Tamron Company, Ltd.

Akio Arakawa

Yuichi Muramatsu

Dayong Li

Lai Wei

Yuuichi Muramatsu

A variable power zoom lens of four groups of lens pieces respectively exerting positive, negative, positive, and positive refractivities varies the power from the wide-angle end to the telephoto end as a result of the 1st and 2nd lens groups being separated more, the 2nd and 3rd lens groups, and the 3rd and 4th lens groups, coming closer to each other. The 3rd lens group has a leading set of lens pieces closer to the object side having a positive refractivity as a whole and the trailing set of lens pieces have negative refractivity as a whole, and the trailing set alone are moved to be orthogonal to the optical axis to compensate for defocus in the imaging plane. The 2nd lens group is displaced closer to objects for focusing.

High variable power zoom lens

Zoom lens for SLR digital cameras. The lens is at least 75 degrees wider in field angle at the wide-angle end, about 3 to 4 in f-stops at the wide-angle end and approximately 6 to 7 at the telephoto end, and about a 15:1 zoom range. Four groups of lens pieces exert positive, negative, positive, and positive refractivities from the wide-angle end to the telephoto end as a result of the 1st and 2nd lens groups being split more, the 2nd and 3rd lens groups coming closer to each other, and the 3rd and 4th lens groups also coming closer to each other. The 3rd lens group has the leading set of lens pieces closer to objects and the trailing set of lens pieces can be orthogonal to the optical axis to compensate for defocus in the imaging plane. The 2nd lens group is displaced closer to objects for focusing.

Anti-vibration zoom lens optics of four lens groups where a unit associated with an aperture stop and an anti-vibration unit can be spaced apart from each other without interference between their driving mechanisms. The four groups include a leading, first lens group of positive refractivity, a succeeding second lens group of negative refractivity, a third lens group of positive refractivity, and a trailing, fourth lens group of positive refractivity all arranged in this order from the front end closest to the object to the rearmost. The fourth lens group include three subsets of lens pieces, a leading, first subset, a succeeding, second subset, and a trailing, third subset all arranged in this order from the front end closest to the object to the rearmost, and the second subset of lens pieces are moved perpendicular to the optical axis to compensate for blur in the imaging plane.

Anti-vibration zoom lens optics

This large magnification factor zoom lens includes, in an order arranged from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power. The third lens group includes, in an order arranged from the object side, a positive lens, a positive lens, a positive meniscus lens having a larger radius of curvature on an image surface side, and a negative lens. The positive lens has an aspherical surface on an object side.

Large magnification factor zoom lens

The present invention is directed to a compact large-aperture-ratio inner-focusing telephoto zoom lens of the reduced total lens extension where minimizing a photo-shooting distance down to as short as 1 meter does not cause the lens optics to displace accordingly greater during the focusing. The large-aperture-ratio inner-focusing telephoto zoom lens has four groups of lens pieces, namely, the 1st lens group of positive refractive power, the 2nd lens group of negative refractive power, the 3rd lens group of positive refractive power, and, the 4th lens group of positive refractive power arranged in series on the basis of 'closer to a subject first,' and that has the 2nd and 3rd lens groups moved along the optical axis to vary a magnification power. In such a telephoto zoom lens, the 1st lens group includes the leading subgroup of lens pieces or foremost lens subgroup GF and the trailing subgroup of lens pieces or rear lens subgroup GR where the GF has two of a concave lens piece and a convex lens piece cemented into a single piece of composite lens while the GR has a composite lens of one concave lens piece and two convex lens pieces in series. The rear lens subgroup GR in the 1st lens group is moved along the optical axis for the focusing, and the telephoto zoom lens has an optical property that satisfies requirements as follows:1.3&#x3c;1/1.9 &#x2003;&#x2003;(1)where f1 is a focal length of the 1st lens group, and fw is a focal length of the telephoto zoom lens in the wide-angle view mode.

Telephoto zoom lens

The present invention is directed to a high variable power zoom lens that ensures a flange-back or a backfocal distance required for typical 35-mm film cameras while keeping an angle of view sufficient to cover the wide-angle for an APS-size imaging plane dimensioned smaller than 35 mm. The high variable power zoom lens has the first lens group Lof positive refractivity closest to the subject, the second lens group Lof negative refractivity second closest to the subject, the third lens group Lof positive refractivity, and the fourth lens group Lof positive refractivity farthest from the subject, and the zoom lens satisfies the requirements 0.6&#x2266;|f|/fW&#x2266;0.73 where fis the focal length of the second lens group and fW is the focal length of the entire optics moved to the wide-angle end, and also satisfies the requirements 2.2&#x2266;f/fW&#x2266;3.7 where fis the focal length of the third lens group.

The invention discloses a macro lens that takes a retrofocusing function for the purpose of downsizing. The macro lens employs a floating mechanism to cover a wide photographing range from the equi-magnification to the infinity, and especially, attains a great imaging performance by appropriately compensating for spherical aberration, comatic aberration, and chromatic aberration of magnification. The macro lens comprised of first to fifth lenses in the order closer to the object; that is, the first lens serving as a negative meniscus lens with a convex surface oriented to the object, the fourth lens as a negative lens with a concave surface of great curvature oriented to the image plane, and the fifth lens as a negative lens with a surface of great curvature oriented to the object. The macro lens satisfies conditions as expressed in the following formulae:0.6&#x2266;1/&#x2266;1.3 &#x2003;&#x2003;(1)0.9&#x2266;4/5&#x2266;1.5 &#x2003;&#x2003;(2)where F is a focal length of the entire lens system, F1 is a focal length of the first lens, F4 is a focal length of the fourth lens, and F5 is a focal length of the fifth lens.

Macro lens

A macro lens comprised of a front lens group of a retrofocus type and a rear lens group of which component lenses are aligned in the order from the closest to the subject. The front lens group includes a first lens of a negative meniscus lens having its convex surface projecting toward the object, a second lens of a positive lens having its one surface with greater curvature oriented toward the object, a third lens of a positive lens having its one surface with greater curvature oriented toward the object, a fourth lens of a negative lens having its concave surface with greater curvature oriented toward the imaging plane, fifth and sixth lenses of a junction lens in combination of a negative lens with a positive lens, the negative lens having its one surface with greater curvature oriented toward the object, across a space having an aperture stop, and a seventh lens of a positive lens having its one surface with greater curvature oriented toward the imaging plane, the rear lens group including an eighth negative lens and a ninth positive lens, the macro lens providing relations expressed as follows:1.0&#x3c;|&#x3c;1.3&#x2003;&#x2003;(1)4.0&#x3c;|&#x3c;6.0&#x2003;&#x2003;(2)where Fis a focal length of the first lens, Fis the focal length of the rear lens group, and Fis the focal length of the total optics of the.

Growing community of inventors

Saitama, Japan

Akio Arakawa