A zoom lens system includes a first lens group of negative refractive power and a second lens group of positive refractive power. The first lens group includes a first lens of negative refractive power, and the second lens group is disposed between the first lens group and a reduced side and includes in order from a magnified side to the reduced side a second lens of positive refractive power, a third lens of positive refractive power, a fourth lens of negative refractive power, and a fifth lens of positive refractive power. At least one of the first lens to the fifth lens is an aspherical lens having at least one aspherical surface.

A zoom lens system includes a plurality of lens groups, a lens group of which is moved to perform zooming, wherein a specified lens group of the lens groups is a focusing lens group; a normal photography mode in which focusing is carried out from infinity to a predetermined photographing distance by moving the focusing lens group of the specified lens group; and a shifting mode which shifts from the normal photography mode to a macro photography mode by moving a lens element of the specified lens group other than the focusing lens group when focusing on an object at a photographing distance that is shorter than the predetermined photographing distance. When the zoom lens system is in the macro photography mode, focusing is carried out from the predetermined photographing distance to a minimum photographing distance by moving the focusing lens group.

In an optical system including, in order from an object side to an image side: a front unit (LF) having a negative refractive power; an aperture stop; and a rear unit (LR) having a positive refractive power, the front unit (LF) includes a meniscus-shaped negative lens (g1) closest to the object side, and a focal length (fw) of the entire optical system, a focal length (fg1) of the meniscus-shaped negative lens (g1), and a curvature radius (R2) of a lens surface on the image side of the meniscus-shaped negative lens (g1) are appropriately set.

An optical system includes a first optical system configured to form an optical image of an object in a first imaging area, and a second optical system disposed in parallel with the first optical system and configured to form an optical image of the object in a second imaging area. Each of the first optical system and the second optical system includes an aperture stop fixed in an optical axis direction relative to a position of an image plane, and a lens unit disposed on an image plane side of the aperture stop and movable in the optical axis direction. A predetermined inequality is satisfied.

An imaging lens consists of, in order from the object side, a front group, a stop, and a rear group, wherein the front group includes, in order from the most-object side, a positive first lens, a negative second lens, a negative third lens which are adjacently disposed, and further includes a final lens of the front group adjacent to the stop, with the surface toward the stop being convex toward the image side, the rear group includes, in order from the image side, two sets of cemented lenses having positive refractive powers, which are adjacently disposed, the object-side cemented lens of the two sets of cemented lenses is formed by cementing a positive lens and a negative meniscus lens together, and the image-side cemented lens is formed by cementing a negative meniscus lens and a positive lens together.

The present application provides a micromechanical (MEMS) based zoom lens system, for use in miniature device applications, such as miniature electronic imaging devices. The MEMS-based zoom lens system comprises at least four optical elements, or two Alvarez or Lohmann lenses, that are configured for passage of optical signals therethrough along an optical signal path. Each optical element is MEMS-driven and displaceable in a direction substantially transverse to the optical signal path. In use, the transverse displacement of the optical elements vary an overall focal length of the MEMS zoom lens system such as to provide an optical zoom function. A method of manufacturing a MEMS zoom lens system is also provided in a further aspect.

At least one embodiment of an optical system includes, in order from an object side to an image side, a front unit including a plurality of lenses, an aperture stop, and a rear unit having a positive refractive power. In at least one embodiment, four negative lenses are consecutively arranged from a side of the front unit closest to the object side, and a focal length of the front unit and a focal length of the rear unit are appropriately set.

In an optical system in which a focal length of an entire system is shorter than a back focus, an image stabilizing lens unit, is at a position adjacent to an aperture on an image side and a cemented lens obtained by cementing a positive lens and a negative lens is on an object side of the aperture diaphragm, and the focal length of the entire system, a focal length of the image stabilizing lens unit, a focal length of the cemented lens, a distance on the optical axis from the aperture to a lens surface on the object side of the image stabilizing lens unit, and a distance on the optical axis from a first lens surface on a side closest to an object to a final lens surface on a side closest to an image when an infinite-distance object is brought into focus are set.

A zoom lens system includes a first lens group of negative refractive power and a second lens group of positive refractive power. The first lens group includes a first lens of negative refractive power, and the second lens group is disposed between the first lens group and a reduced side and includes in order from a magnified side to the reduced side a second lens of positive refractive power, a third lens of positive refractive power, a fourth lens of negative refractive power, and a fifth lens of positive refractive power. At least one of the first lens to the fifth lens is an aspherical lens having at least one aspherical surface.

A zoom lens including a first lens group and a second lens group is provided. The first lens group having a negative refractive power is disposed between an object side and an image side and includes a first lens having a negative refractive power. The second lens group having a positive refractive power is disposed between the first lens group and the image side and includes a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object side to the image side. Refractive powers of the second lens, the third lens, the fourth lens and the fifth lens are positive, positive, negative and positive in sequence, wherein the first lens has a surface facing the object side, a radius of curvature of the surface is R1, and |R1|>700 mm.