Abstract: Provided is a zoom lens including a plurality of lens units, which consist of, in order from an object side to an image side: a positive first lens unit; a negative second lens unit; and a rear lens group including a plurality of lens units and having a positive refractive power as a whole, the first lens unit including a negative lens G1n arranged closest to the object side, and a plurality of positive lenses arranged on the image side of the negative lens, and the rear lens group includes a positive lens Grp. A lens unit arranged closest to the image side in the rear lens group includes the positive lens Grp. At this time, an Abbe number of the negative lens G1n, a refractive index of the positive lens Grp, and back focuses at a wide-angle end and a telephoto end, respectively, are appropriately set.

Abstract: A zoom lens includes a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, and a rear lens group LB including a plurality of lens units and having positive refractive power. The rear lens group LB includes a lens unit LF configured to move during focusing and having negative refractive power, a lens unit LN disposed on the image side of the lens unit LF and having negative refractive power, and a lens unit LP disposed on the image side of the lens unit LN and having the largest positive refractive power among the lens units having positive refractive power. The lens units LP and LN move to the object side in a predetermined locus during zooming from the wide-angle end to the telephoto end, and the lens units LP and LF satisfy a predetermined conditional expression.

Abstract: An optical system includes a negative lens satisfying the following conditional expressions: 30??d?40, 1.225?[nd?(14.387/?d)]?1.276, and 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d is an Abbe number of the negative lens, ?gF is a partial dispersion ratio of the negative lens at a g-line and an F-line, and nd is a refractive index of the negative lens at a d-line.

Abstract: A conversion lens having a negative refractive power includes a positive lens GP. The positive lens GP satisfies all the following conditional expressions: 30??d?40, 1.225?[nd?(14.387/?d)]?1.276, and 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d is an Abbe number of the positive lens GP, ?gF is a partial dispersion ratio of the positive lens GP for g-line and F-line, and nd is a refractive index of the positive lens GP for d-line.

Abstract: A zoom lens includes a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, and a rear lens group LB including a plurality of lens units and having positive refractive power. The rear lens group LB includes a lens unit LF configured to move during focusing and having negative refractive power, a lens unit LN disposed on the image side of the lens unit LF and having negative refractive power, and a lens unit LP disposed on the image side of the lens unit LN and having the largest positive refractive power among the lens units having positive refractive power. The lens units LP and LN move to the object side in a predetermined locus during zooming from the wide-angle end to the telephoto end, and the lens units LP and LF satisfy a predetermined conditional expression.

Abstract: An optical system includes an optical element. When the optical element is disposed on a magnification side with respect to an intersection point between an optical axis and a chief paraxial ray, the optical element is a positive lens. When the optical element is disposed on a reduction side with respect to the intersection point, the optical element is a negative lens. The optical element satisfies all of the following conditional expressions: 30??d?40 1.225?[nd?(14.387/?d)]?1.276 0.4300?[?gF?(2.9795/?d)]?0.5010 where ?d is Abbe number of the optical element, ?gF is a partial dispersion ratio of the optical element for g-line and F-line, and nd is a refractive index of the optical element for d-line.

Abstract: The zoom lens according to the present invention consists of, in order from an object side to an image side, a positive first lens unit, a negative second lens unit, and a positive rear unit including at least four lens units. The second lens unit moves toward the object side during zooming from a wide angle end to a telephoto end, and an interval between each pair of adjacent lens units is changed during zooming. The rear unit includes a positive lens unit LP, which is arranged closest to the image side. Focal lengths of the zoom lens at the wide angle end and at the telephoto end, focal lengths of the first lens unit and the second lens unit, and a distance from the lens surface of the lens unit LP on the image side to an image plane at the telephoto end are each set appropriately.

Abstract: Provided is a zoom lens, including, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a rear unit including a plurality of lens units and having a positive refractive power as a whole, in which an interval between adjacent lens units is changed during zooming. The rear unit includes a focus unit having a positive refractive power, which is configured to move during focusing. An optical system arranged on the image side of the focus unit has a negative refractive power at a telephoto end. A focal length (ft) of the zoom lens at the telephoto end and a combined focal length (fpt) of an optical system arranged on the object side of the focus unit are each appropriately set.

Abstract: A zoom lens includes a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, and a rear lens group LB including a plurality of lens units and having positive refractive power. The rear lens group LB includes a lens unit LF configured to move during focusing and having negative refractive power, a lens unit LN disposed on the image side of the lens unit LF and having negative refractive power, and a lens unit LP disposed on the image side of the lens unit LN and having the largest positive refractive power among the lens units having positive refractive power. The lens units LP and LN move to the object side in a predetermined locus during zooming from the wide-angle end to the telephoto end, and the lens units LP and LF satisfy a predetermined conditional expression.

