Olympus Optical Company, Ltd.

Olympus Corporation

Takanori Yamanashi

Katsuhiro Takada

Yuji Miyauchi

Yasuji Ogata

Norihiko Aoki

Yuko Kobayashi

Noriyuki Iyama

Masashi Hankawa

The invention relates to an electronic image pickup system that enables a wide image-pickup, and ensures that even when an image is printed, sufficient image quality and clearness are obtained from the center to as far as the margin of the image and the image of a subject is depicted with a sense of extension. The electronic image pickup system comprises an image-formation optical systemfor forming an image of a subject and an electronic image pickup devicelocated on an image side of the image-formation optical system for obtaining image information on the image. The angle between the farthest-off-axis chief ray incident on the farthest off-axis site on an image pickup plane of the electronic image pickup device and an axial chief ray incident on the center of the image pickup plane satisfies condition (1) for determining the angle of view suitable to obtain the sense to extension demanded for landscape photography and sharpness all over the image and condition (2) for allowing a light bundle incident on the image pickup device to be substantially vertically incident on the image pickup plane. The image pickup devicesatisfies condition (3) for determining the effective number of pixels on the image pickup device or the maximum number of recording pixels by signal processing.

Image pickup system

The invention relates to a two-group zoom lens of &plus;&minus; construction, which, albeit having a high zoom ratio, is reduced in length not only at the wide-angle end but also at the telephoto end and has a low telephoto ratio at the telephoto end where the length of the system becomes longest. The zoom lens comprises a first lens group G1 having positive refracting power and a second lens group G2 having negative refracting power. For zooming from the wide-angle end to the telephoto end of the system, each lens group moves toward the object side while the spacing between the first and second lens groups G1 and G2 becomes narrow. Specific conditions for the focal length of the second lens group G2, the amount of movement of the second lens group G2 and the zoom ratio shared by the second lens group G2 are satisfied.

Zoom lens

A compact zoom lens system maintains sufficient image-formation capabilities at a wide-angle end of greater than 700 and at a zoom ratio of greater than about 10. The zoom lens system comprises a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group. For zooming from a wide-angle end to a telephoto end, the first to fifth lens groups are all movable. The first and third lens groups move toward the object side. Also, the spaces between the first and second lens groups and between the third and fourth lens groups widen. At least the fourth lens group or the fifth lens group makes a non-linear movement, compensating for a fluctuation of an image plane position with zooming. Focusing is carried out by moving the first and second lens groups as an integral unit.

Zoom lens system

The invention relates to a compact zoom lens system which can be applied to a relatively large image pickup device and can maintain sufficient image-formation capability even at a wide-angle end of 70&deg; or greater and a zoom ratio of about 10 or greater. The zoom lens system comprises a first lens group G having positive refracting power, a second lens group G having negative refracting power, a third lens group G having positive refracting power, a fourth lens group G having negative refracting power and a fifth lens group G . During zooming from the wide-angle end to the telephoto end of the system, the lens groups G to G are all moving. The first lens group G and the third lens group G move toward the object side in the process of zooming in such a way that-the spacings between the first and second lens groups G and G and the third and fourth lens groups G and G become wide, and at least the fourth lens group G or the fifth lens group G moves nonlinearly, so that fluctuations of an image plane position with zooming can be compensated for. Conditions for defining the power profiles of the first to fifth lens groups G to G are satisfied.

The invention relates to a two-group zoom lens of &plus;&minus; construction, which, albeit having a high zoom ratio, is reduced in length not only at the wide-angle end but also at the telephoto end and has a low telephoto ratio at the telephoto end where the length of the system becomes longest. The zoom lens comprises a first lens group G having positive refracting power and a second lens group G having negative refracting power. For zooming from the wide-angle end to the telephoto end of the system, each lens group moves toward the object side while the spacing between the first and second lens groups G and G becomes narrow. Specific conditions for the focal length of the second lens group G , the amount of movement of the second lens group G and the zoom ratio shared by the second lens group G are satisfied.

A wide-angle zoom lens system having a short optical total length not only at the wide-angle end but also at the telephoto end and a reduced telephoto ratio despite the fact that it has a high zoom ratio, with a view to achieving a reduction in size of cameras. The zoom lens system has a first lens unit G of positive refractive power, a second lens unit G of negative refractive power, a third lens unit G of positive refractive power, and a fourth lens unit G of negative refractive power. When the zoom lens system is zoomed from the wide-angle side to the telephoto side, each of the lens units moves toward the object side such that the space between the first lens unit G and the second lens unit G increases, whereas the space between the third lens unit G and the fourth lens unit G decreases. The zoom lens system satisfies a condition concerning the focal lengths of the first lens unit G and the fourth lens unit G , a condition concerning the amount of movement of the fourth lens unit G and a condition concerning the zoom ratio assigned to the fourth lens unit G

Wide-angle zoom lens system

The object of the invention is to reduce the size of a camera by the provision of a zoom lens system which has a high zoom ratio and a small telephoto ratio at the wide-angle and telephoto end, and is simple in lens arrangement and reduced in size during lens collapsing. The zoom lens system comprises a positive first lens group G , a positive second lens group G and a negative third lens group G . For zooming from a wide-angle end to a telephoto end of the system, each lens group moves toward the object side while a spacing between the first lens group and the second lens group becomes wide and a spacing between the second lens group and the third lens group becomes narrow. The first lens group G comprises at least one set of a negative lens and a positive lens. The second lens group G includes an aperture stop and comprises at least one set of a negative lens and a positive lens. The third lens group G comprises one set of a positive lens and a negative lens. Specific conditions for an actual air space between the second and third lens groups G and G , the focal length of the third group G and the zoom ratio shared by the third group G are all satisfied.

