U.S. patent application number 14/141011 was filed with the patent office on 2014-07-03 for zoom lens and camera device.
This patent application is currently assigned to TAMRON CO., LTD.. The applicant listed for this patent is TAMRON CO., LTD.. Invention is credited to Yoshito Iwasawa, Jun Takahashi.
Application Number | 20140184884 14/141011 |
Document ID | / |
Family ID | 50993025 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140184884 |
Kind Code |
A1 |
Iwasawa; Yoshito ; et
al. |
July 3, 2014 |
ZOOM LENS AND CAMERA DEVICE
Abstract
The zoom lens comprises the foremost or first lens group of
positive refractive power located the closest to an object, the
succeeding second lens group of negative refractive power, and the
third lens group of positive refractive power, all arranged in this
order, and if any, the rearmost lens group(s) closer to the imaging
plane than the third lens group, all or part of the lens group(s)
of negative refractive power behind the third lens group being
moved in directions normal to the optical axis to serve as an
anti-vibration lens for shifting an image. The zoom lens meets
requirements as defined in the formula regarding a displacement of
the first lens group, a focal length of the zoom lens at the
wide-angle end, a focal length of the zoom lens at the telephoto
end, and a focal length of the first lens group.
Inventors: |
Iwasawa; Yoshito; (Tokyo,
JP) ; Takahashi; Jun; (Ashigarakami-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAMRON CO., LTD. |
Saitama-shi |
|
JP |
|
|
Assignee: |
TAMRON CO., LTD.
Saitama-shi
JP
|
Family ID: |
50993025 |
Appl. No.: |
14/141011 |
Filed: |
December 26, 2013 |
Current U.S.
Class: |
348/345 ;
359/683; 359/690 |
Current CPC
Class: |
G02B 5/005 20130101;
G02B 27/0025 20130101; G02B 15/173 20130101; G02B 27/646
20130101 |
Class at
Publication: |
348/345 ;
359/690; 359/683 |
International
Class: |
G02B 13/00 20060101
G02B013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2012 |
JP |
2012-286012 |
Claims
1. A zoom lens comprising three or more groups of lens pieces, the
foremost or first lens group of positive refractive power located
the closest to an object, the succeeding second lens group of
negative refractive power, and the third lens group of positive
refractive power, all arranged in this order, and if any, the
rearmost lens group(s) closer to the imaging plane than the third
lens group, all or part of the lens group(s) of negative refractive
power behind the third lens group being moved in directions normal
to the optical axis to serve as an anti-vibration lens for shifting
an image; and the zoom lens meeting the requirements as defined in
the following formula: 0.11.ltoreq.X1/fT.ltoreq.0.28 (1)
0.5.ltoreq.f1/ {square root over ((fw.times.fT))}.ltoreq.1.3 (2)
0.20.ltoreq.f3/ {square root over ((fw.times.fT))}.ltoreq.0.45 (3)
where X1 is a displacement of the first lens group when the zoom
lens is extended from the wide-angle end to the telephoto end to
vary optical power, fw is a focal length of the zoom lens at the
wide-angle end, fT is a focal length of the zoom lens at the
telephoto end, f1 is a focal length of the first lens group, and f3
is a focal length of the third lens group.
2. A zoom lens comprising five or more groups of lens pieces, the
foremost or first lens group of positive refractive power located
the closest to an object, the succeeding second lens group of
negative refractive power, the third lens group of positive
refractive power, the fourth lens group, and the fifth lens group,
all arranged in this order, all or part of the lens group(s) of
negative refractive power behind the third lens group being moved
in directions normal to the optical axis to serve as an
anti-vibration lens for shifting an image; and the zoom lens
meeting the requirements as defined in the following formula:
0.11.ltoreq.X1/fT.ltoreq.0.28 (1) 0.5.ltoreq.f1/ {square root over
((fw.times.fT))}.ltoreq.1.3 (2) where X1 is a displacement of the
first lens group when the zoom lens is extended from the wide-angle
end to the telephoto end to vary optical power, fw is a focal
length of the zoom lens at the wide-angle end, fT is a focal length
of the zoom lens at the telephoto end, and f1 is a focal length of
the first lens group.
3. The zoom lens according to claim 2, wherein the zoom lens meets
the requirements as defined about the third lens group in the
following formula (3): 0.20.ltoreq.f3/ {square root over
((fw.times.fT))}.ltoreq.0.45 (3) where f3 is a focal length of the
third lens group.
4. The zoom lens according to claim 1, wherein the zoom lens
comprises a lens group(s) of positive refractive power and/or a
component lens piece(s) of positive refractive power located closer
to the object than all or part of the lens group(s) of negative
refractive power moved to serve as an anti-vibration lens for
shifting an image.
5. The zoom lens according to claim 1, wherein the zoom lens has
one or more lens pieces of positive and negative refractive power
in all or part of the lens group(s) of negative refractive power
moved to serve as an anti-vibration lens for shifting an image.
6. The zoom lens according to claim 1, wherein part or all of the
lens group(s) moved to serve as an anti-vibration lens for shifting
an image meet the requirements as defined in the following formula
(4): -2.8.ltoreq.(1-.beta.a).times..beta.b.ltoreq.-1.0 (4) where
.beta.a is an optical power of the lens group(s) movable in
directions normal to the optical axis when the zoom lens is taking
a posture of the telephoto end, and .beta.b is a synthetic optical
power of a lens group(s) closer to the imaging plane than the lens
group(s) movable in directions normal to the optical axis.
7. The zoom lens according to claim 1, wherein the zoom lens meets
the requirements as defined in the following formula (5):
0.60.ltoreq.Lt/fT.ltoreq.0.75 (5) where Lt is an entire length of
the optical system of the zoom lens at the telephoto end, and fT is
a focal length of the zoom lens at the telephoto end.
8. The zoom lens according to claim 1, wherein the zoom lens has
two or more lens groups located behind the third lens group and
moved to vary optical power.
9. A camera device comprising image sensors disposed on or behind
the imaging plane of the zoom lenses according to claim 1, for
converting an optical image created by the zoom lens into
electrical signals.
10. The zoom lens according to claim 2, wherein the zoom lens
comprises a lens group(s) of positive refractive power and/or a
component lens piece(s) of positive refractive power located closer
to the object than all or part of the lens group(s) of negative
refractive power moved to serve as an anti-vibration lens for
shifting an image.
11. The zoom lens according to claim 2, wherein the zoom lens has
one or more lens pieces of positive and negative refractive power
in all or part of the lens group(s) of negative refractive power
moved to serve as an anti-vibration lens for shifting an image.
12. The zoom lens according to claim 2, wherein part or all of the
lens group(s) moved to serve as an anti-vibration lens for shifting
an image meet the requirements as defined in the following formula
(4): -2.8.ltoreq.(1-.beta.a).times..beta.b.ltoreq.-1.0 (4) where
.beta.a is an optical power of the lens group(s) movable in
directions normal to the optical axis when the zoom lens is taking
a posture of the telephoto end, and .beta.b is a synthetic optical
power of a lens group(s) closer to the imaging plane than the lens
group(s) movable in directions normal to the optical axis.
13. The zoom lens according to claim 2, wherein the zoom lens meets
the requirements as defined in the following formula (5):
0.60.ltoreq.Lt/fT.ltoreq.0.75 (5) where Lt is an entire length of
the optical system of the zoom lens at the telephoto end, and fT is
a focal length of the zoom lens at the telephoto end.
14. The zoom lens according to claim 2, wherein the zoom lens has
two or more lens groups located behind the third lens group and
moved to vary optical power.
