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.

An optical lens assembly includes: a diaphragm, a zoom lens group, a light deflecting assembly and a compensating lens group sequentially arranged along an optical axis and from an object side to an imaging plane. The optical axis comprises a first optical axis segment between the diaphragm and the light deflecting assembly, and a second optical axis segment between the light deflecting assembly and the compensating lens group. The zoom lens group is located on the first optical axis segment, and the first optical axis segment is different from the second optical axis segment. The optical lens assembly may be incorporated in a camera unit and an electronic device.

A lens system for imaging includes, in order from the object side, a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with positive refractive power, a stop, and a fourth lens group with positive refractive power. The third lens group includes, closest to the image plane side, a cemented lens on the object side of the stop and whose image plane-side surface includes a concave surface on the object side. The fourth lens group includes, closest to the object side, a cemented lens on the image plane side of the stop and whose object-side surface includes a concave surface on the image plane side. A radius of curvature g3er of the object side concave surface and the radius of curvature g4fr of the image plane side concave surface satisfy the following condition: 2.5≤|g4fr/g3er|≤4.0.

A lens system for imaging includes, in order from the object side, a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with positive refractive power, a stop, and a fourth lens group with positive refractive power. The third lens group includes, closest to the image plane side, a cemented lens on the object side of the stop and whose image plane-side surface includes a concave surface on the object side. The fourth lens group includes, closest to the object side, a cemented lens on the image plane side of the stop and whose object-side surface includes a concave surface on the image plane side. A radius of curvature g3er of the object side concave surface and the radius of curvature g4fr of the image plane side concave surface satisfy the following condition: 2.5|g4fr/g3er|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, 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 lens apparatus includes a first lens group, a second lens group, a third lens group and a fourth lens group. The first lens group includes a first lens with negative refractive power and a second lens with negative refractive power. The second lens group includes a third lens with positive refractive power. The third lens group includes a fourth lens with positive refractive power. The fourth lens group includes a fifth lens with negative refractive power, a sixth lens with positive refractive power and a seventh lens with positive refractive power. The lens apparatus satisfies: 2.28<f.sub.LG1/f<0.59, where f is an effective focal length of the lens apparatus, and f.sub.LG1 is an effective focal length of the first lens group.

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 variable magnification optical system (ZL) comprises a first lens group (G1) having negative refractive power, and a rear group (GR) having at least one lens group, the distance between lens groups adjacent to each other changes when the magnification is changed, and the following conditional expression is satisfied. 0.90<TLt/ft<1.50 where TLt is the total length of the variable magnification optical system (ZL) in a telephoto end state, and ft is the focal distance of the variable magnification optical system (ZL) in the telephoto end state.

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.

An optical zoom device for setting an imaging scale of an imaging device, which is configured for imaging an object on an image plane of an image recording device using a microscope objective, comprising an optical element arrangement is disclosed. The optical element arrangement includes an object-side zoom entrance for optical connection to an objective exit, in particular a collimated objective exit, of the microscope objective and includes an image-side zoom exit for optical connection to an image recording entrance of the image recording device. The optical element arrangement includes a tele arrangement designed according to the teleobjective principle, which includes a first optical element group with negative refractive power and a second optical element group with positive refractive power, assigned to the first optical element group for setting the imaging scale, wherein the first optical element group is arranged at the zoom exit and the second optical element group is arranged on the objective side of the first optical element group.