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July 28, 1959

HIDEO AzuMA.

2,896,506

HIGH APERTURE WIDE-ANGLE OBJECTIVE LENs

T- 2 2 & 8

Filed June 5, 1956

X 2 34 d

INVENTOR,BY

hDEO Azuma

2 ArroyUnited States Patent-Office2,896,506

Patented July 28, 1959
2-have found to be as follows, where f is the equivalentfocal length of the total objective lens array:

2,896,506

HGHAPERTURE WP:ANGLE OBJECTIVE
Hideo Azuma, Meguroku, Tokyo, Japan, assignor to Nip

10 f>riod 1.3 f,0.07 f>dd0.03 f and0.20 f>d)0.10 f.

E.
Kogaku K.K., Tokyo, Japan, a corporation ofapan

Application June 5, 1956, Serial No. 589,554

103 Claims. (C. 88-57)

I have additionally found that the magnitude and degreeof correction obtained in the instant objectives is increasedby using materials for the positive lenses of the first,
fourth and fifth components, I, IV and V, which haveThis invention relates to a photographic objective and 5 indices of refraction for the d-line, n, n5 and ns whichmore particularly a high aperture wide-angle objective.
are larger than 1.65 but smaller than 1.80, or, mathe
An object of this invention is to obtain remarkably
matically expressed,
high intensity wide-angle optical objectives which con1.80)nd 1.65,
siderably minimize astigmatism, curvature of field,1.80)nd1.65 and20
chromatic and spherical aberration, coma and distortion.
1.80)ng> 1.65.
In wide-angle photographic objectives having an angleof field more than 60, it has hitherto been difficult to
By way of a specific embodiment of the objective of myobtain wide-angle lenses of relative apertures larger thaninvention, the data on one illustrative embodiment is:
F:2.5 and angles of field more than 60, in that when(f=1
F: 1.8Field Angle=63
the relative aperture is made larger so as to have distinct 25
vision, the coma of oblique light rays from locations away
Axial Thick Refractive Abbefrom the optical axis considerably increases, rendering it
eventually difficult to correct astigmatism, curvature offield and coma simultaneously.
The instant invention provides a photographic objective 30
having five air-spaced components, of which the first andfourth components are meniscus, single collective lenses,
the first component having its surfaces convex towards
the object side of the objective while the fourth compo
nent has its surfaces convex to the image side; the second 35
component is a meniscus dispersive component consist
ing of a positive lens cemented to a negative lens with its

Radii

ness andIndicesd=0.1000n=1.7197

Separation

r1=--0. 6024
tas -1.398
r3s --0.3943
T=--4.792
rs = -0.2439
r= -0.2562

Numbersde), 0028

d3=0.1361

n=1,6620

d=0.0250

mass 1,6206

d=0.2444
ds=0.0428

n=1.7850

r = -0.3443
surface towards the object side; the third component is
d=0, 0028'8= -1.516
a single dispersive lens with its convex surface towards
d=0.1472 ins=1.71.97
the image side; and the fifth component is a collective 40
r8= -0.4267
do=0, 0028
component consisting of a positive lens cemented to a
T0=-1.944
negative lens, the convex surface of the fifth component
do=0.0889 n=1,.6910
r=-2.903being towards the object side. With individual magni
dis0.0333 n=1,7850
tudes of the components observing the hereinafter identi
r1= --5.855
fied magnitudes, I have obtained the high aperture, wide 45
angle, objective of the foregoing type which has exceed
Petzvah's sum: 0.222.
ingly small values for the aberrations for improved perI
have
noted
that
the adjacent surfaces of the positiveformance.
andnegativelensesof the second component II, need
A clearer conception of the scope and purpose of thisnot
becemented
togetherbut that a narrow air space50
invention may be obtained from the following descrip
can be left between them. In such case, the radius oftion, taken in connection with the attached drawing ineach such adjacent face being denoted by r and r" needwhich the sole figure shows an illustrative embodiment ofnotbe absolutely identical but may differ slightly frommy invention, the components having increasing reference
eachother and the air space between them denoted bycharacters, I, II . . . V, in the direction from the object 55 d. Thenwithout changing the subscripts for the lensside to the image side. The radii of curvature r of thethickness,separation
radii for the lens components
successive optical surfaces, the axial distances d of the immediately followingand
the air space d towards the image
individual lens thicknesses and between-the-lens spacings,
side, the above said requirements are fully satisfied.
and the refractive indices in for the d-line of the materials
What I claim is:of the individual lenses have increasing subscripts in the1. A high aperture, wide angle photographic objective60
same direction to identify the particular magnitude
comprising
five components spaced from each other ofprecisely.
which
thefirstcomponent I is a single meniscus collec
Coma of oblique rays, I have found, is corrected bytivelenswith
its
convex surface toward the object sidecomparatively enlarging the radii of curvature, rs and re.
of the objective, the second component II is a meniscusof the two dispersive lenses, II and III, between which
component consisting of a positive lens
the diaphragm is positioned and by making the radius rio 65 dispersive
cementedtoa negative lens, the convex surface of theof the front surface of the fifth component V divisionallysecond component being towards the object side, thebear the converging power of the rear surfaces, r and rg,
third component III is a single meniscus dispersive lensof the third and fourth components, III and IV. Astig
with its convex surface of radius r towards the image
matism and curvature of field is corrected by the effectitionedof the relation of the axial thickness, ds and ds, of the 70 side of the objective, the diaphra bein
third and fourth components, III and IV.
between the surfaces of radirs and re of the second andThe requirements, in accordance with my invention, I third components respectively, the fourth component IV isww.

