Abstract: A zoom lens including, in order from an object side: a positive first lens unit; a negative second lens unit; and a positive third lens unit, in which: an interval between the first and second lens units is increased, and an interval between the second and third lens units is decreased during zooming from a wide angle end to a telephoto end; the second lens unit is an image stabilizing lens unit which moves with a component of motion in a direction perpendicular to an optical axis whereby an imaging position is moved in the direction of motion perpendicular to the optical axis; and a focal length of an entire system at the wide angle end, a focal length of the first lens unit, and a movement amount of the first lens unit during zooming from the wide angle end to the telephoto end are each set appropriately.

Abstract: The zoom lens includes, 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, a third lens unit having a positive refractive power, a fourth lens unit having a positive refractive power, and a fifth lens unit having a negative refractive power. During zooming, the second lens unit is not moved and the first, third and fifth lens units are moved. A distance between the first and second lens units at a telephoto end is larger than that at a wide-angle end, a distance between the second and third lens units at the telephoto end is smaller than that at the wide-angle end. A condition of 0.7<f3/f4<1.5 is satisfied where f3 represents a focal length of the third lens unit, and f4 represents a focal length of the fourth lens unit.

Abstract: A zoom lens including, in order from an object side; a positive first lens unit, a negative second lens unit; and a positive third lens unit, in which: an interval between the first and second lens units is increased, and an interval between the second and third lens units is decreased during zooming from a wide angle end to a telephoto end; the second lens unit is an image stabilizing lens unit which moves with a component of motion in a direction perpendicular to an optical axis whereby an imaging position is moved in the direction of motion perpendicular to the optical axis; and a focal length of an entire system at the wide angle end, a focal length of the first lens unit, and a movement amount of the first lens unit during zooming from the wide angle end to the telephoto end are each set appropriately.

Abstract: The zoom lens includes, 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, a third lens unit having a positive refractive power, a fourth lens unit having a positive refractive power, and a fifth lens unit having a negative refractive power. During zooming, the second lens unit is not moved and the first, third and fifth lens units are moved. A distance between the first and second lens units at a telephoto end is larger than that at a wide-angle end, a distance between the second and third lens units at the telephoto end is smaller than that at the wide-angle end. A condition of 0.7<f3/f4<1.5 is satisfied where f3 represents a focal length of the third lens unit, and f4 represents a focal length of the fourth lens unit.

Abstract: An optical system includes, in order from an object side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. The optical system satisfies: 1.70?Yt/Yw?2.5, Y=2×f×sin(?/2) (85°???90°), and 3.45?bfw/|f1|?7, where fw is the shortest focal length, ft is the longest focal length, f is an arbitrary focal length that satisfies fw?f?ft, ? is an angle between the optical axis and a principal ray of an off-axis light flux incident upon a lens surface closest to the object, Y is a formed image height of a ray incident at the angle ?, Yw is the largest image height at the shortest focal length, Yt is the largest image height at the longest focal length, f1 is a focal length of the first lens unit, and bfw is a back focus at the shortest focal length.

Abstract: An optical system includes, in order from an object side to an image side, a first lens unit, a stop, and a second lens unit. The first lens unit includes a first negative lens having a meniscus shape and a negative refractive power at a position closest to the object side and a negative lens Gn having a negative refractive power at a position closer to the image side than the first negative lens. The second lens unit includes a positive lens Gp having a positive refractive power. A material of each of the negative lens Gn and the positive lens Gp satisfies the following condition: ?gF?(?0.001682·?d+0.6438)?0.01 where “?d” denotes an Abbe number of a lens material and “?gF” denotes a relative partial dispersion with respect to g-line light and F-line light.

Abstract: An optical system includes, in order from an object side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. The optical system satisfies: 1.70?Yt/Yw?2.5, Y=2×f×sin(?/2))(85°???90°), and 3.45?bfw/|f1|?7, where fw is the shortest focal length, ft is the longest focal length, f is an arbitrary focal length that satisfies fw?f?ft, ? is an angle between the optical axis and a principal ray of an off-axis light flux incident upon a lens surface closest to the object, Y is a formed image height of a ray incident at the angle ?, Yw is the largest image height at the shortest focal length, Yt is the largest image height at the longest focal length, f1 is a focal length of the first lens unit, and bfw is a back focus at the shortest focal length.

Abstract: An optical system includes, in order from an object side to an image side, a first lens unit, a stop, and a second lens unit. The first lens unit includes a first negative lens having a meniscus shape and a negative refractive power at a position closest to the object side and a negative lens Gn having a negative refractive power at a position closer to the image side than the first negative lens. The second lens unit includes a positive lens Gp having a positive refractive power. A material of each of the negative lens Gn and the positive lens Gp satisfies the following condition: ?gF?(?0.001682·?d+0.6438)?0.01 where “?d” denotes an Abbe number of a lens material and “?gF” denotes a relative partial dispersion with respect to g-line light and F-line light.

Abstract: Provided is a zoom lens system including: in order from an object side to an image side, a first lens unit having a positive refractive power; an aperture stop; and a second lens unit, in which the first lens unit includes a first-a lens unit having a positive refractive power and a first-b lens unit having a negative refractive power which moves along an optical axis in focusing, the first-b lens unit includes at least one negative lens and at least one positive lens, and the following conditional expression is satisfied: 0.020<?gF1?0.6438+0.001682×vd1<0.100, where ?gF1 denotes a partial dispersion ratio of a material of the positive lens, and vd1 denotes Abbe number of the positive lens.

Abstract: Provided is a zoom lens system including: in order from an object side to an image side, a first lens unit having a positive refractive power; an aperture stop; and a second lens unit, in which the first lens unit includes a first-a lens unit having a positive refractive power and a first-b lens unit having a negative refractive power which moves along an optical axis in focusing, the first-b lens unit includes at least one negative lens and at least one positive lens, and the following conditional expression is satisfied: 0.020<?gF1?0.6438+0.001682×vd1<0.100, where ?gF1 denotes a partial dispersion ratio of a material of the positive lens, and vd1 denotes Abbe number of the positive lens.