A wide attachment which is detachably attached to an object side of a lens apparatus and in which a focal length of the lens apparatus is shifted to a short focal length side. The wide attachment is formed of a single meniscus lens having a negative refractive power. The lens has an aspherical surface. The following conditional expressions are satisfied: −5.2<−(r1+r2)/(r1−r2)<−1.3, and 1.50<nd<1.53, where r1 represents a curvature radius of a surface on an object side of the lens, r2 represents a curvature radius of a surface on an image side of the lens, and nd represents a refractive index of a material constituting the lens with respect to d-line, wherein a curvature radius of the aspherical surface is defined as a curvature radius of a spherical surface passing through a lens vertex and a maximum effective diameter of the aspherical surface.

A wide attachment which is detachably attached to an object side of a lens apparatus and in which a focal length of the lens apparatus is shifted to a short focal length side. The wide attachment is formed of a single meniscus lens having a negative refractive power. The lens has an aspherical surface. The following conditional expressions are satisfied: −5.2<−(r1+r2)/(r1−r2)<−1.3, and 1.50<nd<1.53, where r1 represents a curvature radius of a surface on an object side of the lens, r2 represents a curvature radius of a surface on an image side of the lens, and nd represents a refractive index of a material constituting the lens with respect to d-line, wherein a curvature radius of the aspherical surface is defined as a curvature radius of a spherical surface passing through a lens vertex and a maximum effective diameter of the aspherical surface.

A converter lens has negative refractive power, and is disposed on an image side of a master lens so that a focal length of an entire system becomes greater than a focal length of the master lens alone. The converter lens includes a first lens element closest to an object and a second lens element next to an image side of the first lens element with a space between the first lens element and the second lens element. A focal length of the converter lens, a focal length of an air lens formed by the first lens element and the second lens element, the shape of an image-side lens surface of the first lens element, and the shape of an object-side lens surface of the second lens element are determined as appropriate.

A driving module configured for driving a teleconverter lens assembly to move up and down with precision includes a mounting base, a driving assembly connected with the mounting base, and an optical grating sensor. The driving assembly includes a linear motor adapted to be fixedly connected with the teleconverter lens assembly and configured to drive the teleconverter lens assembly to move, and an air cylinder configured to support the teleconverter lens assembly. The optical grating sensor is electrically connected with the linear motor and configured to detect and feedback a position of the teleconverter lens assembly driven by the linear motor in real time. A focusing mechanism including the driving module is also disclosed.

A driving module configured for driving a teleconverter lens assembly to move up and down with precision includes a mounting base, a driving assembly connected with the mounting base, and an optical grating sensor. The driving assembly includes a linear motor adapted to be fixedly connected with the teleconverter lens assembly and configured to drive the teleconverter lens assembly to move, and an air cylinder configured to support the teleconverter lens assembly. The optical grating sensor is electrically connected with the linear motor and configured to detect and feedback a position of the teleconverter lens assembly driven by the linear motor in real time. A focusing mechanism including the driving module is also disclosed.

A converter lens has negative refractive power, and is disposed on an image side of a master lens so that a focal length of an entire system becomes greater than a focal length of the master lens alone. The converter lens includes a first lens element closest to an object and a second lens element next to an image side of the first lens element with a space between the first lens element and the second lens element. A focal length of the converter lens, a focal length of an air lens formed by the first lens element and the second lens element, the shape of an image-side lens surface of the first lens element, and the shape of an object-side lens surface of the second lens element are determined as appropriate.

This disclosure describes an afocal attachment that allows for alteration of received electromagnetic radiation (or “light”) prior to entry into the telescope. For example, a rifle scope may have a base magnification of 2×, and the afocal attachment may allow magnification of a received image at levels ranging from 2× to 4×. In this example, the entire telescope system with the afocal attachment installed will have an overall magnification of 4× to 8×. In another example, the magnification of the telescope can be increased, transforming a telescope with a 4× magnification into a telescope with a higher effective magnification. In some instances the afocal attachment's optical axis can be configured to permit independent adjustment, allowing for easy removal and reinstallation of the afocal attachment without a need to re-adjust the telescope itself.

This disclosure describes an afocal attachment that allows for alteration of received electromagnetic radiation (or “light”) prior to entry into the telescope. For example, a rifle scope may have a base magnification of 2×, and the afocal attachment may allow magnification of a received image at levels ranging from 2× to 4×. In this example, the entire telescope system with the afocal attachment installed will have an overall magnification of 4× to 8×. In another example, the magnification of the telescope can be increased, transforming a telescope with a 4× magnification into a telescope with a higher effective magnification. In some instances the afocal attachment's optical axis can be configured to permit independent adjustment, allowing for easy removal and reinstallation of the afocal attachment without a need to re-adjust the telescope itself.

A lens accessory (1) is detachably attached to a lens barrel (2), and includes a first holder (104) and a second holder (105) for holding the lens barrel, an operation member (102) that moves at least one holder of the first holder and the second holder between a first position and a second position, and a biasing mechanism (110) that applies a biasing force to the at least one holder so as to hold the lens barrel, the biasing mechanism includes a first biasing member and a moving member that moves the at least one holder from the first position to the second position according to an operation of the operation member via the first biasing member, and when the at least one holder contacts the lens barrel, the first biasing member is displaced by the moving member.

A lens accessory (1) is detachably attached to a lens barrel (2), and includes a first holder (104) and a second holder (105) for holding the lens barrel, an operation member (102) that moves at least one holder of the first holder and the second holder between a first position and a second position, and a biasing mechanism (110) that applies a biasing force to the at least one holder so as to hold the lens barrel, the biasing mechanism includes a first biasing member and a moving member that moves the at least one holder from the first position to the second position according to an operation of the operation member via the first biasing member, and when the at least one holder contacts the lens barrel, the first biasing member is displaced by the moving member.