The invention relates to a zoom lens system which, albeit having a high zoom ratio, is reduced in terms of length during lens collapsing and at the wide-angle end as well as the telephoto end, with well-corrected aberrations. The zoom lens system comprises a front lens group G,located nearest to the object side and a rear lens group G,located nearest to the image side with at least one lens group located between G,and G,The group G,has positive or negative refracting power and the group G,has negative refracting power. For zooming from the wide-angle end to the telephoto end, a separation between adjacent lens groups varies. Specific conditions are satisfied with respect to the focal length of G,the amount of movement of G,and the zoom ratio shared by G

The invention provides a wide-angle yet high-magnification zoom lens system which can have satisfactory performance with a simple lens arrangement, and an optical system which can make satisfactory correction for off-axis aberrations becoming a problem in taking wide-angle shots. The zoom lens system comprises a first lens group G1 having negative power, a second lens group G2, a third lens group G3 having positive power, a fourth lens group G4 having negative power and a fifth lens group G5. For zooming, the first group G1 moves nonlinearly and the second group G2 to the fifth group G5 moves toward an object side of the system on a wide-angle end basis. For a wide-angle end to a telephoto end of the system, the lens groups move such that spacings between the first group G2 and the second group G2, between the second group G2 and the third group G3 and between the fourth group G4 and the fifth group G5 become narrow while a spacing between the third group G3 and the fourth group G4 becomes wide. An aspherical surface is at least used in the first group G1. The zoom lens system satisfies a condition 0.7&lt;.vertline.f.sub.1 /f.sub.w &lt;3 where f.sub.1 is a focal length of the first group G1 and f.sub.w is a focal length of the zoom lens system at a wide-angle end of the system.

The invention relates to a zoom lens system having stable performance and a high magnification, which comprises a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having positive refracting power and a fourth lens group G4 having negative refracting power. For zooming from a wide-angle end to a telephoto end of a zooming area having a continuous zooming action, an intergroup space of each lens group is varied. At least one group of the four lens groups is moved to define an extended wide-angle point SW that is a discontinuous zooming point at a position where a focal length thereof becomes shorter than the wide-angle end of the zooming area. At least one lens group of the four lens groups is moved to define an extended telephoto point ST that is a discontinuous zooming point at a position where a focal length thereof becomes longer than the telephoto end of the zooming area.

A wide-angle lens system which has a long back focal length comprising a first lens unit having a negative power, a second lens unit having a positive power and a third lens unit having a positive power: the first lens unit being composed of a 1-1 positive lens unit which is composed only of a positive lens component and a 1-2 negative lens unit which is composed only of negative lens components, the third lens unit being composed of a 3-1 subunit which comprises at least a negative lens component and a 3-2 positive subunit which comprises at least a negative lens component, the 3-1 subunit being composed of a first negative lens component and a second positive lens component, and the 3-2 subunit being composed of a third negative lens component and a fourth positive lens component.

Wide-angle lens system

A telephoto lens system consisting of a front lens group and a rear lens group: the front lens group being composed of a first lens unit which is composed only of a positive lens components and a second lens unit which is composed only of negative lens components, and the rear lens group being composed of a third positive lens unit, a fourth negative lens unit and a fifth positive lens unit. This lens system has a back focal length long enough to permit disposing filters such as a low pass filter and optical path splitting members.

Lens system

The present invention relates to a telephoto zoom lens system which is less variable in terms of aberrations incidental to zooming and focusing, and is of high image quality and large aperture ratio as well, and which consists essentially of a first lens group G1 having a positive refracting power, a second lens group G2 having a negative refracting power, a third lens group G3 having a negative refracting power, a fourth lens group G4 having a positive refracting power and a fifth lens group G5 having a positive refracting power. For zooming from the wide-angle zone to the telephoto zone, the second and third lens groups G2 and G3 are moved in conformity to specific conditional inequalities while the first and fifth lens groups G1 and G5 remain fixed, and fourth lens group G4 is moved separately from the movable lens groups G2 and G3 while acting primarily as means for compensating for an image surface position. Conditions concerning the zoom ratio that the second and third lens groups G2 and G3 bear and the zooming function of the third lens group G3 as well as conditions that the separation between the second and third lens groups G2 and G3 should be larger at the wide-angle end than at the telephoto end are all satisfied.

A standard lens system composed, in order from the object side, of a first lens unit having a positive refractive power, an aperture stop, a second lens unit having a positive refractive power and a third lens unit having a negative refractive power: the first lens unit being composed of at least one positive meniscus lens component which has a convex surface on the object side, and at least one doublet which consists of a positive meniscus lens component and a negative lens component; the second lens unit being composed of at least one cemented doublet which consists of a negative lens element and a positive lens element, and a positive lens component; and the third lens unit being composed of at least one positive lens component and a negative lens component or at least one negative lens component.

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Kokubunji, Japan

Takanori Yamanashi