Abstract: A camera optical lens is provided, including from an object side to an image side: a first lens; a second lens having negative refractive power; a third lens; a fourth lens; a fifth lens; a sixth lens; a seventh lens; an eighth lens; and a ninth lens, wherein the camera optical lens satisfies the following conditions: 2.00?f1/f?5.50; and 1.50?d15/d16?9.00, where f denotes a focal length of the camera optical lens; f1 denotes a focal length of the first lens; d15 denotes an on-axis thickness of the eighth lens; and d16 denotes an on-axis distance from an image side surface of the eighth lens to an object side surface of the ninth lens. The above camera optical lens can meet design requirements for large aperture, wide-angle and ultra-thinness, while maintaining good imaging quality.

Abstract: A camera assembly includes an image sensor having a field of view corresponding to a scene, an infrared (IR) illuminator configured to selectively illuminate the scene, and a single-piece cover element positioned in front of the image sensor and the IR illuminator such that light from the IR illuminator is directed through the cover element along a first light path and light from the scene passes through the cover element along a second light path prior to entering the image sensor, the cover element including a first portion between the first light path and the second light path, the first portion being substantially opaque to IR and/or visible light.

Abstract: A window film including at least a first adhesive layer containing a weathering agent, a barrier layer, a second adhesive layer, and a light control layer in this order.

Abstract: The present invention relates to devices and methods of use thereof for real time blood flow measurements of skin. In one embodiment, the device is a compact laser speckle imaging, or LSI, system that is integrated with a dermatoscope. In another embodiment, the device allows the user to diagnose a disease or condition in an individual, or as part of an overall treatment regimen.

Abstract: A correction lens is used in an optical system in which a light-transmissive cover member having radii of curvature different from each other in a predetermined first direction and a second direction perpendicular to the first direction is disposed on an object side. Radii of curvature of an image-side surface of the correction lens are different in the first direction and the second direction, and satisfy a predetermined condition.

Abstract: An infrared (IR) digital lens (IR Objective) for an optical microscope is disclosed which includes a body, configured to be mounted to an objective interface of an optical microscope, an IR camera disposed in the body, the IR camera configured to receive light in the range of IR and capture images from a specimen disposed under the body without the need to move the specimen from the optical microscope.

Abstract: An inspection system and a method for inspection an object. The method may include acquiring a defocused image of an area of an object, and processing the defocused image of the area to find a phase shift between optical paths associated with certain proximate points of the area. The phase shift may be indicative of a defect. The acquiring of the defocused image may include illuminating the area with a radiation beam that may be spatially coherent and collimated when impinging on the area. The illuminating may include passing the radiation beam through an aperture that may be defined by an aperture stop that may be positioned within an aperture stop plane. The size of the aperture may be a fraction of a size of the aperture stop.

Abstract: The various implementations described herein include methods, devices, and systems for illuminating and capturing scenes. In one aspect, a video camera assembly includes: (1) an image sensor having a field of view corresponding to a scene; (2) infrared illuminators to selectively illuminate the scene; and (3) a single-piece cover positioned in front of the image sensor and the illuminators such that light from the illuminators is directed through the cover and light from the scene passes through the cover prior to entering the image sensor, including: (a) a first portion corresponding to the image sensor and substantially transparent to visible light and IR light; (b) a second portion corresponding to the one or more IR illuminators and coated to be substantially transparent to IR light; and (c) a third portion between the first portion and the second portion and coated to be substantially opaque to IR and visible light.

Abstract: A remote switch device for an arm-mounted electrical lighting accessory, such as a flashlight, may be securable to a finger of a user. The switch device can include a remote control unit in electrical contact with the end of a flexible cable. The remote control unit can include an integral finger mount for attachment to a finger of the user. The flexible cable can include one end in electrical contact with the remote control unit and a second end in electrical contact with a first connector adapted for being electrically connected to a complementary second connector on the arm-mounted electrical lighting accessory.