..

--

2,896,506ya

3
a meniscus single collective lens with its convex surfaceof radius r towards the image side, and the fifth com

ponent and of the positive lens of the fifth component
lies between 1.65 and 1.80.
3. A high aperture, wide angle photographic objective
highly corrected for astigmatism, curvature of field, comaand distortion, of which the magnitudes are as follows:ponent V is a collective component consisting of a positive lens cemented to a negative lens, the convex surfaceof radius r of the fifth component being towards theobject side, the radii rs, re, r, rig and rio, and the axial
thicknesses d and d of the third and fourth components
meeting the following requirements in terms of theequivalent focal length f of the total objective array:0.30 f>rs>0.17 f,

If-ti

O Lens Component

0.30 f>|rd0.17 f,
0.43 f>ird0.28 f,
0.53 f>|rg>0.36 f
10 f>riod 1.3 f,
0.07 feded 0.03 f, and0.20 feded 0.10 f,

4

and the refractive index of each the first and fourthcom

I.---------------15
II.---------------and the refractive index of each the first and fourth com

E: 1.8Radiusr1=--0. 6024
r=-|-1.398
ta=--0.3943
r= -4.792
rs = -0.2439

2ast 68°

Axial Thick- Refractive Abbe
ness andIndex Number

Separation

d=0.1000-1.797d=0.0028
d=0.1361 mg=1,6620
d45=0.0250 73= i. 6206
dis=0.2444
d=0.0428 4- 850=50.2

a = 57.7t3=38.0

ponent and of the positive lens of the fifth component
r= -0.2562
lies between 1.65 and 1.80.
=25.9
2. A high aperture, wide angle photographic objective 20 III--------------- r= -0.3443
d=00028
comprising five components spaced from each other of-1516
which the first component I is a single meniscus collec IV--------------- r=
diss0.1472 iss-1.797 ass=50.2
g=-0, 4267
tive dens with its convex surface toward the object side
d=0.0028
r10 = -1.944
of the objective, the second component II is a meniscus
dios=0.0889 mis-i. 6910 ass=54.
dispersive component consisting of a positive lens spaced 25
rl = -2.903
a slight distance da from a negative lens, the adjacent V---------------- r12 =--5.855 d=0.0333 27 = 7850 =25.9
surfaces having substantially the same radius of curvature,
the convex surface of the second component being
towards the object side, the third component III is a 30 where rsubscript is the radius of curvature of the refractive
dsubscript the axial distance of the lens thickness
single meniscus dispersive lens with its convex surface of . Surface,respectively spacing, insubscript the index of refraction on
radius r towards the image side of the objective, thethe d-line, and vsubscript the Abbe number, with all sub
diaphragm being positioned between the surfaces of radii
scripts increasing in magnitude in the direction from thers and r of the second and third components respectively,
the fourth component IV is a meniscus single collective 35 object to the image side of the objective for successive
component with its convex surface of radius rig towards occurrences thereof.
the image side, and the fifth component V is a collective
References Cited in the file of this patentcomponent consisting of a positive lens cemented to a
UNITED STATES PATENTS
negative lens, the convex surface of radius r of the fifthcomponent being towards the object side, the radii rs 40 2,389,016 Wynne --------------- Nov. 13, 1945
rs, r, rs and ro, and the axial thicknesses de and ds of2,720,139
Tronnier --------------- Oct. 11, 1955
the third and fourth components meeting the following
2,733,636 Tronnier --------------- Feb. 7, 1956
requirements in terms of the equivalent focal length f of2,735,339
Doi ------------------ Feb. 21, 1956
the total objective array:
FOREIGN PATENTS
45
0.30 f>rs>0.17 f,
796,086
France---------------- Jan. 17, 1936
0.30 f>|rsd0.17 f,

0.43 for>0.28 f,
0.53 f>red 0.36 f,

10 f>riod 1.3 f,
0.07 feded 0.03 f, and0.20 f>dd0.10 f,

50