15. A camera device comprising image sensors disposed on or behind
the imaging plane of the zoom lenses according to claim 2, for
converting an optical image created by the zoom lens into
electrical signals.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to zoom lenses,
interchangeable lens units incorporating the zoom lenses, and
camera devices used with the same. More particularly, the present
invention relates to high variable power compact zoom lenses
suitable to camera optical systems for digitized signal
input/output devices such as digital still cameras, digital video
cameras, and the like, interchangeable lens units incorporating the
zoom lenses, and camera devices used with the same.
BACKGROUND ART
[0002] Recently, camera devices, such as digital still cameras,
incorporating solid-state image sensors have been popular. This
tendency of the market demand has been followed by the performance
improvement and downsizing of optical systems, and more compact
camera systems have rapidly become commercially available. Optical
systems in such camera systems are of higher-performance oriented
and increasingly downsizing oriented design to meet the market
demands for zoom lens optical systems with a shortened entire
length and for lens barrels with a reduced diameter. Especially, it
is highly desired that optical systems, such as tele-photographing
zoom lenses, having an increased focal length should be of more
enhanced performance and reduced dimensions.
[0003] One prior art highly variable power compact zoom lens, which
satisfies the demands of higher-performance and reduced dimensions,
comprises the foremost or first lens group G1 of positive
refractive power located the closest to an object, the succeeding
or second lens group G2 of negative refractive power, the third
lens group G3 of positive refractive power, and the fourth lens
group L4 of positive refractive power located the closest to the
imaging plane, and such a prior art zoom lens meets the
requirements as defined in the following formula:
12<Lt/(Ft/Fw)<15
where Lt is an entire length of the optical system (a distance from
the front surface of the front lens piece the closest to the object
to the imaging plane) when the zoom lens is taking a posture of the
telephoto end, Ft is a focal length of the optical system as a
whole when the zoom lens is taking a posture of the telephoto end,
and Fw is a focal length of the optical system as a whole when the
zoom lens is taking a posture of the wide-angle end (e.g., see
Patent Document 1 listed below).
LIST OF DOCUMENTS OF THE RELATED ART
Patent Document 1
[0004] Official Gazette of JP-A-2011-248220
[0005] The prior art highly variable power compact zoom lens
mentioned above has its lens group of negative refractive power
deviated/displaced in directions normal to the optical axis to
serve as an anti-vibration lens, which is intended to downsize the
lens barrel by downsizing the anti-vibration lens in diametral
dimension. Due to a great displacement of the first lens group,
however, the cam mechanism in the lens barrel is unavoidably so
complicated as recognized in multi-stage cam design, and the
resultant zoom lens is still unsatisfactory in that the lens barrel
is not sufficiently downsized.
[0006] Allowing for the aforementioned disadvantages in the prior
art highly variable power compact zoom lens, the present invention
is directed to providing an improved zoom lens that attains
high-performance imaging suitable to changeable lenses and/or
camera devices incorporating solid-state image sensors, such as
digital still cameras, digital video cameras, and the like, of
which pixels are much more minute than those of photographing film,
and providing an improved camera device used with such a zoom
lens.
[0007] The present invention is also directed to providing an
improved zoom lens in which a displacement of a lens group(s) moved
to vary optical power is reduced so as to reduce a diametral
dimension of the lens barrel and simplify a barrel structure, and
also, in which a lens group(s) of negative refractive power serve
as an anti-vibration lens to attain the same object, namely to
reduce the diametral dimension of the lens barrel.
SUMMARY OF THE INVENTION
[0008] A first zoom lens in accordance with the present invention
comprises three or more groups of lens pieces, the foremost or
first lens group of positive refractive power located the closest
to an object, the succeeding second lens group of negative
refractive power, and the third lens group of positive refractive
power, all arranged in this order, and if any, the rearmost lens
group(s) closer to the imaging plane than the third lens group, all
or part of the lens group(s) of negative refractive power behind
the third lens group being moved in directions normal to the
optical axis to serve as an anti-vibration lens for shifting an
image; and the zoom lens meets the requirements as defined in the
following formula:
0.11.ltoreq.X1/fT.ltoreq.0.28 (1)
0.5.ltoreq.f1/ {square root over ((fw.times.fT))}.ltoreq.1.3
(2)
0.20.ltoreq.f3/ {square root over ((fw.times.fT))}.ltoreq.0.45
(3)
where X1 is a displacement of the first lens group when the zoom
lens is extended from the wide-angle end to the telephoto end to
vary optical power, fw is a focal length of the zoom lens at the
wide-angle end, fT is a focal length of the zoom lens at the
telephoto end, f1 is a focal length of the first lens group, and f3
is a focal length of the third lens group.
[0009] A second zoom lens in accordance with the present invention
comprises five or more groups of lens pieces, the foremost or first
lens group of positive refractive power located the closest to an
object, the succeeding second lens group of negative refractive
power, the third lens group of positive refractive power, the
fourth lens group, and the fifth lens group, all arranged in this
order, all or part of the lens group(s) of negative refractive
power behind the third lens group being moved in directions normal
to the optical axis to serve as an anti-vibration lens for shifting
an image; and the zoom lens meets the requirements as defined in
the following formula:
0.11.ltoreq.X1/fT.ltoreq.0.28 (1)
0.5.ltoreq.f1/ {square root over ((fw.times.fT))}.ltoreq.1.3
(2)
where X1 is a displacement of the first lens group when the zoom
lens is extended from the wide-angle end to the telephoto end to
vary optical power, fw is a focal length of the zoom lens at the
wide-angle end, fT is a focal length of the zoom lens at the
telephoto end, and f1 is a focal length of the first lens
group.
[0010] A camera device in accordance with the present invention
comprises image sensors disposed on or behind the imaging plane of
any of the aforementioned zoom lenses according to the present
invention, for converting an optical image created by the zoom lens
into electrical signals.
[0011] In accordance with the present invention, the zoom lens
attains high-performance imaging suitable to attachment lenses
and/or camera devices incorporating solid-state image sensors, such
as digital still cameras, digital video cameras, and the like, of
which pixels are much more minute than those of photographing film,
and the camera device is suitably used with such a zoom lens.
[0012] Moreover, in the zoom lens according to the present
invention, a displacement of a lens group(s) moved to vary optical
power is reduced so as to reduce a diametral dimension of the lens
barrel and simplify a barrel structure, and also, the lens group(s)
of negative refractive power serve as an anti-vibration lens to
attain the same object, namely to reduce the diametral dimension of
the lens barrel.
[0013] Furthermore, the zoom lens according to the present
invention, which comprises at least three groups of lens pieces,
namely, the foremost or first lens group of positive refractive
power positioned the closest to an object, the second lens group of
negative refractive power, and the third lens group of positive
refractive power, and if any, the rearmost lens group(s) behind the
third lens group, is capable of varying three or more dimensional
components or distances between the lens groups adjacent to each
other during varying its optical power so as to obtain an enhanced
freedom to compensate for aberrations.
[0014] In a first aspect of the present invention, the first zoom
lens meets the requirements as defined about the third lens group
in the following formula (3):
0.20.ltoreq.f3/ {square root over ((fw.times.fT))}.ltoreq.0.45
(3)
where f3 is a focal length of the third lens group.
[0015] In a second aspect of the present invention, the first or
second zoom lens of the present invention comprises a lens group(s)
of positive refractive power and/or a component lens piece(s) of
positive refractive power located closer to the object than all or
part of the lens group(s) of negative refractive power moved to
serve as an anti-vibration lens for shifting an image.