Abstract: A surgical system that includes a surgical glove configured to be removably attached to a human hand is disclosed. The surgical glove can include a first surgical instrument attached to the surgical glove, where the first surgical instrument is nonremoveably, integrally attached to the surgical glove during the formation of the surgical glove, and where the first surgical instrument is coupled to a finger of the surgical glove; a first switch attached to the surgical glove for controlling the first surgical support system; and a first actuating element attached to a thumb of the surgical glove. The first actuating element can be a discrete element. The first switch can be actuated when the first actuating element is placed in close proximity to the first switch, and a thumb of said surgical glove can be free of surgical support systems.

Abstract: A basketball shooting training device employs a housing for retaining an optical projection device and one or more straps for facilitating a secure connection to the user. In various embodiments, the optical projection device is configured to emit a light beam, which facilitates prompt and accurate feedback for a user employing the device.

Abstract: Disclosed is an infrared reflective film (100) configured by disposing an infrared ray reflective layer (20) and a transparent protective layer (30) on a transparent film backing (10) in this order. The infrared ray reflective layer (20) comprises: a first metal oxide layer (21); a metal layer (25) comprising a primary component consisting of silver; and a second metal oxide layer (22) comprised of a composite metal oxide containing zinc oxide and tin oxide, which are arranged in this order from the side of the transparent film backing (10). The transparent protective layer (30) lies in direct contact with the second metal oxide layer (22). The transparent protective layer (30) has a thickness of 30 nm to 150 nm, and is preferably an organic layer having a cross-linked structure derived from an ester compound having an acidic group and a polymerizable functional group in the same molecule.

Abstract: A basketball shooting training device employs a housing for retaining an optical projection device and one or more straps for facilitating a secure connection to the user. In various embodiments, the optical projection device is configured to emit a light beam, which facilitates prompt and accurate feedback for a user employing the device.

Abstract: The zoom lens comprises five or more groups of lens pieces, namely, the foremost or first lens group of positive refractive power located the closest to an object, the succeeding second lens group of negative refractive power, the third lens group of positive refractive power, the fourth lens group of positive refractive power, and the fifth lens group all arranged in this order, and if any, the rearmost lens group(s) closer to the imaging plane than the fifth lens group. The zoom lens meets requirements as defined in the conditional expression regarding a combined magnification of the fifth lens group and, if any, the rearmost lens group(s) closer to the imaging plane than the fifth lens group while the zoom lens is taking a telephoto position.

Abstract: An optical arrangement of lenses configured for use with an ultra wide band optical sensor is provided herein. The optical arrangement is associated with a back focal plane and further includes a first, a second, a third, a fourth, a fifth, and a sixth lens ordered from first to sixth along a common optical axis such that the first lens is farthest from the back focal plane and the sixth lens is closest to the back focal plane, wherein the first and the second lenses are made of zinc sulfide, the third and the sixth lenses are made of barium fluoride, the fourth lens is made of magnesium oxide, and the fifth lens is made of calcium fluoride, and wherein the lenses are selected to transfer any light within a wavelength range that contains 0.42 ?m to 3.6 ?m.

Abstract: An interchangeable lens including a fitting unit that can be fitted to and removed from a camera body; an imaging optical system that has an aperture, and whose focal length is variable over a range from a first focal length to a second focal length; and an MTF characteristic transmission unit that transmits MTF characteristic data specifying MTF characteristics of the imaging optical system to the camera body.

Abstract: A zoom lens includes sequentially from an object side a first lens group having a negative refractive power; an aberture stop; and a second lens group having a positive refractive power. The second lens group is moved along an optical axis toward the object side to zoom from a wide angle edge to a telephoto edge. The first lens group is moved along the optical axis toward en image side to correct image plane variation accompanying zooming. The second lens group includes sequentially from the object side, a positive lens having at least one aspheric surface, and a cemented lens configured by a negative lens, a positive lens, and a negative lens. The zoom lens satisfies a conditional expression (1) 1.8<D2/Z<2.3, where D2 indicates an amount of movement of the second lens group, accompanying zooming from the wide angle edge to the telephoto edge, and Z indicates a zoom ratio.

Abstract: Provided is a zoom lens that has a four-lens configuration and is capable of having a viewing angle of larger than 180°. Provided is an infrared zoom lens that has a long back focus. The present invention comprises a first lens group that has a negative refractive power, and a second lens group that has a positive refractive power. During zooming, the first lens group and the second lens group move on an optical axis, and each of the first lens group and the second lens group is configured of two single lenses.

