Folded Tele cameras comprising an optical path folding element (OPFE) for folding a first optical path OP1 to a second optical path OP2, a lens including N=8 lens elements, the lens being divided into three lens groups numbered, in order from an object side of the lens, G1, G2 and G3, and an image sensor, wherein G1 and G3 are included in a single G13 carrier, wherein G2 is included in a G2 carrier, wherein both the G13 carrier and the G2 carrier include rails for defining the position of G2 relative to G13, wherein the Tele camera is configured to change a zoom factor continuously between a minimum zoom factor ZF.sub.MIN and a maximum zoom factor ZF.sub.MAX by moving the G2 carrier relative to the G13 carrier and by moving the G13 carrier relative to the image sensor, and wherein an effective focal length (EFL) is 7.5 mm<EFL<50 mm. The G2 carrier may be positioned by a lens transporter within the G13 carrier at a particular zoom factor to form a lens pair to enable optical investigation and/or transporting of the lens pair.

The present disclosure is directed to an optical system internally having an intermediate imaging position MI that is conjugate with both of a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, the optical system including: a first positive lens group GP1 including a plurality of lens elements and positioned on the magnification side with respect to the intermediate imaging position; a second positive lens group GP2 including a plurality of lens elements and positioned between the first positive lens group GP1 and the intermediate imaging position Ml; and a negative lens group GN including a plurality of lens elements and positioned on the reduction side with respect to the intermediate imaging position MI, wherein, during focusing, the first positive lens group GP1 and the negative lens group GN move in an optical axis direction, and the second positive lens group GP2 is stationary.

A zoom optical system (ZL) comprises: a first lens group (G1) disposed closest to an object and having a positive refractive power; an aperture stop (S) disposed closer to an image than the first lens group (G1); a positive lens component disposed so as to oppose the image side of the aperture stop (S); and a lens group (G3) having the positive lens component, wherein a distance between the first lens group (G1) and the lens group (G3) having the positive lens component changes during zooming, at least one lens surface of the positive lens component has an aspherical surface, and the following conditional expression,

0.40<fp/fGp<3.60

is satisfied,
where fp: a focal length of the positive lens component, and fGp: a focal length of the lens group (G3) having the positive lens component.

A zoom optical system includes a positive first lens group, a negative second lens group disposed on an image side of the first lens group, a positive third lens group disposed on an image side of the second lens group, a negative fourth lens group disposed on an image side of the third lens group, and a final lens group disposed on an image side of the fourth lens group and closest to an image. During zooming, distances between lens groups change, and the first lens group moves along an optical axis. A negative focusing lens group is provided, and the final lens group is disposed on an image side of the focusing lens group. A negative vibration proof group of the second lens group may include, in order from an object, a negative lens, an air gap and a cemented lens of a negative lens and a positive lens. The final lens group may have negative refractive power.

An optical system according to the present invention is an optical system consisting of a front lens group having a positive or negative refractive power, an aperture stop, and a rear lens group having a positive or negative refractive power that are placed in order from an object side to an image side. In the optical system, relationships between a distance on an optical axis between a negative lens having the strongest refractive power in the rear lens group and a positive lens placed on the image side of the negative lens, an opening angle of the positive lens, a back focus of the optical system, and a focal length of the optical system are appropriately determined.

Folded Tele cameras comprising an optical path folding element (OPFE) for folding a first optical path OP1 to a second optical path OP2, a lens including N=8 lens elements, the lens being divided into three lens groups numbered, in order from an object side of the lens, G1, G2 and G3, and an image sensor, wherein G1 and G3 are included in a single G13 carrier, wherein G2 is included in a G2 carrier, wherein both the G13 carrier and the G2 carrier include rails for defining the position of G2 relative to G13, wherein the Tele camera is configured to change a zoom factor continuously between a minimum zoom factor ZF.sub.MIN and a maximum zoom factor ZF.sub.MAX by moving the G2 carrier relative to the G13 carrier and by moving the G13 carrier relative to the image sensor, and wherein an effective focal length (EFL) is 7.5 mm<EFL<50 mm. The G2 carrier may be positioned by a lens transporter within the G13 carrier at a particular zoom factor to form a lens pair to enable optical investigation and/or transporting of the lens pair.

A variable-magnification optical system (ZL) comprises: a first lens group (G1) having a positive refractive power; and a rear group (GR) including a plurality of lens groups. When changing the magnification, the gap between each adjacent pair of lens groups changes. The plurality of lens groups in the rear group (GR) include a second lens group (G2) having a positive refractive power and disposed nearest to the object side in the rear group (GR). The variable-magnification optical system (ZL) satisfies the following conditional expression: 0.15<f2/f1<0.80, where f1 is the focal length of the first lens group (G1), and f2 is the focal length of the second lens group (G2).

Folded Tele cameras comprising an optical path folding element (OPFE) for folding a first optical path OP1 to a second optical path OP2, a lens including N=8 lens elements, the lens being divided into three lens groups numbered, in order from an object side of the lens, G1, G2 and G3, and an image sensor, wherein G1 and G3 are included in a single G13 carrier, wherein G2 is included in a G2 carrier, wherein both the G13 carrier and the G2 carrier include rails for defining the position of G2 relative to G13, wherein the Tele camera is configured to change a zoom factor continuously between a minimum zoom factor ZF.sub.MIN and a maximum zoom factor ZF.sub.MAX by moving the G2 carrier relative to the G13 carrier and by moving the G13 carrier relative to the image sensor, and wherein an effective focal length (EFL) is 7.5 mm<EFL<50 mm. The G2 carrier may be positioned by a lens transporter within the G13 carrier at a particular zoom factor to form a lens pair to enable optical investigation and/or transporting of the lens pair.

An observation optical system has an objective system and an eyepiece system in the order from the object side. The objective system includes, in the order from the object side, a first group having a positive power, a second group having a positive power, and a third group having a negative power. The objective system has an inverting optical system. The eyepiece system includes, in the order from the object side, a fourth group having a positive power and a fifth group having a positive power. The third group and the fourth group move in directions separating from each other along an optical axis to thereby perform variable power from a low magnification to a high magnification, and also the following conditional expression is satisfied:
0.28<HL/f0.55 (1).

An optical system includes, in order from object side, a first unit, a stop, a second unit, and a third unit. The first and second units are moved toward object side to increase respective intervals from the third unit for focusing from infinity to proximity. The first unit includes a negative lens and a positive lens arranged adjacent and on image side of the negative lens. The third unit consists of a positive lens (G3P) and a negative lens (G3N) arranged adjacent and on image side of the positive lens (G3P). An equivalent air length from a lens surface on image side of the negative lens (G3N) to an image plane when focused at infinity, and a distance on an optical axis from a lens surface on object side of a lens (G1F) arranged closest to object side, to the image plane when focused at infinity are appropriately set.