The invention provides a projection zoom lens and a projector. The projection zoom lens includes a first lens group and a second lens group sequentially arranged along an optical axis from a screen end to an image source end. The first lens group has a negative refractive power and includes a first lens, a second lens, and a third lens. The second lens group has a positive refractive power and includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens. The first lens to the twelfth lens are sequentially arranged along the optical axis from the screen end to the image source end, and the refractive powers of the first lens to the twelfth lens are negative, negative, positive, positive, positive, negative, negative, positive, positive, negative, positive, and positive.

A zoom lens consisting of, in order from an object side to an image side, a first lens unit having a negative refractive power, and a rear lens unit having one or more lens units and having a positive refractive power as a whole. Intervals between adjacent lens units change during zooming. The first lens unit has at least three meniscus lenses each having a negative refractive power and a convex shape toward the object side. At least one of the at least three meniscus lenses includes an aspherical surface having a positive aspherical amount. A predetermined condition is satisfied.

A zoom lens includes, in order from an object side to an image side, a first lens unit having negative refractive power and a second lens unit having positive refractive power. A distance between adjacent lens units changes during zooming. The first lens unit includes a plurality of lenses, the plurality of lenses consisting of a negative lens having a concave lens surface on the image side, and a positive lens having a convex lens surface on the object side and disposed on the image side of the negative lens via an air gap. A predetermined condition is satisfied.

An optical system (LS) Includes lenses (L22,L23) satisfying the following conditional expressions,

vdLZ<35.0, and

0.702<gFLZ+(0.00316dLZ),

where vdLZ: Abbe number of the lens with reference to d-line, and gFLZ: a partial dispersion ratio of the lens, wherein gFLZ is defined by the following expression,

gFLZ(ngLZnFLZ)/(nFLZnCLZ). wherein a refractive index of the lens with reference to g-line is ngLZ, a refractive index of the lens with reference to F-line is nFLZ, and a refractive index of the lens with reference to C-line is nCLZ.

An optical system LO includes in this order from an object side to an image side, a first lens unit FL, an aperture stop SP, and a second lens unit RL having a positive refractive power. The first lens unit FL includes at least three negative lenses including in order from the object side to the image side, negative lenses (G1N), (G2N), and (G3N). At least one lens surface of the negative lenses (G1N), (G2N), and (G3N) is an aspherical surface that satisfies a predetermined conditional 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 second lens unit having a positive refractive power. A distance between the first lens unit and the second lens unit changes during zooming. The second lens unit includes an aperture stop and two or more negative lenses. The zoom lens satisfies specified conditional expressions.

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 second lens unit having a positive refractive power, a distance between the first lens unit and the second lens unit changing during zooming. A predetermined condition is satisfied.

An ocular lens includes from an object side: a first lens group having negative refracting power, and a second lens group having positive refracting power. An object-side focal plane of the second lens group is positioned between the first lens group and the second lens group. The first lens group includes, from the object side: a meniscus first A lens component whose convex surface is directed toward the object side, and a first B lens component having negative refracting power. The second lens group includes, in a position closest to the object side, a meniscus second A lens component whose concave surface is directed toward the object side, and satisfies conditional expressions.

An optical system (LS) includes lenses (L22,L23) satisfying the following conditional expressions,

ndLZ+(0.01425dLZ)<2.12, and

dLZ<35.0,

where ndLZ: a refractive index of the lens with reference to d-line, and dLZ: Abbe number of the lens with reference to d-line.

A zoom lens includes a first lens group with a negative refractive power, a second lens group with a positive refractive power, and an aperture stop disposed in and movable with the second lens group. Each of the first lens group and the second lens group moves individually. The zoom lens further includes a doublet lens disposed on a first side of the aperture stop and between the first lens group and the aperture stop, and at most two lenses including at least one aspheric lens are disposed on a second side of the aperture stop.