Abstract: An optical system incorporating a compact internal field of view switch configured to switch the field of view of the optical system between a narrow field of view and a wide field of view while maintaining a constant exit aperture size. In one example the optical system includes an active imaging sub-system optically coupled to the exit aperture, and the field of view switch is positioned between the exit aperture and the active imaging sub-system. In one example the field of view switch is configured as a pupil relay having non-unity magnification.

Abstract: A collector mirror exchanging apparatus capable of safely and easily exchanging a collector mirror for collecting extreme ultra violet light emitted from plasma generated within a chamber of an extreme ultra violet light source apparatus. The collector mirror exchanging apparatus includes: a supporting base for supporting a collector mirror or a collector mirror structure; and a guiding rail disposed on the supporting base and regulating a moving direction of the collector mirror or the collector mirror structure; wherein at least the collector mirror is taken out of the chamber by moving the collector mirror or the collector mirror structure along the guiding rail on the supporting base.

Abstract: A tunable, achromatizing optical system for use with a broadband imaging modality system for imaging objects having a range of longitudinal chromatic aberration (LCA) values. The optical system includes an achromatizing component and a parfocal component, for example, a zoom system. A method for tuning the wavefront curvature of different chromatic components of objects having a range of longitudinal chromatic aberration (LCA) values when imaged by a broadband imaging modality system includes the steps of providing a broadband imaging modality system having an entrance pupil, for imaging an object having longitudinal chromatic aberration; providing a tunable, achromatizing optical system; and varying the focal length of the parfocal component while maintaining a conjugate relationship between the achromatizing component and the entrance pupil of the broadband imaging modality system.

Abstract: A pair of spectacles that can automatically change its power so that a fixation region of interest (ROI) of the user is always in focus. The automatic accommodative spectacle device includes focusing elements, scene sensors, scene analyzer, focus engine, focusing element controller, and power supply. The scene analyzer determines the fixation ROI in the scene by analyzing the scene images. The fixation ROI is used to determine powers for the focusing elements in order to bring the fixation ROI into focus. The focusing element controller carries out the needed optical power adjustment to apply to the focusing elements. Optional light sources may be provided to the scene sensors. Additional optional eye sensor(s), eye light source and line of sight detector can be used to help the scene analyzer extract the fixation ROI.

Abstract: A collector mirror exchanging apparatus is capable of safely and easily exchanging a collector mirror for collecting extreme ultra violet light emitted from plasma generated within a chamber of an extreme ultra violet light source apparatus. The collector mirror exchanging apparatus includes: a supporting base for supporting a collector mirror or a collector mirror structure; and a guiding rail disposed on the supporting base and regulating a moving direction of the collector mirror or the collector mirror structure; wherein at least the collector mirror is taken out of the chamber by moving the collector mirror or the collector mirror structure along the guiding rail on the supporting base.

Abstract: This invention is directed to provide an infrared camera lens that is simple in lens configuration and has lens pieces including only spherical surfaces but no aspheric surfaces. The invention is also directed to provide an infrared camera lens of a design that facilitates and implements an airtight environment within the lens barrel because the foremost or first lens closest to the object stays still during focusing, and the entire length of the lens system is unchanged for focusing. The infrared camera lens comprises the foremost or first single spherical lens piece of positive refractivity, the succeeding or second single spherical lens piece of negative refractivity, and the third single spherical lens piece of positive refractivity. At least the second single spherical lens piece of negative refractivity or the third single spherical lens piece of positive refractivity is to be moved for focusing.

Abstract: The invention relates to a dual-field (NF and WF) imaging system comprising an optronic detector (1) and an optical combination of narrow-field focal length FNF having, an optical axis a front lens, a narrow-field entrance pupil situated in the vicinity of the front lens, a real wide-field entrance pupil, that is to say situated upstream of the front lens, an intermediate focal plane (IFP). The optical combination has, on the optical axis, the following refractive groups: a convergent front group G1 of focal length F, where F<FNF/2, this group G1 comprising the front lens, a divergent field-change group G2 that can move along the optical axis, this group being situated upstream of the IFP in NF configuration and downstream of the IFP in WF configuration, a relay group G3 imaging the IFP on the focal plane of the detector.

