A variable-power optical system (ZL) comprises a first lens group (G1) having a negative refractive power and a succeeding lens group (GR), which are disposed on an optical axis in that order from the object side. When varying magnification from wide angle to telephoto, the space between the adjacent lens groups changes. The succeeding lens group (GR) comprises: a first focusing lens group (G3) having a positive refractive power; and a second focusing lens group (G5) having a positive refractive power. When focusing from infinity to a proximate distance, the first focusing lens group (G3) moves toward the object side, and the second focusing lens group (G5) moves toward the image side.

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 unit having a positive refractive power as a whole. A distance between the first lens unit and the rear unit is changed during zooming. The rear unit includes a subunit that is moved in a direction having a component of a direction orthogonal to an optical axis during image stabilization. The first lens unit includes, in order from the object side to the image side, three or more negative lenses. A predetermined condition is satisfied.

An optical system includes a first optical subsystem disposed on an enlargement side and a second optical subsystem disposed on a reduction side with an intermediate image in between. The first optical subsystem includes: a first lens group that is disposed on the enlargement side of a first stop with a first distance, in which other lenses could be disposed but no other lenses are disposed, and is provided on the enlargement side with a first component with negative refractive power; and a second lens group that has positive refractive power, is disposed on the reduction side of the first stop with a second distance, in which other lenses could be disposed but no lenses are disposed, and forms the intermediate image so as to be adjacent on a reduction side of the second lens group and so as to be tilted toward the enlargement side.

The present disclosure provides an optical projection system and an electronic device. The optical projection system includes from a zoom-in side to a zoom-out side: a first lens group and a second lens group sequentially arranged along an optical axis, and the second lens group has a positive focal power; the first lens group comprises a negative lens group and a positive lens group, the positive lens group is located closer to the zoom-out side than the negative lens group, the negative lens group comprises at least one lens with a negative focal power, and the positive lens group comprises at least one lens with a positive focal power; the negative lens group and the positive lens group are provided with a first air gap greater than 9.5 mm therebetween.

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>0.25TTL, 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 zoom lens includes a plurality of lens units. Each distance between adjacent lens units changes during zooming. At least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion. A predetermined inequality is satisfied.

Provided are an optical element and an image display apparatus that display an aerial image, in which the total volume of the apparatus is small, a reduction in size can realized, and a scenery can be recognized. The optical element includes: a light guide element including a light guide plate, an incidence diffraction element, and an emission diffraction element, the incidence diffraction element being disposed on a main surface of the light guide plate and the emission diffraction element being disposed on the main surface of the light guide plate; and a positive lens that is disposed at a position overlapping the emission diffraction element in a view from a direction perpendicular to the main surface of the light guide plate, in which the incidence diffraction element diffracts incident light such that the diffracted light is incident into the light guide plate, the emission diffraction element emits light propagating in the light guide plate from the light guide plate, and the positive lens collects the light that is emitted from the light guide plate by the emission diffraction element.

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 imaging optical system includes a plurality of lens units. Each distance between adjacent lens units among the plurality of lens units changes during zooming. The plurality of lens units include a first lens unit with negative refractive power and a second lens unit with positive refractive power disposed closer to an image plane than the first lens unit, and a first transmissive reflective surface and a second transmissive reflective surface disposed closer to the image plane than the first transmissive reflective surface.

A zoom lens consists of, 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 a rear group including one or more lens units. Each distance between adjacent lens units changes during zooming. The rear group includes a focus lens unit having a positive refractive power that moves from the image side to the object side during focusing from an infinite distance object to a close distance object. A lens closest to an object in the focus lens unit has a shape with a concave surface on the object side. The following inequalities are satisfied.

[00001]$1.2<\mathrm{fLP}/\mathrm{fL}2<3.2$$-3.<\mathrm{fL}1/\mathrm{fL}2<-0.85$

fLP represents a focal length of the focus lens unit, fL1 represents a focal length of the first lens unit, and fL2 represents a focal length of the second lens unit.