[0016] In a third aspect of the present invention, the first or
second zoom lens of the present invention has one or more lens
pieces of positive and negative refractive power in all or part of
the lens group(s) of negative refractive power moved to serve as an
anti-vibration lens for shifting an image.
[0017] In a fourth aspect of the present invention, the first or
second zoom lens of the present invention is designed so that part
or all of the lens group(s) moved to serve as an anti-vibration
lens for shifting an image meet the requirements as defined in the
following formula (4):
-2.8.ltoreq.(1-.beta.a).times..beta.b.ltoreq.-1.0 (4)
where .beta.a is an optical power of the lens group(s) movable in
directions normal to the optical axis when the zoom lens is taking
a posture of the telephoto end, and .beta.b is a synthetic optical
power of a lens group(s) closer to the imaging plane than the lens
group(s) movable in directions normal to the optical axis.
[0018] In a fifth aspect of the present invention, the first or
second zoom lens of the present invention is designed to meet the
requirements as defined in the following formula (5):
0.60.ltoreq.Lt/fT.ltoreq.0.75 (5)
where Lt is an entire length of the optical system of the zoom lens
at the telephoto end, and fT is a focal length of the zoom lens at
the telephoto end.
[0019] In a sixth aspect of the present invention, the first or
second zoom lens of the present invention comprises two or more
lens groups located behind the third lens group and moved to vary
optical power.
[0020] The formula (1) defines the requirements for a displacement
of the first lens group in the zoom lens during extending from the
wide-angle end to the telephoto end.
[0021] When an actual value of X1/fT exceeds the upper limit
defined in the formula (1), the displacement of the first lens
group in the resultant zoom lens is increased, and this unavoidably
brings about a complicated barrel design as recognized in a
multi-stage lens barrel arrangement, which in turn hinders
downsizing the lens barrel.
[0022] When an actual value of X1/fT is smaller than the lower
limit defined in the formula (1), the resultant zoom lens has its
optical system varied not so much in entire length between the
telephoto end and the wide-angle end, but the entire length of the
optical system at the wide-angle end is excessively great, which in
turn brings about an increase in a diameter of the first lens group
located the closest to the object as well as an increase of an
entire longitudinal dimension of the lens barrel.
[0023] To obtain more significant effects, the formula (1) may
desirably be modified as follows:
0.11.ltoreq.X1/fT.ltoreq.0.22 (1')
[0024] To obtain much more significant effects, the formula (1) may
desirably be modified as follows:
0.11.ltoreq.X1/fT.ltoreq.0.18 (1'')
[0025] The formula (2) defines the requirements for a focal
distance of the first lens group in the zoom lens.
[0026] When an actual value of f1/ (fwfT) is smaller than the lower
limit defined in the formula (2) to intensify the positive
refractive power of the first lens group, the resultant zoom lens
taking a posture of the telephoto end develops chromatic aberration
so great as to cause a difficulty in compensating for it.
[0027] When an actual value of f1/ (fwfT) exceeds the upper limit
defined in the formula (1) to weaken the positive refractive power
of the first lens group, a flux of beams incident upon the second
lens group is not sufficiently converged, and this unavoidably
brings about an increase in dimensions of the second lens group and
an increase in a displacement of the first lens group, which in
turn leads to an increase in dimensions of the lens barrel as a
whole.
[0028] To obtain more significant effects, the formula (2) may
desirably be modified as follows:
0.6.ltoreq.f1/ {square root over ((fw.times.fT))}.ltoreq.1.2
(2')
[0029] To obtain much more significant effects, the formula (2) may
desirably be modified as follows:
0.7.ltoreq.f1/ {square root over ((fw.times.fT))}.ltoreq.1.1
(2'')
[0030] The formula (3) defines the requirements for a focal
distance of the third lens group in the zoom lens.
[0031] When an actual value of f3/ (fwfT) is smaller than the lower
limit defined in the formula (3) to intensify the positive
refractive power of the first lens group, the resultant zoom lens
taking a posture of the telephoto end develops spherical aberration
so great as to cause a difficulty in compensating for it.
[0032] When an actual value of f3/ (fwfT) exceeds the upper limit
defined in the formula (3) to weaken the positive refractive power
of the first lens group, a flux of beams incident upon the lens
group(s) or an anti-vibration lens behind the third lens group is
not sufficiently converged, and this unavoidably brings about an
increase in dimensions of the anti-vibration lens and an increase
in dimensions of an anti-vibration lens unit, which in turn leads
to an increase in dimensions of the lens barrel as a whole.
[0033] To obtain more significant effects, the formula (3) may
desirably be modified as follows:
0.20.ltoreq.f3/ {square root over ((fw.times.fT))}.ltoreq.0.40
(3')
[0034] To obtain much more significant effects, the formula (3) may
desirably be modified as follows:
0.20.ltoreq.f3/ {square root over ((fw.times.fT))}.ltoreq.0.35
(3'')
[0035] The formula (4) defines the requirements for a rate of a
displacement of the lens group(s) movable in directions normal to
the optical axis to an amount by which an image is shifted.
[0036] When an actual value of (1-.beta.a).beta.b is smaller than
the lower limit defined in the formula (4), the resultant zoom lens
adversely permits an image to shift greatly even with a minor
displacement of the lens group(s) movable in directions normal to
the optical axis or the anti-vibration lens, and thus,
high-precision control of the anti-vibration lens is required.
[0037] When an actual value of (1-.beta.a).beta.b exceeds the upper
limit defined in the formula (4), the resultant zoom lens has to
have the anti-vibration lens displaced more in directions normal to
the optical axis to shift the image by a predetermined amount, and
for that purpose, a larger lens actuator system for driving the
anti-vibration lens is needed, which hinders downsizing the lens
barrel.
[0038] The formula (5) defines the requirements for dimensions of
the optical system of the zoom lens at the telephoto end.
[0039] Fulfilling the conditions defined in the formula (5) enables
the zoom lens especially to have the optical system considerably
reduced in entire length when it is taking a posture of the
telephoto end and have the optical system enhanced in imaging
performance.
[0040] When an actual value of Lt/fT is smaller than the lower
limit defined in the formula (5), the resultant zoom lens has its
optical system excessively reduced in entire length when it is
taking a posture of the telephoto end, and the zoom lens encounters
a difficulty in ensuring the desired optical performance when it is
taking a posture of the wide-angle end.
