An extender lens changes a focal length of an entire lens system after replacement to a longer focal length side than a focal length of a master lens by replacing a part of the master lens with the extender lens. The extender lens consists of, in order from an object side to an image side, a first lens group, and a negative second lens group. The first lens group is a lens group that has a positive refractive power as a whole and has a shortest focal length among lens groups consisting of one lens component or a plurality of consecutively arranged lens components. The extender lens satisfies a predetermined conditional expression.

A zoom lens includes, in order from an object side, a first lens group of which at least a part moves for focusing, a plurality of lens groups which move in zooming, an aperture stop, and a final lens group which does not move for zooming. The final lens group includes a separation element PR for separating an incident light thereon into a transmitted light and a reflected light, a relay unit LR having a positive refractive power on which the transmitted light is incident, and a relay unit LA having a positive refractive power on which the reflected light is incident. An inequality about Fwp/Fw is satisfied, where Fw is a focal length at a wide angle end of the zoom lens via the relay unit LR and FwP is a focal length at the wide angle end of the zoom lens via the relay unit LA.

A zoom lens system including, in order from an object side to an image side, a first lens unit having a positive refractive power that does not move for zooming, a second lens unit having a negative refractive power that moves during zooming, and a third lens unit having a positive refractive power that moves during zooming. In the zoom lens system, a distance between lens units that are adjacent to each other changes during zooming, the first lens unit includes a first a-lens unit that does not move for focusing, and a first b-lens unit that moves from the image side towards the object side during focusing from an infinite object to a near object, and the first a-lens unit comprises two positive lenses and two negative lenses.

A zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a fifth lens group in order from an object side. In a case of zooming, an interval with an adjacent lens group is changed. The third lens group includes two positive lenses consecutively arranged in order from a side closest to the object side to an image side. The fifth lens group consists of a negative meniscus lens having a concave surface toward the object side and a positive lens having a convex surface toward the object side in order from the object side to the image side.

There is provided a zoom lens, consisting of sequentially from an object side: a first lens group having a positive refractive power and a focusing function; a second lens group having a negative refractive power and having a variator function of performing zooming; a third lens group having a positive refractive power and a diaphragm; a fourth lens group having a positive refractive power, and having a compensator function of correcting a position of an imaging plane at the time of zooming; and a fifth lens group having a positive or negative refractive power, wherein the second lens group is moved to the imaging plane side from the object side along an optical axis, and the fourth lens group is moved along the optical axis in a state of fixing the first lens group, the third lens group, and the fifth lens group at the time of zooming from a wide angle end to a telephoto end, and only the first lens group is moved along the optical axis at the time of focusing.

A first lens group (G1) having positive refractive power, a front-side lens group (GX), an intermediate lens group (GM) having positive refractive power, and a rear-side lens group (GR) are arranged in order from an object side. The front-side lens group (GX) is composed of one or more lens groups and has a negative lens group At least part of the intermediate lens group (GM) is a focusing lens group (GF). The rear-side lens group (GR) is composed of one or more lens groups. Upon zooming, the first lens group (G1) is moved with respect to an image surface, a distance between the first lens group (G1) and the front-side lens group (GX) is changed, a distance between the front-side lens group (GX) and the intermediate lens group (GM) is changed, and a distance between the intermediate lens group (GM) and the rear-side lens group (GR) is changed.

A first lens group (G1) having positive refractive power, a second lens group (G2) having negative refractive power, a third lens group (G3) having positive refractive power, a fourth lens group (G4) having negative refractive power, and a fifth lens group (G5) having positive refractive power are arranged in order from an object, and zooming is performed by changing distances between each lens group, and the first lens group (G1) is composed of three or more lenses, the fourth lens group (G4) is composed of two or less lenses, and the fifth lens group (G5) is composed of two or less lenses and moves to an image surface side upon zooming from a wide angle end state to a telephoto end state, and the following conditional expression (1) is satisfied.

8.40<f1/(−f2)  (1) where, f1 denotes a focal length of the first lens group (G1), and f2 denotes a focal length of the second lens group (G2).

The present disclosure relates to a lens system and an imaging device including the lens system. The lens system may include a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group in sequence from an object side to an image side along an optical axis of the lens system. At least one of the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group may be adjustable along the optical axis of the lens system to adjust a focal length of the lens system. The lens system may satisfy $a\le \frac{f_2}{{\left(f_w.Math.f_t\right)}^{1/2}}\le b,c\le \frac{f_3}{{\left(f_w.Math.f_t\right)}^{1/2}}\le d,e\le \frac{f_4}{{\left(f_w.Math.f_t\right)}^{1/2}}\le f.$

A compact zooming optical system, an optical apparatus and a method for manufacturing the zooming optical system having a vibration reduction function, a high zooming ratio, a wide-angle view and superb optical performance are provided, the system including, in order from an object side: a first lens group G1 having positive refractive power; a second lens group G2 having negative refractive power; a third lens group G3 having positive refractive power; and a fourth lens group G4 having negative refractive power; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group G1 and the second lens group G2, a distance between the second lens group G2 and the third lens group G3 and a distance between the third lens group G3 and the fourth lens group G4 being respectively varied; the third lens group G3 having, in order from the object side, a first segment group G31 having positive refractive power and a second segment group G32; the second segment group G32 being moved to have a component in a direction perpendicular to the optical axis; and predetermined conditional expressions being satisfied.

A 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, each distance between adjacent lens units changes. During zooming from a wide-angle end to a telephoto end, the first lens unit moves toward the object side, a distance between the third lens unit and the fourth lens unit decreases, and a distance between the fourth lens unit and the fifth lens unit decreases. The number of optical elements each having a refractive power in the first lens unit is two or less. Predetermined conditions are satisfied.