Abstract: A continuous zoom lens arrangement can image MWIR and LWIR spectral bands to a common image plane. Such an exemplary optical system comprises eight infrared imaging lenses that all transmit over the wavelengths 3.5-11.0 microns and form a collocated image plane for the MWIR and LWIR spectral bands. The lens has six stationary lenses, and two lenses that move in arm axial fashion. A cold stop inside the dewar can act as the aperture stop of the system and control the stray light from reaching the FPA. The pupil is reimaged from the cold stop to near the first lens of the system to minimize the size of the lens. The optic is designed to operate at an f/number of 3.0 and provides a focal length range from 38 mm to 130 mm for a 640×480 element focal plane array with 20 micron square pixels. This has an equivalent image plane diameter of 16 mm. Such an optical system can work with a cold shield height of about 29.46 mm. The range in focal length result in an overall zoom change of 3.42×.

Abstract: An image sensor assembly includes a fixed focal length optical lens; a mirror that reflects light from the scene to an optical lens and moves into a plurality of positions; and an image sensor that receives the light after it passes through the optical lens and captures a plurality of images that represents each image captured from each position of the mirror; wherein at least portions of the plurality of images are stitched together to form a composite image with a desired zoom factor.

Abstract: A mid infrared spectral band continuous zoom system is described herein that can provide a continuous zoom range with a focal length change greater than 25× when thermally imaging a distant object. In addition, a method is described herein for using the mid infrared spectral band continuous zoom system to thermally image the distant object.

Abstract: An ultra-broadband ultraviolet (UV) catadioptric imaging microscope system with wide-range zoom capability. The microscope system, which includes a catadioptric lens group and a zooming tube lens group, has high optical resolution in the deep UV wavelengths, continuously adjustable magnification, and a high numerical aperture. The system integrates microscope modules such as objectives, tube lenses and zoom optics to reduce the number of components, and to simplify the system manufacturing process. The preferred embodiment offers excellent image quality across a very broad deep ultraviolet spectral range, combined with an all-refractive zooming tube lens. The zooming tube lens is modified to compensate for higher-order chromatic aberrations that would normally limit performance.

Abstract: Disclosed is an ultrasonic lens configuration permitting the production of an acoustic field from low frequency ultrasound waves with predictable regions of energy concentration. The lens comprises at least three adjacent convex surface contours. Each surface contour corresponds to an arc of an ellipse. The first surface contour is within the center of the lens and is flanked by two adjacent contours. The flanking contours correspond to arcs from two symmetrical ellipses having semi-latus rectums at least equal to the semi-latus rectum of the ellipse to which the first, central, contour corresponds. The contours of the lens are arranged such that the flanking contours extend past the first contour by positioning the contours so that if the ellipses to which they correspond were drawn the ellipses of the flanking contours directly adjacent to the first contour would have their centers aligned on a plane parallel to and not below the major or minor axis of the ellipse of the first contour.

Abstract: The invention relates to a dual-field (NF and WF) imaging system comprising an optronic detector (1) and an optical combination of narrow-field focal length FNF having, an optical axis a front lens, a narrow-field entrance pupil situated in the vicinity of the front lens, a real wide-field entrance pupil, that is to say situated upstream of the front lens, an intermediate focal plane (IFP). The optical combination has, on the optical axis, the following refractive groups: a convergent front group G1 of focal length F, where F<FNF/2, this group G1 comprising the front lens, a divergent field-change group G2 that can move along the optical axis, this group being situated upstream of the IFP in NF configuration and downstream of the IFP in WF configuration, a relay group G3 imaging the IFP on the focal plane of the detector.

Abstract: Imaging optical systems having good transmission and that are well corrected over the full 315 nm-1100 nm ultraviolet-visible-infrared (UV-VIS-IR) wavelength band are disclosed. A wide variety of apochromatic and superachromatic design examples are presented. The imaging optical systems have a broad range of applications in fields where large-bandwidth imaging is called for, including but not limited to forensics, crime scene documentation, art conservation, forgery detection, medicine, scientific research, remote sensing, and fine art photography.