[0041] Reversely, when an actual value of Lt/fT exceeds the upper
limit defined in the formula (5), the resultant zoom lens has its
optical system increased in entire length when it is taking a
posture of the telephoto end, which hinders downsizing the lens
barrel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a vertical sectional view showing a lens
arrangement in a first embodiment of a zoom lens according to the
present invention when the zoom lens is taking a posture of the
wide-angle end,
[0043] FIG. 2 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the first embodiment of the
zoom lens when the zoom lens taking a posture of the wide-angle end
is in focus on the point at infinity, the graphs of spherical
aberration showing a rate of a stop setting F-number to the full
diaphragm stop setting F-number on the vertical axis and a degree
of defocusing on the horizontal axis for the d-line (wavelength
587.6 nm) expressed by solid line, the c-line (wavelength 656.3 nm)
by broken line, and the g-line (wavelength 435.8 nm) by alternate
long and short dash line, the graphs of astigmatism showing an
image height on the vertical axis and a degree of defocusing on the
horizontal axis for a sagittal imaging plane expressed by solid
line and a meridional imaging plane by broken line, and the graphs
of distortion aberration show an image height on the vertical axis
and a degree of distortion in percentage,
[0044] FIG. 3 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the first embodiment of the
zoom lens when the zoom lens taking a posture of the intermediate
zooming range is in focus on the point at infinity,
[0045] FIG. 4 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the first embodiment of the
zoom lens when the zoom lens taking a posture of the telephoto end
is in focus on the point at infinity,
[0046] FIG. 5 is a vertical sectional view showing a lens
arrangement in a second embodiment of the zoom lens according to
the present invention when the zoom lens is taking a posture of the
wide-angle end,
[0047] FIG. 6 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the second embodiment of the
zoom lens when the zoom lens taking a posture of the wide-angle end
is in focus on the point at infinity,
[0048] FIG. 7 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the second embodiment of the
zoom lens when the zoom lens taking a posture of the intermediate
zooming range is in focus on the point at infinity,
[0049] FIG. 8 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the second embodiment of the
zoom lens when the zoom lens taking a posture of the telephoto end
is in focus on the point at infinity,
[0050] FIG. 9 is a vertical sectional view showing a third
embodiment of the zoom lens according to the present invention when
the zoom lens is taking a posture of the wide-angle end,
[0051] FIG. 10 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the third embodiment of the
zoom lens when the zoom lens taking a posture of the wide-angle end
is in focus on the point at infinity,
[0052] FIG. 11 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the third embodiment of the
zoom lens when the zoom lens taking a posture of the intermediate
zooming range is in focus on the point at infinity,
[0053] FIG. 12 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the third embodiment of the
zoom lens when the zoom lens taking a posture of the telephoto end
is in focus on the point at infinity,
[0054] FIG. 13 is a vertical sectional view showing a fourth
embodiment of the zoom lens according to the present invention when
the zoom lens is taking a posture of the wide-angle end,
[0055] FIG. 14 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the fourth embodiment of the
zoom lens when the zoom lens taking a posture of the wide-angle end
is in focus on the point at infinity,
[0056] FIG. 15 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the fourth embodiment of the
zoom lens when the zoom lens taking a posture of the intermediate
zooming range is in focus on the point at infinity,
[0057] FIG. 16 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the fourth embodiment of the
zoom lens when the zoom lens taking a posture of the telephoto end
is in focus on the point at infinity,
[0058] FIG. 17 is a vertical sectional view showing a fifth
embodiment of the zoom lens according to the present invention when
the zoom lens is taking a posture of the wide-angle end,
[0059] FIG. 18 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the fifth embodiment of the
zoom lens when the zoom lens taking a posture of the wide-angle end
is in focus on the point at infinity,
[0060] FIG. 19 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the fifth embodiment of the
zoom lens when the zoom lens taking a posture of the intermediate
zooming range is in focus on the point at infinity, and
[0061] FIG. 20 depicts graphs of spherical aberration, astigmatism,
and distortion aberration developed in the fifth embodiment of the
zoom lens when the zoom lens taking a posture of the telephoto end
is in focus on the point at infinity.
BEST MODE OF THE INVENTION
Embodiment 1
[0062] FIG. 1 is a vertical sectional view showing a lens
arrangement of a first embodiment of a zoom lens according to the
present invention. The first embodiment of the zoom lens comprises
the foremost or first lens group G1 of positive refractive power
located the closest to an object, the succeeding second lens group
G2 of negative refractive power, the third lens group G3 of
positive refractive power, the fourth lens group G4 of positive
refractive power, the fifth lens group G5 of negative refractive
power, and the rearmost or sixth lens group G6 of negative
refractive power arranged in this order.
[0063] The first lens group G1 comprises a duplet of a meniscus
lens piece L1 of negative refractive power with its convex surface
oriented to the object and a lens piece L2 of positive refractive
power cemented with the meniscus lens piece L1, and a lens piece L3
of positive refractive power, all the lens pieces being arranged in
this order from the closest to the object in the foremost position
to the farthest in the rearmost position.
[0064] The second lens group G2 comprises a duplet of a lens piece
L4 of negative refractive power with its concave surface oriented
toward the object and a meniscus lens piece L5 of positive
refractive power cemented with the lens piece L4, and a meniscus
lens piece L6 of negative refractive power with its concave surface
oriented toward the object.
[0065] The third lens group G3 comprises a biconvex lens piece L7,
a biconvex lens piece L8, a duplet of a lens piece L9 of positive
refractive power with its convex surface oriented toward the object
and a lens piece L10 of negative refractive power cemented with the
lens piece L9, and another duplet of a biconcave lens piece L11 and
a meniscus lens piece L12 of positive refractive power with its
convex surface oriented toward the object, all the lens pieces
arranged in this order from the closest to the object in the
foremost position to the farthest in the rearmost position.
[0066] The fourth lens group G4 comprises a biconvex lens piece
L13, and a duplet of a lens piece L14 of positive refractive power
with its convex surface oriented toward the object and a lens piece
L15 of positive refractive power cemented with the lens piece L14,
all the lens pieces being arranged in this order from the closest
to the object in the foremost position to the farthest from the
object in the rearmost position.
[0067] The fifth lens group G5 comprises a duplet of a biconvex
lens piece L16 positioned closer to the object and a biconcave lens
piece L17 cemented with the biconvex lens piece L16.
[0068] The sixth lens group G6 comprises a meniscus lens piece L18
of negative refractive power with its concave surface oriented
toward the object.
[0069] During varying optical power from the wide-angle and to the
telephoto end, the first embodiment of the zoom lens has its first
lens group moved toward the object, its second lens group held in a
fixed position, its third lens group moved on a trajectory that
draws an are toward the imaging plane relative to the second lens
group, its fourth lens group moved on a trajectory that draws an
arc toward the imaging plane relative to the third lens group, its
fifth lens group moved toward the object, and its sixth lens group
moved in the same manner as the fourth lens group.
[0070] Focusing on an object at the near point is carried out by
moving the fifth lens group toward the imaging plane. For that
purpose, the duplet of the lens pieces L11 and L12 cemented
together is moved in vertical directions normal to the optical axis
so as to correct fuzziness of an image during photographing.
[0071] Optical data of the lens pieces in the first embodiment of
the zoom lens are provided in Table 1. Surface number NS designates
the n-th lens surface of the optical system where all the component
lens pieces are arranged in order on the
closest-to-the-object-first basis, R is a radius of curvature of
the n-th lens surface, D is a distance along the optical axis
between a pair of the adjacent lens surfaces, Nd is a refractive
index for the d-line (wavelength .lamda.=587.6 nm), and .nu.d is an
Abbe number for the d-line (wavelength .lamda.=587.6 nm).
[0072] An aperture stop or an aperture diaphragm is denoted by STOP
suffixed to the surface number.
