A variable magnification optical system (ZL) comprises a preceding lens group (GA) having negative refractive power and a succeeding lens group (GB) having positive refractive power, which are arranged in order from the object side along an optical axis. The succeeding lens group (GB) has a focusing group (GF) and an image-side group (GC) disposed closer to the image side than the focusing group (GF), the focusing group (GF) moves to the image side along the optical axis from focusing on an object at infinity to focusing on a close-distance object, and the following conditional expression is satisfied.

1.80<fF/fBaw

FNow<3.40 where fF is the focal length of the focusing group (GF), fBaw is the focal length in the wide-angle end state of an image-side lens group (GBa) composed of lenses disposed on the image side from the focusing group (GF), and FNow is the F-number of the variable magnification optical system (ZL) in the wide-angle end state.

A zoom lens L0 consists of a first lens unit L1 having negative refractive power, a middle group Lm including one or more lens units, and a last lens unit having positive refractive power. The first lens unit L1 includes a first negative lens, a second negative lens, and a third negative lens that are arranged sequentially in an order from an object side to an image side. The number of negative lenses included in the first lens unit L1 is four or less. The middle group Lm includes a plurality of cemented lenses each having a cemented surface that is convex toward the object side, and includes a lens element Ln that is disposed closest to the image side among lens elements having negative refractive power included in the middle group Lm. The zoom lens L0 satisfies a predetermined inequality.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, and a rear group having a positive refractive power as a whole including at least one lens unit. During zooming from a wide-angle end to a telephoto end, a distance between adjacent lens units changes. The first lens unit includes at least three negative single lenses, and a predetermined condition is satisfied.

A zoom lens has a four-group zoom configuration, in order from the object side to the image side, consisting of negative, positive, positive, and positive refractive power. The zoom lens carries out zooming from the wide-angle end to the telephoto end mainly by changing the distance between the third lens group and the fourth lens group. Also, the distance between the second lens group and the third lens group may be decreased in the zooming. Focusing is carried out mainly by moving the second lens group along the optical axis. Such a zoom lens is thin and small in size, and has a great imaging performance.

A zoom optical system includes a plurality of lens units, the plurality of lens units consist of lens units having a positive refractive power and lens units having a negative refractive power, and the lens units having a positive refractive power include a positive lens unit and an image-side positive lens unit, the image-side positive lens unit is not moved, in the lens plurality of units, a space between the lens units disposed adjacently is changed at a time of zooming, at a time of focusing, or at a time of zooming and at a time of focusing, the positive lens unit includes a predetermined positive lens satisfying the following Conditional Expression (2), and the following Conditional Expression (1) is satisfied:

0.1≦fGBUN1/fGPM≦2.1  (1), and

60.8≦νdGPMP1≦100.0  (2).

A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and three or more lens units. A distance between adjacent lens units varies during zooming. A predetermined condition is satisfied.

A zoom lens includes in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power. The first lens unit includes at least two negative lens components. The number of lenses in the third lens unit is larger than the number of lenses in the second lens unit. At the time of zooming from a wide angle end to a telephoto end, distances between lens units change, and the first lens unit, after moving toward an image side, moves toward the object side. In zooming in a state of being focused to an object at infinity, a distance between the second lens unit and the third lens unit becomes the widest at the wide angle end.

The present disclosure is directed to an optical system internally having an intermediate imaging position that is conjugated to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, respectively, the optical system including: a magnification optical system having A (A is an integer of three or more) pieces of lens elements, positioned on the magnification side with respect to the intermediate imaging position; and a relay optical system having B (B is an integer of two or more) pieces of lens elements, positioned on the reduction side with respect to the intermediate imaging position. A first lens group composed of β pieces (β is one or more and less than B) of lens elements positioned first from the magnification side in the relay optical system has a negative power.

The disclosure provides a zoom lens assembly, which sequentially includes from an object side to an image side along an optical axis: a first lens group; a second lens group with a positive refractive power, spaced from the first lens group by a first air space and movable on the optical axis; a third lens group with a positive refractive power, spaced from the second lens group by a second air space and movable on the optical axis; and a fourth lens group, spaced from the third lens group by a third air space; wherein a Total Track Length (TTL) of the zoom lens assembly and a difference Δf between an effective focal length of the zoom lens assembly at a wide end and an effective focal length of the zoom lens assembly at a tele end satisfy 2.5<TTL/|Δf|<4.0.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and three or more lens units. A distance between adjacent lens units varies during zooming. A predetermined condition is satisfied.