The present disclosure discloses an optical imaging lens assembly. The optical imaging lens assembly comprises: an imaging lens group, composed of a first lens, a second lens, a third lens, a fourth lens and a fifth lens that are sequentially arranged along an optical axis from an object side to an image side; a fourth spacing elements; and a lens barrel, forming an accommodation space in which the imaging lens group and the fourth spacing elements are accommodated. The lens barrel comprises an object-end surface close to the object side, an image-end surface close to the image side, an inner wall and an outer wall.

A high magnification MWIR continuous zoom optical system is described herein that consists of the following components: a front detachable extender group, a fixed group for focusing incoming radiation, three moving groups for zooming and generating an intermediate image and a relay group. The mentioned optical system has the ability to work with MWIR radiation (3-5 μm) and generate a thermal image from the gathered radiation. The system also has the ability to zoom continuously in a wide variable focal length range with a high magnification ratio of 20×. With the use of a cooled detector, the combined system allows its user to be able to receive high quality thermal images in all FOV configurations.

The present embodiment discloses an interchangeable lens that can be detachably attached to an apparatus body having an image forming surface on which an image is formed, and the interchangeable lens has a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side. The interchangeable lens includes a focus lens group that can move along an optical axis to adjust a focus at the magnification conjugate point and a flange back distance correction lens group that can move along the optical axis to correct an error in a flange back distance of the interchangeable lens with respect to the image forming surface.

A zoom optical system comprises, in order from an object: a front lens group (GFS) having a positive refractive power; an M1 lens group (GM1) having a negative refractive power; an M2 lens group (GM2) having a positive refractive power; an RN lens group (GRN) having a negative refractive power; and a subsequent lens group (GRS). Upon zooming, the distance between the front lens group (GFS) and the M1 lens group (GM1) changes, the distance between the M1 lens group (GM1) and the M2 lens group (GM2) changes, and the distance between the M2 lens group (GM2) and the RN lens group (GRN) changes. Upon focusing from an infinite distant object to a short distant object, the RN lens group (GRN) moves.

The zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, a negative fifth lens group, and a positive sixth lens group in order from an object side. All distances between adjacent lens groups change during zooming. The first lens group consists of a negative lens, a positive lens, and a positive lens in order from the object side. Only the fourth lens group moves to an image side during focusing from a long range to a short range. Conditional Expression is related to lateral magnification of the fourth lens group and a lateral magnification of the sixth lens group is satisfied.

The zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, a negative fifth lens group, and a positive sixth lens group in order from an object side. All distances between adjacent lens groups change during zooming. The first lens group consists of a negative lens, a positive lens, and a positive lens in order from the object side. Only the fourth lens group moves to an image side during focusing from a long range to a short range. Conditional Expression is related to lateral magnification of the fourth lens group and a lateral magnification of the sixth lens group is satisfied.

Pop-out lens systems for compact digital cameras, comprising an image sensor and a lens with a field of view FOV>60 deg and having i lens elements L1-Li starting with L1 from an object side toward an image side, each lens element Li having a respective focal length f.sub.i, the lens elements divided into two lens groups G1 and G2 separated by a big gap (BG), the lens having a pop-out total track length TTL<20 mm in a pop-out state and a collapsed total track length c-TTL in a collapsed state, wherein BG>0.25×TTL, wherein either G1 can move relative to G2 and to the image sensor for focusing or G1 and G2 can move together relative to the image sensor for focusing, and wherein a ratio c-TTL/TTL<0.7.

A projection system has a zooming function and is configured that light rays from a telecentric system enter. The projection system is formed of seven lens groups. The first and seventh lens groups are fixed when the projection magnification is changed, and the second, third, fourth, fifth, and the sixth lens groups move along the optical axis when the projection magnification is changed. The second lens group is formed of one positive lens. The third lens group is formed of one positive lens. The fourth lens group is formed of one or two positive lenses and one negative lens having the center of curvature located at the magnifying side. The fifth lens group is formed of one negative lens having a magnifying-side aspheric surface and a demagnifying-side aspheric surface with each of the surfaces having the center of curvature located at the demagnifying side.

A lens barrel according to the present disclosure includes a booster transformer that is arranged on an inner circumference side of a cam barrel and constitutes a power supply for an actuator. The booster transformer is arranged on a side surface of a barrel. The booster transformer is configured to move in an optical axis direction together with the barrel in accordance with rotation of the cam barrel.

A zoom lens satisfies Conditional Expression (1) as follows:
−20<Twt/Twm<1,  (1)
Twt is a moving amount of the second lens group during zooming from the short focal-length end to the long focal-length end, a moving amount to the object side being indicated by a positive sign, a moving amount to an image side being indicated by a negative sign, and
Twm is a moving amount of the second lens group during zooming from the short focal-length end to an intermediate focal length, a moving amount to the image side being indicated by a negative sign,
the intermediate focal length being expressed by fm=(fw.Math.ft).sup.1/2, where fw is a focal length of a whole system at the short focal-length end, and ft is a focal length of the whole system at the long focal-length end.