TABLE-US-00001 TABLE 1 NS R D Nd .nu.d 1 486.4782 1.4500 1.83400
37.34 2 83.3399 0.0100 1.56732 42.84 3 83.3399 5.5100 1.49700 81.61
4 -172.8214 0.1500 5 63.2093 5.2914 1.48749 70.44 6 -895.6302 D(6)
7 0.0000 1.8876 8 -96.2544 0.7500 1.76524 50.37 9 18.4045 0.0100
1.56732 42.84 10 18.4045 3.0631 1.80518 25.46 11 70.9807 2.5194 12
-41.5515 0.7000 1.80420 46.50 13 -10114.4818 D(13) 14 39.2470
4.1119 1.49700 81.61 15 -41.3613 0.1000 16 40.1380 2.6375 1.48749
70.44 17 -1692.6300 0.1000 18 43.0535 3.8276 1.48749 70.44 19
-29.6342 0.0100 1.56732 42.84 20 -29.6342 0.7000 1.90739 33.25 21
119.5406 6.7000 22 -1390.5046 0.6000 1.77791 44.07 23 18.4637
0.0100 1.56732 42.84 24 18.4637 2.3536 1.90366 31.31 25 48.8224
2.3000 26 STOP 0.0000 D(26) 27 52.7369 2.8298 1.56732 42.84 28
-27.8361 0.1000 29 26.5392 3.2246 1.54356 46.62 30 -23.1396 0.0100
1.56732 42.84 31 -23.1396 0.6000 1.90366 31.31 32 104.0723 D(32) 33
54.2263 1.4342 1.80518 25.46 34 -61.6536 0.0100 1.56732 42.84 35
-61.6536 0.5600 1.74161 49.80 36 16.9498 D(36) 37 -24.4610 0.9300
1.48749 70.44 38 -87.3035 0.0000 39 0.0000 D(39) 40 0.0000 2.8000
1.51680 64.20 41 0.0000 1.0000
[0073] Distances between the adjacent lens surfaces in several
pairs in the first embodiment of the zoom lens are given in Table 2
below as well as varied values of the focal distance f, the
F-number Fno, and the field angle .omega. for each of the zooming
settings at the wide-angle end (f=68.7634), at the intermediate
zooming range (f=149.5669), and at the telephoto end (f=291.2580),
respectively.
TABLE-US-00002 TABLE 2 f 68.7634 149.5669 291.2580 Fno 4.62776
5.18280 6.80830 .omega. 6.8004 3.13810 1.61270 D(6) 18.4552 49.5086
57.3552 D(13) 24.5140 18.2970 1.5000 D(26) 4.3452 4.2773 7.7592
D(32) 5.4806 1.4000 2.7630 D(36) 11.0774 15.1581 13.7950 D(39)
19.7269 26.0118 39.3269
[0074] Distances between the adjacent lens surfaces in several
pairs in the first embodiment of the zoom lens during focusing on
an object at the near point for zooming settings at the wide-angle
end (f=68.7634), at the intermediate zooming range (f=149.5669),
and at the telephoto end (f=291.2580), respectively, are given in
Table 3 below as well as varied values of the focal length f upon
focusing on an object at infinite distance away and the distance
D(0) from the front surface of the first lens piece to the
object.
TABLE-US-00003 TABLE 3 f 68.7634 149.5669 291.2580 D(0) 1058.11
1027.06 1019.21 D(32) 6.6285 4.8033 12.0080 D(36) 9.9260 11.7548
4.5501
Embodiment 2
[0075] FIG. 5 is a vertical sectional view showing a lens
arrangement of a second embodiment of the zoom lens according to
the present invention. The second embodiment of the zoom lens
comprises the foremost or first lens group G1 of positive
refractive power located the closest to an object, the succeeding
second lens group G2 of negative refractive power, the third lens
group G3 of positive refractive power, the fourth lens group G4 of
positive refractive power, and the fifth lens group G5 of negative
refractive power, all the lens groups being arranged in this
order.
[0076] The first lens group G1 comprises a duplet of a meniscus
lens piece L1 of negative refractive power with its convex surface
oriented to the object and a lens piece L2 of positive refractive
power cemented with the meniscus lens piece L1, and a meniscus lens
piece L3 of positive refractive power with its convex surface
oriented to the object, all the lens pieces being arranged in this
order from the closest to the object in the foremost position to
the farthest in the rearmost position.
[0077] The second lens group G2 comprises a duplet of a lens piece
L4 of positive refractive power and a lens piece L5 of negative
refractive power cemented with the lens piece L4, another duplet of
a lens piece L6 of positive refractive power with its convex
surface oriented toward the object and a lens piece L7 of negative
refractive power cemented with the lens piece L6, and a meniscus
lens piece L8 of negative refractive power with its concave surface
oriented to the object, all the lens pieces being arranged in this
order from the closest to the object in the foremost position to
the farthest in the rearmost position.
[0078] The third lens group G3 comprises a biconvex lens piece L9,
a biconvex lens piece L10, a duplet of a lens piece L11 of positive
refractive power with its convex surface oriented to the object and
a lens piece L12 of negative refractive power cemented with the
lens piece L11, and another duplet of a biconcave lens piece L13
and a meniscus lens piece L14 of positive refractive power with its
convex surface oriented to the object, and cemented with the
biconcave lens piece L13, all the lens pieces being arranged in
this order from the closest to the object in the foremost position
to the farthest in the rearmost position.
[0079] The fourth lens group G4 comprises a biconvex lens piece
L15, and a duplet of a lens piece L16 of positive refractive power
with its convex surface oriented toward the object and a lens piece
L17 of negative refractive power cemented with the lens piece L16,
all the lens pieces being arranged in this order from the closest
to the object in the foremost position to the farthest from the
object in the rearmost position.
[0080] The fifth lens group G5 comprises a lens piece L18 of
negative refractive power with its convex surface oriented toward
the object, and a duplet of a biconcave lens piece L19 and a lens
piece L20 of positive refractive power cemented with the lens piece
L19, all the lens pieces being arranged in this order from the
closest to the object in the foremost position to the farthest in
the rearmost position.
[0081] During varying optical power from the wide-angle and to the
telephoto end, the second embodiment of the zoom lens has its first
lens group moved toward the object, its second lens group held in a
fixed position, its third lens group moved on a trajectory that
draws an are toward the imaging plane relative to the second lens
group, its fourth lens group moved on a trajectory that draws an
arc toward the imaging plane relative to the third lens group, and
its fifth lens group moved toward the object.
[0082] For focusing on an object at the near point, the fourth lens
group are moved toward the imaging plane. The duplet of the
cemented lens pieces L13 and L14 are moved in directions normal to
the optical axis so as to correct fuzziness of an image during
photographing.
[0083] Optical data of the second embodiment of the zoom lens are
provided in Table 4.
TABLE-US-00004 TABLE 4 NS R D Nd .nu.d 1 507.2915 3.0000 1.83400
37.34 2 170.5651 0.0200 1.56732 42.84 3 170.5651 10.0500 1.49700
81.61 4 -546.9417 0.3000 5 140.0409 9.1000 1.49700 81.61 6
6747.4128 D(6) 7 -462.7175 4.4000 1.80518 25.46 8 -59.7377 0.0100
1.56732 42.84 9 -59.7377 1.6000 1.75540 47.52 10 89.4635 1.7000 11
84.1934 4.0322 1.80518 25.46 12 -143.0460 0.0100 1.56732 42.84 13
-143.0460 1.4000 1.83481 42.72 14 103.1048 4.3467 15 -72.3495
1.5000 1.90366 31.31 16 -959.3316 D(16) 17 96.4840 4.8156 1.49700
81.61 18 -93.3616 0.2000 19 136.2135 3.8473 1.48749 70.44 20
-135.3488 0.2000 21 74.9337 5.3536 1.48749 70.44 22 -69.9732 0.0100
1.56732 42.84 23 -69.9732 1.5000 1.90366 31.31 24 -1625.6271
12.0000 25 -276.9348 1.2000 1.80393 37.39 26 24.9138 0.0100 1.56732
42.84 27 24.9138 4.7931 1.83950 29.48 28 112.4209 4.5000 29 STOP
0.0000 D(29) 30 82.8644 4.6000 1.50601 60.25 31 -68.5146 0.2000 32
38.3468 5.4000 1.50163 62.32 33 -58.6905 0.0100 1.56732 42.84 34
-58.6905 3.3708 1.90366 31.31 35 1283.2003 0.0000 36 0.0000 D(36)
37 101.8564 1.3000 1.83481 42.72 38 24.0855 5.7488 39 -73.4446
1.3504 1.48749 70.44 40 24.7023 0.0100 1.56732 42.84 41 24.7023
5.6000 1.66885 31.91 42 -3665.3014 D(42) 43 0.0000 2.0000 1.51680
64.20 44 0.0000 1.0000
[0084] Distances between the adjacent lens surfaces in several
pairs in the second embodiment of the zoom lens are given in Table
5 below as well as varied values of the focal distance f, the
F-number Fno, and the field angle .omega. for each of the
photographing positions at the wide-angle end (f=151.9125), at the
intermediate zooming range (f=300.56), and at the telephoto end
(f=582.2009), respectively.