Abstract: An optical system used in an imaging apparatus includes an optical element. In a case where the optical element is disposed on a magnification side with respect to an intersection point of an optical axis and a chief paraxial ray, the optical element is a negative lens, and in a case where the optical element is disposed on a reduction side with respect to the intersection point, the optical element is a positive lens. The optical element is configured to satisfy all of the following conditional expressions: 30??d?40 1.225?[nd?(14.387/?d)]?1.276 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d represents an Abbe number of the optical element, ?gF is a partial dispersion ratio of the optical element for g-line and F-line, and nd is a refractive index of the optical element for d-line.

Abstract: A conversion lens having a negative refractive power includes a positive lens GP. The positive lens GP satisfies all the following conditional expressions: 30??d?40, 1.225?[nd?(14.387/?d)]?1.276, and 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d is an Abbe number of the positive lens GP, ?gF is a partial dispersion ratio of the positive lens GP for g-line and F-line, and nd is a refractive index of the positive lens GP for d-line.

Abstract: An optical system includes a negative lens satisfying the following conditional expressions: 30??d?40, 1.225?[nd?(14.387/?d)]?1.276, and 0.4300?[?gF?(2.9795/?d)]?0.5010, where ?d is an Abbe number of the negative lens, ?gF is a partial dispersion ratio of the negative lens at a g-line and an F-line, and nd is a refractive index of the negative lens at a d-line.

Abstract: An optical system includes an optical element. When the optical element is disposed on a magnification side with respect to an intersection point between an optical axis and a chief paraxial ray, the optical element is a positive lens. When the optical element is disposed on a reduction side with respect to the intersection point, the optical element is a negative lens. The optical element satisfies all of the following conditional expressions: 30??d?40 1.225?[nd?(14.387/?d)]?1.276 0.4300?[?gF?(2.9795/?d)]?0.5010 where ?d is Abbe number of the optical element, ?gF is a partial dispersion ratio of the optical element for g-line and F-line, and nd is a refractive index of the optical element for d-line.

Abstract: In an optical system including, in order from an object side to an image side: a front unit (LF) having a negative refractive power; an aperture stop; and a rear unit (LR) having a positive refractive power, the front unit (LF) includes a meniscus-shaped negative lens (g1) closest to the object side, and a focal length (fw) of the entire optical system, a focal length (fg1) of the meniscus-shaped negative lens (g1), and a curvature radius (R2) of a lens surface on the image side of the meniscus-shaped negative lens (g1) are appropriately set.

Abstract: A nonvolatile semiconductor memory device includes a first string including a first number of memory cells connected in series each storing therein information in a nonvolatile manner; and a second string including a second number of memory cells connected in series each storing therein information in a nonvolatile manner, wherein the second number is smaller than the first number.

Abstract: Provided is a zoom lens, including, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a rear unit including a plurality of lens units and having a positive refractive power as a whole, in which an interval between adjacent lens units is changed during zooming. The rear unit includes a focus unit having a positive refractive power, which is configured to move during focusing. An optical system arranged on the image side of the focus unit has a negative refractive power at a telephoto end. A focal length (ft) of the zoom lens at the telephoto end and a combined focal length (fpt) of an optical system arranged on the object side of the focus unit are each appropriately set.

Abstract: A zoom lens includes, in order from the object side to the image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a negative refractive power, and a rear lens group including a plurality of lens units and having a positive refractive power as a whole. The distances between adjacent lens units are changed during zooming. The third lens unit is moved during focusing. The focal length, fw, of the entire zoom lens system at the wide-angle end; the focal length, ft, of the entire zoom lens system at the telephoto end; the combined focal length, f12w, of the first and second lens units at the wide-angle end; and the combined focal length, f12t, of the first and second lens units at the telephoto end are appropriately set to satisfy predetermined conditions.

Abstract: A zoom lens includes an imaging lens unit having a positive refractive power and provided nearest to an image-side end, and a focusing lens unit having a positive refractive power and provided on an object side of the imaging lens unit. A distance between the imaging lens unit and the focusing lens unit changes during zooming. The focusing lens unit moves during focusing. The imaging lens unit includes, at a position thereof nearest to an object-side end, a negative meniscus lens component that is concave on the object side thereof.

Abstract: In an optical system including, in order from an object side to an image side: a front unit (LF) having a negative refractive power; an aperture stop; and a rear unit (LR) having a positive refractive power, the front unit (LF) includes a meniscus-shaped negative lens (g1) closest to the object side, and a focal length (fw) of the entire optical system, a focal length (fg1) of the meniscus-shaped negative lens (g1), and a curvature radius (R2) of a lens surface on the image side of the meniscus-shaped negative lens (g1) are appropriately set.

Abstract: An optical system (OL) includes a magnification conversion optical unit (EXT) configured to be insertable and removable at a position between an aperture stop (SP) and an image plane (IP) of the optical system in order to change a focal length of the optical system, a total lens length of the optical system is constant before and after insertion of the magnification conversion optical unit, and a length Lp on an optical axis from the aperture stop to the image plane of the optical system, and a length Le on the optical axis from a lens surface closest to an object side of the magnification conversion optical unit to the image plane when the magnification conversion optical unit is inserted are appropriately set.