' on the aspherical fifth lens surface, A4 =-
3,2081x 10-'A6=-4.6407X 1
0-5. A, = 1.1400 x 10-5A+o=
-1,3427X10-6 6th lens surface Ka"2.1470.A4=-2,1608X 10-
'In Example 1.2 above, the refractive index of the acrylic lens material is 1.492. In addition, the third lens is Example 1
, 2 are the same lens.

FIG. 1 shows the lens configuration and optical path of Example 1.

FIG. 2 shows the lens configuration and optical path of Example 2.

In these figures, numerals 10, 12, and 14 respectively indicate the first to third lenses, numeral 16 indicates an aperture, and numeral 18 indicates a film surface.

FIG. 3 shows an aberration diagram for Example 1, and FIG. 4 shows an aberration diagram for Example 2. SC in the diagram of spherical aberration
indicates the sine condition. Aberrations are well corrected in each example.

FIG. 5 shows one embodiment of the camera of the present invention.

Code 20 is the camera body, F is 35mm film, code 3
0 indicates a converter. The camera body 20 is the third
When a lens is installed and used only on the main body, select F/N.
o41. With f=35mm, it can be used as a regular film camera.

The converter 30 is composed of a first lens and a second lens,
It can be attached to and detached from the camera body 20.

When the converter 30 is attached to the camera body, the converter 30 can be rotated around the optical axis of the 31st lens using the rotation lever 31.

The vertical/horizontal reduction ratio is 1.3 if the trick lens of Example 1 is used, and 1.5 if the trick lens of Example 2 is used.
can be realized.

When shooting with a trick camera, for example, as shown in the right diagram of Figure 5, you can compress the left and right sides of subject O to take a smarter picture of the original subject ○, or conversely, shorten the height of the subject to take a picture. can.

In this embodiment, the first. The second lens is used as a wide converter. 1st. Although the combination of the second lenses can be configured as a teleconverter, in order to satisfactorily correct chromatic aberration, it is necessary to configure the first to third lenses with crows.

"Effects of the Invention" As described above, according to the present invention, a novel trick lens and camera can be provided.

Since these lenses and cameras are constructed as described above, it is possible to easily take good trick photographs.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the lens configuration and optical path of Example 1, FIG. 2 is a diagram showing the lens configuration and optical path of Example 2, and FIGS. 3 and 4 are aberration diagrams regarding Examples 1 and 2. FIG. 5 is a diagram for explaining one embodiment of the trick camera of the present invention. 10. , first lens, 12. , , second lens, 14. , , 3rd inertial bead surface L 2 tri L aberration distortion x left / /θθ 4F1.0

Claims (1)

[Claims] 1. First to third lenses are sequentially arranged from the object side to the image side, the first lens having negative refractive power, and the second and third lenses having positive refractive power. A trick lens characterized in that the first and second lenses are toric lenses or cylindrical lenses, the third lens is an optical axis symmetrical lens, and the focal lengths in the meridional direction and the spherical direction are different. 2. In claim 1, when the focal length of the first lens is f_1, the focal length of the second lens is f_2, and the distance between the principal points of the first and second lenses is D, these become (I) f_1+f_2≈D. A trick lens that satisfies certain conditions. 3. In claim 1 or 2, the lens surface of the third lens is an aspheric surface on both the object side and the image side, the conic coefficient K_5 of the aspheric surface of the object side lens surface, and the cone of the aspheric surface of the image side lens surface. A trick lens characterized in that the constant K_6 satisfies the following conditions: (II) 0<K_5<1.5 (III) 1<K_6<3. 4. A camera having the trick lens according to claim 1, 2 or 3. 5. The camera according to claim 4, wherein the first and second lenses are rotatable around the optical axis of the third lens. 6. In claim 4 or 5, the lens surface of the third lens of the trick lens is an aspheric surface on both the object side and the image side, and the conic coefficient K_5 of the aspheric surface of the object side lens surface and the aspheric surface of the image side lens surface are The conic constant K_6 satisfies the following conditions: (II) 0<K_5<1.5 (III) 1<K_6<3, the third lens is provided on the camera body side, and the first and second lenses
A camera characterized in that a lens can be attached to and detached from the camera body as an integral part.