TABLE-US-00005 TABLE 5 f 151.9125 300.5600 582.2009 Fno 4.94595
5.91814 6.77715 .omega. 7.9237 4.01640 2.07480 D(6) 64.0000
111.8284 141.2200 D(16) 34.6165 23.4740 2.0400 D(29) 28.9568
16.6652 23.1985 D(36) 9.6584 5.9504 3.1420 D(42) 51.0000 78.1421
95.8512
[0085] Distances between the adjacent lens surfaces in several
pairs in the second embodiment of the zoom lens during focusing on
an object at the near point for zooming settings at the wide-angle
end (f=151.9125), at the intermediate zooming range (f=300.56), and
at the telephoto end (f=582.2009), respectively, are given in Table
6 below as well as varied values of the focal length f upon
focusing on an object at infinite distance away and the distance
D(0) from the front surface of the first lens piece to the
object.
TABLE-US-00006 TABLE 6 f 151.9125 300.5600 582.2009 D(0) 2401.28
2353.45 2324.06 D(29) 27.6147 13.4871 14.3841 D(36) 11.0005 9.1285
11.9565
Embodiment 3
[0086] FIG. 9 is a vertical sectional view showing a lens
arrangement of a third embodiment of the zoom lens according to the
present invention. The third embodiment of the zoom lens comprises
the foremost or first lens group G1 of positive refractive power
located the closest to an object, the succeeding second lens group
G2 of negative refractive power, the third lens group G3 of
positive refractive power, the fourth lens group G4 of positive
refractive power, and the fifth lens group G5 of negative
refractive power, all the lens groups being arranged in this
order.
[0087] The first lens group G1 comprises a duplet of a meniscus
lens piece L1 of negative refractive power with its convex surface
oriented to the object and a lens piece L2 of positive refractive
power cemented with the meniscus lens piece L1, and a lens piece L3
of positive refractive power, all the lens pieces being arranged in
this order from the closest to the object in the foremost position
to the farthest in the rearmost position.
[0088] The second lens group G2 comprises a duplet of a lens piece
L4 of positive refractive power with its convex surface oriented
toward the object and a lens piece L5 of negative refractive power
cemented with the lens piece L4, another duplet of a meniscus lens
piece L6 of negative refractive power with its convex surface
oriented toward the object and a lens piece L7 of positive
refractive power cemented with the lens piece L6, and a meniscus
lens piece L8 of negative refractive power with its concave surface
oriented to the object.
[0089] The third lens group G3 comprises a biconvex lens piece L9,
a biconvex lens piece L10, a duplet of a lens piece L11 of positive
refractive power with its convex surface oriented to the object and
a lens piece L12 of negative refractive power cemented with the
lens piece L11, and another duplet of a biconcave lens piece L13
and a meniscus lens piece L14 of positive refractive power with its
convex surface oriented to the object, and cemented with the
biconcave lens piece L13, all the lens pieces being arranged in
this order from the closest to the object in the foremost position
to the farthest in the rearmost position.
[0090] The fourth lens group G4 comprises a biconvex lens piece
L15, and a duplet of a lens piece L16 of positive refractive power
with its convex surface oriented toward the object and a lens piece
L17 of negative refractive power cemented with the lens piece L16,
all the lens pieces being arranged in this order from the closest
to the object in the foremost position to the farthest from the
object in the rearmost position.
[0091] The fifth lens group G5 comprises a lens piece L18 of
negative refractive power with its convex surface oriented toward
the object, and a duplet of a biconcave lens piece L19 and a
meniscus lens piece L20 of positive refractive power with its
convex surface oriented to the object, and cemented with the lens
piece L19, all the lens pieces being arranged in this order from
the closest to the object in the foremost position to the farthest
in the rearmost position.
[0092] During varying optical power from the wide-angle and to the
telephoto end, the third embodiment of the zoom lens has its first
lens group moved toward the object, its second lens group held in a
fixed position, its third lens group moved on a trajectory that
draws an arc toward the imaging plane relative to the second lens
group, its fourth lens group moved on a trajectory that draws an
arc toward the imaging plane relative to the third lens group, and
its fifth lens group moved toward the object.
[0093] For focusing on an object at the near point, the fourth lens
group are moved toward the object. The duplet of the cemented lens
pieces L13 and L14 are moved in directions normal to the optical
axis so as to correct fuzziness of an image during
photographing.
[0094] Optical data of the third embodiment of the zoom lens are
provided in Table 7.
TABLE-US-00007 TABLE 7 NS R D Nd .nu.d 1 297.9129 2.8300 1.83400
37.34 2 135.0384 0.0200 1.56732 42.84 3 135.0384 9.3000 1.49700
81.61 4 -4966.1736 0.3000 5 146.0473 8.5000 1.49700 81.61 6
-1305.5193 D(6) 7 213.6104 4.2002 1.80518 25.46 8 -62.5956 0.0100
1.56732 42.84 9 -62.5956 1.5700 1.74645 49.97 10 144.9586 3.2900 11
-612.2359 1.4500 1.83404 40.21 12 48.5752 0.0100 1.56732 42.84 13
48.5752 3.2100 1.80518 25.46 14 152.1415 2.4500 15 -71.1073 1.4200
1.90366 31.31 16 2627.1686 D(16) 17 97.4108 3.9312 1.49700 81.61 18
-83.4307 0.2000 19 126.7004 3.1209 1.48749 70.44 20 -143.7416
0.2000 21 69.4530 4.8712 1.48749 70.44 22 -68.6082 0.0100 1.56732
42.84 23 -68.6082 1.4200 1.90366 31.31 24 -2644.7437 12.0500 25
-271.3050 1.2500 1.82533 40.81 26 28.0112 0.0100 1.56732 42.84 27
28.0112 3.9500 1.89851 30.99 28 101.7617 4.4401 29 STOP 0.0000
D(29) 30 89.3134 3.7900 1.52994 52.35 31 -63.6313 0.2000 32 36.8157
5.1142 1.50170 69.40 33 -56.3810 0.0100 1.56732 42.84 34 -56.3810
1.3200 1.90366 31.31 35 1002.5920 0.0000 36 0.0000 D(36) 37
101.3957 1.2500 1.81828 43.28 38 23.0588 5.9200 39 -51.4450 1.4000
1.48749 70.44 40 26.1939 0.0100 1.56732 42.84 41 26.1939 5.4332
1.72579 34.70 42 -206.0292 D(42) 43 0.0000 2.0000 1.51680 64.20 44
0.0000 1.0000
[0095] Distances between the adjacent lens surfaces in several
pairs in the third embodiment of the zoom lens are given in Table 8
below as well as varied values of the focal distance f, the
F-number Fno, and the field angle .omega. for each of the
photographing positions at the wide-angle end (f=153.8209), at the
intermediate zooming range (f=286.8109), and at the telephoto end
(f=485.2042), respectively.
