Provided is an optical system including, in order from an object side to an image side, a first lens unit having a negative refractive power, an aperture stop, and a second lens unit having a positive refractive power, in which an average value IR(G2p).sub.AVE of partial dispersion ratios of materials of positive lenses included in the second lens unit and an average value IR(G2n).sub.AVE of partial dispersion ratios of materials of negative lenses included in the second lens unit are appropriately set, provided that BF and F are a backfocus and a focal length of the optical system at a wavelength of 1050 nm, respectively, and a partial dispersion ratio of a material is =(NsNm)/(NsNl), where Ns, Nm, and Nl are refractive indices of the material at wavelengths of 400 nm, 1050 nm, and 1700 nm, respectively.

An orthoscopic, apochromatic lens is suitable for deployment such as on aerial platforms provides distortion less than 0.2% over a full field of view of more than 60 with F# less than 6.5 and focal length greater than 3, and in embodiments greater than 5. Embodiments are apochromatic from 500 to 950 nm to within 7 microns. Embodiments have an overall length of less than 7. The lens includes five optical groups with an aperture stop between the second and third groups. The optical groups have one, one, two, one and one optical element each, as ordered from the object to the image plane, and have positive, negative, positive, positive, and negative optical powers, respectively. Embodiments are telephoto. In embodiments the focal length is temperature invariant within 0.0015 inches from 0 C. to 40 C.

The invention proposed the catadioptric system, which consists of two main components: the first component comprising the two reflective mirrors, in which surface distortion of mirror 1 is parabolic, surface distortion of mirror 2 is aspheric; the second component is a relay consisting of three lenses: lens 1, lens 2, and lens 3 arranged after the medial image plane correspondingly; it plays an important role in fixing the pupil's position to match the position of the cold shield of the sensor and eliminating absolutely the aberration to ensure receiving good quality image at the sensor plane.

A lens compound for connecting to an interchangeable lens mount of a digital camera having a single image sensor, the lens compound including a body; a single mount connecting ring mounted on the body for connecting to the lens mount of the digital camera; at least two lenses of substantially identical focal length mounted in the body; and a different single or multi bandpass filter associated with each of the lenses, allowing the passage of at least one visible band and one non-visible band, selected from the group consisting of near infra-red bands and ultra violet bands of light, through the filters to the sensor; wherein the lenses are of substantially identical field of view and substantially identical image circle at a sensor plane of the image sensor.

A lens including a first lens group and a second lens group is provided. The first lens group is disposed between a magnified side and a minified side. The second lens group is disposed between the first lens group and the minified side. The lens includes six or less lens elements, and at least four of the six or less lens elements are aspheric lenses. A field of view of the lens is in a range between 100 degrees and 165 degrees, and the second lens group has at least one spherical lens.

Embodiments of the present application disclose a camera lens and a camera. The camera lens is provided with a beam splitting device for splitting the incident light into visible light and near-infrared light. The camera lens is further provided with a group of variable magnification lenses and a group of compensation lenses, so that the zoom and aberration correction are achieved. The camera is provided with the camera lens for splitting the visible light and the infrared light. The camera is further provided with a visible light acquisition module for acquiring the visible light exiting from the camera lens and converting the visible light into a color signal and a first brightness signal. The camera is further provided with a near-infrared light acquisition module for acquiring the near-infrared light exiting from the camera lens and converting the near-infrared light into a second brightness signal. The camera is further provided with a fusion module for fusing the color signal, the first brightness signal and the second brightness signal and outputting a fused image. It can be seen that the camera provided by the solution separately processes and then fuses the visible light and the near-infrared light, thereby avoiding color cast during the mixture of them and outputting a color image under a low illumination scene.

This disclosure is directed to systems and methods for acquiring IR light and visible light images. A lens may be configured to operate in at least a first configuration and a second configuration. The lens may have a first filter over a first portion of the lens and a second filter over a second portion of the lens. In the first configuration, a third filter may operate with the lens and the second filter to allow visible light from a first object located beyond a predetermined distance from the lens to pass and be focused on a sensor for image acquisition. In the second configuration, a fourth filter may operate with the lens and the first filter to allow IR light from a second object located within the predetermined distance to pass and be focused on the sensor for image acquisition.

A zoom lens system with a large zoom ratio is disclosed, which operates in a broad spectral range, including visible and infrared spectra. The zoom lens system comprises, in order from the object side to the image side, a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a detection system, wherein zooming from a wide-angle end to a telephoto end is performed by axially moving the second and third lens groups. The system has a relatively long back focal length, and satisfies the following conditions: 0.2<|f2|/(f.sub.W*f.sub.T)<2, 1<f4/|f2|<8, 0.3<|f2|/f3<1.5, where f.sub.W is the system focal length at the wide-angle end, f.sub.T is the system focal length at the telephoto end, (f.sub.W*f.sub.T).sup.1/2 is the geometric mean of the two focal lengths, and fi is the focal length of the i-th lens group.

An infrared optical system includes: a spherical lens unit having an image-forming function as a whole and including one or more spherical lenses that form an image of an incident light beam from a subject; an aperture diaphragm unit that limits transmission of the incident light beam through the spherical lens unit; an aberration correcting plate unit that is disposed at a preceding stage of the spherical lens unit, has at least one aspherical surface, and gives an optical path length difference for compensating an aberration to be generated in the spherical lens unit to the incident light beam; and a lens barrel unit holding the spherical lens unit, the aperture diaphragm unit, and the aberration correcting plate unit.

A dual-band refractive optical system having an eyepiece-type arrangement and configured for mid-wave infrared and long-wave infrared operation. In one example the optical system includes a plurality of lenses, each constructed from a material that is optically transparent in the mid-wave infrared and long-wave infrared spectral bands. The lenses are arranged to receive infrared electromagnetic radiation in an operating waveband that includes at least a portion of the mid-wave infrared and at least a portion of the long-wave infrared spectral bands via a front external aperture stop and to focus the infrared electromagnetic radiation onto a rear image plane, the lenses being positioned between the front external aperture stop and rear image plane. The optical system can further include a corrector plate positioned coincident with the front aperture stop.