An extender lens changes a focal length of an entire lens system after replacement to a longer focal length side than a focal length of a master lens by replacing a part of the master lens with the extender lens. The extender lens consists of, in order from an object side to an image side, a first lens group, and a negative second lens group. The first lens group is a lens group that has a positive refractive power as a whole and has a shortest focal length among lens groups consisting of one lens component or a plurality of consecutively arranged lens components. The extender lens satisfies a predetermined conditional expression.

A reflective beam former for changing a diameter of a collimated light beam. A first mirror surface of a first curvature type, a second mirror surface and a third mirror surface are in a beam path; the shapes of the surfaces cause a collimated light beam entering the beam former via a first or third mirror surface to leave via the third or first mirror surface, respectively. The beam former includes several third, curved mirror surfaces of a second, different curvature type, one type being convex, the other concave. The second mirror surface is a plane mirror surface with an axis perpendicular to the plane mirror surface, and is in the beam path between the first and one selected from the several third mirror surfaces such that the surfaces are confocal to each other. The beam former includes a selector for selecting one of the several third curved mirror surfaces.

A reflective beam former for changing a diameter of a collimated light beam. A first mirror surface of a first curvature type, a second mirror surface and a third mirror surface are in a beam path; the shapes of the surfaces cause a collimated light beam entering the beam former via a first or third mirror surface to leave via the third or first mirror surface, respectively. The beam former includes several third, curved mirror surfaces of a second, different curvature type, one type being convex, the other concave. The second mirror surface is a plane mirror surface with an axis perpendicular to the plane mirror surface, and is in the beam path between the first and one selected from the several third mirror surfaces such that the surfaces are confocal to each other. The beam former includes a selector for selecting one of the several third curved mirror surfaces.

A camera module disclosed in an embodiment of the invention includes: a first holder having a plurality of first lens groups arranged in a first direction; a second holder having a plurality of second lens groups arranged in the first direction; and a first driving means for moving the first holder having the plurality of first lens groups in the optical axis direction, wherein each of the plurality of first lens groups may include a plurality of lenses, and each of the plurality of second lens groups may include a plurality of lenses.

An optical apparatus that is capable of improving impact resistance thereof. A holding member holding the optical element is movably attached to a first member so that the optical element is movable between an entering position where the optical element enters into an optical path and a retracted position where the optical element is retracted from the optical path. The first member is movably attached to a second member. A driving member engages with the holding member and drives the holding member. A regulation member regulates a moving amount of the first member with respect to the second member. The regulation member is arranged so that a distance from an engagement position of the holding member and the driving member at the entering position to the regulation member is longer than a distance from the engagement position at the retracted position to the regulation member.

An optical apparatus that is capable of improving impact resistance thereof. A holding member holding the optical element is movably attached to a first member so that the optical element is movable between an entering position where the optical element enters into an optical path and a retracted position where the optical element is retracted from the optical path. The first member is movably attached to a second member. A driving member engages with the holding member and drives the holding member. A regulation member regulates a moving amount of the first member with respect to the second member. The regulation member is arranged so that a distance from an engagement position of the holding member and the driving member at the entering position to the regulation member is longer than a distance from the engagement position at the retracted position to the regulation member.

An imaging lens including a first lens group, a second lens group, and an aperture stop is provided. The first lens group is disposed between an object side and an image side. The second lens group is disposed between the first lens group and the image side. The aperture stop is disposed between the first lens group and the second lens group. The imaging lens includes at least three cemented lenses, each of the cemented lenses includes at least one lens having non-zero refractive power, and at least one lens of each of the cemented lenses has an Abbe number greater than 80.

A rear conversion lens, which may include a plurality of lenses may be disposed at a side of master lenses facing an image side for varying a focal length, and may include: a first lens having a positive refractive power; a second lens having a biconcave shape; a third lens having a positive refractive power; a fourth lens having a positive refractive power; and a fifth lens having a negative refractive power. The first to fifth lenses may be sequentially arranged in a direction from an object side to the image side.

An illustrative example method of making a camera includes assembling a plurality of lens elements, a sensor, and a housing to establish an assembly with each of the lens elements and the sensor at least partially in the housing. The assembly is then situated adjacent a circuit board substrate. At least the sensor is secured to the circuit board substrate using surface mount technology (SMT) and the assembly becomes fixed relative to the circuit board substrate.

There is provided a piezoelectric material not containing any lead component, having stable piezoelectric characteristics in an operating temperature range, a high mechanical quality factor, and satisfactory piezoelectric characteristics. The piezoelectric material includes a main component containing a perovskite-type metal oxide that can be expressed using the following general formula (1), and subcomponents containing Mn, Li, and Bi. When the metal oxide is 100 parts by weight, the content of Mn on a metal basis is not less than 0.04 parts by weight and is not greater than 0.36 parts by weight, content α of Li on a metal basis is not less than 0.0013 parts by weight and is not greater than 0.0280 parts by weight, and content β of Bi on a metal basis is not less than 0.042 parts by weight and is not greater than 0.850 parts by weight
(Ba.sub.1-xCa.sub.x).sub.a(Ti.sub.1-y-zZr.sub.ySn.sub.z)O.sub.3  (1)
(in the formula (1), 0.09≦x≦0.30, 0.074<y≦0.085, 0≦z≦0.02, and 0.986≦a≦1.02).