TABLE-US-00008 TABLE 8 f 153.8209 286.8109 485.2042 Fno 4.95462
5.80954 6.48931 .omega. 8.0054 4.31340 2.55290 D(6) 64.9509
105.7871 129.7209 D(16) 29.9346 17.8473 2.2000 D(29) 27.7446
20.6475 22.7820 D(36) 9.7788 6.8423 4.4105 D(42) 51.3300 73.4510
89.3956
[0096] Distances between the adjacent lens surfaces in several
pairs in the third embodiment of the zoom lens during focusing on
an object at the near point for zooming settings at the wide-angle
end (f=153.8209), at the intermediate zooming range (f=286.8109),
and at the telephoto end (f=485.2042), respectively, are given in
Table 9 below as well as varied values of the focal length f upon
focusing on an object at infinite distance away and the distance
D(0) from the front surface of the first lens piece to the
object.
TABLE-US-00009 TABLE 9 f 153.8209 286.8109 485.2042 D(0) 2014.80
1973.96 1950.03 D(29) 26.0200 16.6583 13.9700 D(36) 11.5034 10.8315
13.2225
Embodiment 4
[0097] FIG. 13 is a vertical sectional view showing a lens
arrangement of a fourth embodiment of the zoom lens according to
the present invention. The fourth embodiment of the zoom lens
comprises the foremost or first lens group G1 of positive
refractive power located the closest to an object, the succeeding
second lens group G2 of negative refractive power, the third lens
group G3 of positive refractive power, the fourth lens group G4 of
positive refractive power, and the fifth lens group G5 of negative
refractive power, all the lens groups being arranged in this
order.
[0098] The first lens group G1 comprises a duplet of a meniscus
lens piece L1 of negative refractive power with its convex surface
oriented to the object and a lens piece L2 of positive refractive
power cemented with the meniscus lens piece L1, and a lens piece L3
of positive refractive power, all the lens pieces being arranged in
this order from the closest to the object in the foremost position
to the farthest in the rearmost position.
[0099] The second lens group G2 comprises a duplet of a lens piece
L4 of positive refractive power with its convex surface oriented
toward the object and a lens piece L5 of negative refractive power
cemented with the lens piece L4, another duplet of a meniscus lens
piece L6 of negative refractive power with its convex surface
oriented toward the object and a lens piece L7 of positive
refractive power cemented with the lens piece L6, and a meniscus
lens piece L8 of negative refractive power with its concave surface
oriented to the object.
[0100] The third lens group G3 comprises a biconvex lens piece L9,
a biconvex lens piece L10, a duplet of a lens piece L11 of positive
refractive power with its convex surface oriented to the object and
a lens piece L12 of negative refractive power cemented with the
lens piece L11, and another duplet of a biconcave lens piece L13
and a meniscus lens piece L14 of positive refractive power with its
convex surface oriented to the object, and cemented with the
biconcave lens piece L13, all the lens pieces being arranged in
this order from the closest to the object in the foremost position
to the farthest in the rearmost position.
[0101] The fourth lens group G4 comprises a biconvex lens piece
L15, and a duplet of a lens piece L16 of positive refractive power
with its convex surface oriented toward the object and a lens piece
L17 of negative refractive power cemented with the lens piece L16,
all the lens pieces being arranged in this order from the closest
to the object in the foremost position to the farthest from the
object in the rearmost position.
[0102] The fifth lens group G5 comprises a lens piece L18 of
negative refractive power with its convex surface oriented toward
the object, and a duplet of a biconcave lens piece L19 and a
meniscus lens piece L20 of positive refractive power with its
convex surface oriented to the object, and cemented with the lens
piece L19, all the lens pieces being arranged in this order on the
basis of the foremost first.
[0103] During shifting from the wide-angle end to the telephoto end
to vary optical power, the fourth embodiment of the zoom lens has
its first lens group moved toward the object, its second lens group
held in a fixed position, its third lens group moved on a
trajectory that draws an are toward the imaging plane relative to
the second lens group, its fourth lens group moved on a trajectory
that draws an arc toward the imaging plane relative to the third
lens group, and its fifth lens group moved toward the object.
[0104] For focusing on an object at the near point, the fourth lens
group are moved toward the object. The duplet of the cemented lens
pieces L13 and L14 are moved in directions normal to the optical
axis so as to correct fuzziness of an image during
photographing.
[0105] Optical data of the fourth embodiment of the zoom lens are
provided in Table 10.
TABLE-US-00010 TABLE 10 NS R D Nd .nu.d 1 426.3567 3.0000 1.83400
37.34 2 159.9066 0.0200 1.56732 42.84 3 159.9066 10.0500 1.49700
81.61 4 -684.4955 0.3000 5 140.0775 9.1000 1.49700 81.61 6
8733.4134 D(6) 7 558.1944 4.4000 1.80518 25.46 8 -61.1413 0.0100
1.56732 42.84 9 -61.1413 1.6000 1.72916 54.67 10 177.9802 2.6000 11
583.7869 1.5000 1.80450 39.64 12 50.6562 0.0100 1.56732 42.84 13
50.6562 3.4000 1.80518 25.46 14 142.9473 3.7000 15 -73.8510 1.5000
1.90366 31.31 16 515.2175 D(16) 17 432.7323 4.1000 1.49700 81.61 18
-112.9310 0.2000 19 73.5789 5.2184 1.48749 70.44 20 -95.0713 0.2000
21 87.0854 5.1506 1.48749 70.44 22 -66.1655 0.0100 1.56732 42.84 23
-66.1655 1.5000 1.90366 31.31 24 -710.1255 12.5500 25 -236.4657
0.9000 1.74400 44.79 26 27.5546 0.0100 1.56732 42.84 27 27.5546
4.1589 1.80610 33.27 28 99.2354 4.5500 29 STOP 0.0000 D(29) 30
65.1174 4.1342 1.51742 52.15 31 -65.1174 0.2000 32 50.5972 5.4000
1.51823 58.96 33 -48.1430 0.0100 1.56732 42.84 34 -48.1430 1.3000
1.90366 31.31 35 1899.0359 0.0000 36 0.0000 D(36) 37 113.8672
2.2800 1.83481 42.72 38 25.8597 6.9561 39 -55.4034 1.3000 1.48749
70.44 40 29.6386 0.0100 1.56732 42.84 41 29.6386 5.9000 1.72047
34.71 42 -175.0744 D(42) 43 0.0000 2.0000 1.51680 64.20 44 0.0000
1.0000
[0106] Distances between the adjacent lens surfaces in several
pairs in the fourth embodiment of the zoom lens are given in Table
11 below as well as varied values of the focal distance f, the
F-number Fno, and the field angle for each of the photographing
positions at the wide-angle end (f=152.1633), at the intermediate
zooming range (f=297.4851), and at the telephoto end (f=582.52),
respectively.
TABLE-US-00011 TABLE 11 f 152.1633 297.4851 582.5200 Fno 4.99224
5.87742 6.53711 .omega. 7.9436 4.07100 2.07820 D(6) 64.0000
111.2643 142.4400 D(16) 34.0551 23.2139 2.0400 D(29) 27.7980
17.1857 24.0639 D(36) 13.6386 8.2816 2.5000 D(42) 51.0000 77.8106
97.8880
[0107] Distances between the adjacent lens surfaces in several
pairs in the fourth embodiment of the zoom lens during focusing on
an object at the near point for photographing situation at the
wide-angle end (f=152.1633), at the intermediate zooming range
(f=297.4851), and at the telephoto end (f=582.52), respectively,
are given in Table 12 below as well as varied values of the focal
length f upon focusing on an object at infinite distance away and
the distance D(0) from the front surface of the first lens piece to
the object.
TABLE-US-00012 TABLE 12 f 152.1633 297.4851 582.5200 D(0) 2399.28
2352.02 2320.84 D(29) 26.1916 13.2535 12.8804 D(36) 15.2450 12.2138
13.6835
Embodiment 5
[0108] FIG. 17 is a vertical sectional view showing a lens
arrangement of a fifth embodiment of the zoom lens according to the
present invention. The fifth embodiment of the zoom lens comprises
the foremost or first lens group G1 of positive refractive power
located the closest to an object, the succeeding second lens group
G2 of negative refractive power, the third lens group G3 of
positive refractive power, the fourth lens group G4 of positive
refractive power, and the fifth lens group G5 of negative
refractive power, all the lens groups being arranged in this
order.
[0109] In the fifth embodiment of the zoom lens, the first lens
group G1 comprises a duplet of a meniscus lens piece L1 of negative
refractive power with its convex surface oriented to the object and
a lens piece L2 of positive refractive power cemented with the
meniscus lens piece L1, and a meniscus lens piece L3 of positive
refractive power with its convex surface oriented toward the
object, all the lens pieces being arranged in this order from the
closest to the object in the foremost position to the farthest from
the object in the rearmost position.
[0110] The second lens group G2 comprises a duplet of a lens piece
L4 of positive 8 refractive power with its convex surface oriented
toward the object and a lens piece L5 of negative refractive power
cemented with the lens piece L4, another duplet of a meniscus lens
piece L6 of negative refractive power with its convex surface
oriented toward the object and a lens piece L7 of positive
refractive power cemented with the lens piece L6, and a meniscus
lens piece L8 of negative refractive power with its concave surface
oriented to the object.
[0111] The third lens group G3 comprises a biconvex lens piece L9,
a biconvex lens piece L10, a duplet of a biconvex lens piece L11
and a lens piece L12 of negative refractive power cemented with the
lens piece L11, and another duplet of a biconcave lens piece L13
and a meniscus lens piece L14 of positive refractive power with its
convex surface oriented to the object, and cemented with the
biconcave lens piece L13, all the lens pieces being arranged in
this order from the closest to the object in the foremost position
to the farthest in the rearmost position.
[0112] The fourth lens group G4 comprises a biconvex lens piece
L15, and a duplet of a biconvex lens piece L16 and a lens piece L17
of negative refractive power cemented with the lens piece L16, all
the lens pieces being arranged in this order from the closest to
the object in the foremost position to the farthest from the object
in the rearmost position.
[0113] The fifth lens group G5 comprises a lens piece L18 of
negative refractive power with its convex surface oriented toward
the object, and a duplet of a biconcave lens piece L19 and a
biconvex lens piece L20 cemented with the lens piece L19, all the
lens pieces being arranged in this order on the basis of the
foremost first.
[0114] During shifting from the wide-angle end to the telephoto end
to vary optical power, the fifth embodiment of the zoom lens has
its first lens group moved toward the object, its second lens group
held in a fixed position, its third lens group moved on a
trajectory that draws an are toward the imaging plane relative to
the second lens group, its fourth lens group moved on a trajectory
that draws an are toward the imaging plane relative to the third
lens group, and its fifth lens group moved toward the object.
[0115] For focusing on an object at the near point, the fourth lens
group are moved toward the object. The duplet of the cemented lens
pieces L13 and L14 are moved in directions normal to the optical
axis so as to correct fuzziness of an image during
photographing.
[0116] Optical data of the fifth embodiment of the zoom lens are
provided in Table 13.
TABLE-US-00013 TABLE 13 NS R D Nd .nu.d 1 343.2915 3.0000 1.83400
37.34 2 145.9091 0.0200 1.56732 42.84 3 145.9091 10.0500 1.49700
81.61 4 -1465.0143 0.3000 5 146.8570 9.3000 1.49700 81.61 6
-2192.2330 D(6) 7 247.8836 4.5000 1.80518 25.46 8 -60.9978 0.0100
1.56732 42.84 9 -60.9978 1.6000 1.75243 49.57 10 122.8808 3.5590 11
-3272.8176 1.5000 1.83888 39.37 12 44.9185 0.0100 1.56732 42.84 13
44.9185 3.5140 1.80518 25.46 14 172.9348 2.7259 15 -65.8855 1.5000
1.90366 31.31 16 -8818.9517 D(16) 17 107.5605 4.2567 1.49700 81.61
18 -82.4101 0.2000 19 131.8612 3.5227 1.48749 70.44 20 -137.2545
0.2000 21 74.0878 5.3399 1.48749 70.44 22 -69.9110 0.0100 1.56732
42.84 23 -69.9110 1.5000 1.90366 31.31 24 -2310.5069 13.5458 25
-220.8383 1.2000 1.71680 45.46 26 29.9133 0.0100 1.56732 42.84 27
29.9133 4.1500 1.80610 33.27 28 95.4308 5.0000 29 STOP 0.0000 D(29)
30 80.8865 4.1200 1.50860 59.40 31 -64.5149 0.2000 32 37.7400
5.4200 1.50623 60.42 33 -57.0230 0.0100 1.56732 42.84 34 -57.0230
1.3000 1.90366 31.31 35 797.3134 D(35) 36 94.7210 1.3000 1.82563
41.77 37 24.4742 6.4000 38 -55.8634 1.3000 1.48749 70.44 39 25.9416
0.0100 1.56732 42.84 40 25.9416 5.6800 1.65673 32.70 41 -226.3658
D(41) 42 0.0000 2.0000 1.51680 64.20 43 0.0000 1.0000
[0117] Distances between the adjacent lens surfaces in several
pairs in the fifth embodiment of the zoom lens are given in Table
14 below as well as varied values of the focal distance f, the
F-number Fno, and the field angle .omega. for each of the
photographing positions at the wide-angle end (f=122.40), at the
intermediate zooming range (f=304.04), and at the telephoto end
(f=582.00), respectively.
TABLE-US-00014 TABLE 14 f 122.4004 304.0417 582.0046 Fno 4.5047
5.8152 6.5310 .omega. 10.023 4.070 2.129 D(6) 46.8750 111.4683
141.3470 D(16) 36.4322 21.0752 2.0150 D(29) 35.2507 19.3740 24.5725
D(35) 10.8554 6.7810 3.9750 D(41) 43.9427 79.2508 95.9185
[0118] Distances between the adjacent lens surfaces in several
pairs in the fifth embodiment of the zoom lens during focusing on
an object at the near point for photographing situation at the
wide-angle end (f=122.40), at the intermediate zooming range
(f=304.04), and at the telephoto end (f=582.00), respectively, are
given in Table 15 below as well as varied values of the focal
length f upon focusing on an object at infinite distance away and
the distance D(0) from the front surface of the first lens piece to
the object.
TABLE-US-00015 TABLE 15 f 122.4004 304.04 582.00 D(0) 2217.380
2152.787 2122.908 D(29) 34.11145 15.72925 14.53497 D(35) 11.99467
10.42577 14.01258
[0119] The values of the terms in the formulae (1) to (5) regarding
the first to fifth embodiments of the present invention are given
in Table 16 below:
TABLE-US-00016 TABLE 16 Embodiment 1 2 3 4 5 X1/fT - formula (1)
0.1336 0.1326 0.1335 0.1347 0.1623 f1/ (fw fT) - formula 0.7965
0.8312 0.8788 0.8265 0.9242 (2) f3/ (fw fT) - formula 0.3005 0.2462
0.2541 0.2665 0.2616 (3) (1 - .beta.a) .beta.b - formula -1.2043
-1.5548 -1.2205 -1.4781 -1.4517 (4) Lt/fT - formula (5) 0.6207
0.6457 0.7213 0.6509 0.6479
* * * * *