Abstract: Provided is an infrared imaging optical system with an advantageously varying focal length across the field of view. More specifically, in a particular embodiment, provided is an inverse telephoto lens group having a field of view on the order of at least two radians. The focal length of the lens group is structured and arranged to vary in a pre-determined fashion across the field of view. An IR detector is optically coupled to the inverse telephoto lens group. A pupil is disposed between the IR detector and the inverse telephoto lens group.

Abstract: An infrared lens system including a focus section that focus infrared radiation at an image plane, and a zoom section that adjusts a desired focal length of the infrared radiation, the focus section and zoom section including a plurality of lens elements which are located along an optical axis in optical communication with each other, the focus section and zoom section each including a fixed lens fixed with respect to the optical axis and a movable lens arranged for movement along the optical axis.

Abstract: An electronic imaging device includes a zoom lens that includes a plurality of lens groups and an imaging element that converts an optical image formed by the zoom lens into an electric signal. The zoom lens includes at least a first lens group having a negative focal length and a second lens group having a positive focal length sequentially from an object side, and a diaphragm on the object side of the second lens group. The diaphragm includes a first diaphragm having an aperture size A and a second diaphragm having an aperture size B, where A is greater than B, and the diaphragm is controlled such that the first diaphragm is effective on a long focus end and the second diaphragm is effective on a short focus end.

Abstract: A lighting assembly topology that utilizes spectrum controlling materials to render the illumination compatible with night vision imaging systems. The lighting assembly can be used as either a general illumination source or can be used as a backlight for a transmissive display such as a liquid crystal display. The lighting assembly makes use of spectral filtering which is both transmissive and absorptive for specific spectral regions. The exit port of the lighting assembly is completely filtered with a red and near infrared reflective filter. The absorption of the near infrared spectrum to which NVIS are sensitive is reflected by the typical near infrared reflective filter covering the exit port and absorbed within the material lining the housing of the lighting assembly.

Abstract: An apparatus, system, and method for a projection device having a camera to provide for adjustments based at least in part on a series of captured images are disclosed herein.

Abstract: An ultra-broadband ultraviolet (UV) catadioptric imaging microscope system with wide-range zoom capability. The microscope system, which comprises a catadioptric lens group and a zooming tube lens group, has high optical resolution in the deep UV wavelengths, continuously adjustable magnification, and a high numerical aperture. The system integrates microscope modules such as objectives, tube lenses and zoom optics to reduce the number of components, and to simplify the system manufacturing process. The preferred embodiment offers excellent image quality across a very broad deep ultraviolet spectral range, combined with an all-refractive zooming tube lens. The zooming tube lens is modified to compensate for higher-order chromatic aberrations that would normally limit performance.

Abstract: An ultra-broadband ultraviolet (UV) catadioptric imaging microscope system with wide-range zoom capability. The microscope system, which comprises a catadioptric lens group and a zooming tube lens group, has high optical resolution in the deep UV wavelengths, continuously adjustable magnification, and a high numerical aperture. The system integrates microscope modules such as objectives, tube lenses and zoom optics to reduce the number of components, and to simplify the system manufacturing process. The preferred embodiment offers excellent image quality across a very broad deep ultraviolet spectral range, combined with an all-refractive zooming tube lens. The zooming tube lens is modified to compensate for higher-order chromatic aberrations that would normally limit performance.

Abstract: A vehicle vision system displays a vehicle pathway image that includes a reticle for visually identifying the in-path portion of the image. A reticle array is disposed between a video camera chip and a lens, and includes a conical or frustro-conical region of substantially un-attenuated light transmissivity surrounded by a region of perceptibly attenuated light transmissivity, such that in-path portions of the displayed image are substantially unchanged and out-of-path portions of the displayed image are perceptibly attenuated. The reticle array may also include a number of reduced transmissivity lines traversing its conical or frustro-conical region to produce a series of receding stadia lines in the in-path portion of the displayed image, enabling the driver to reliably discern the range of displayed objects.

Abstract: An optical system includes a plurality of optical elements having finite refractive power and an electronic imaging device disposed at an image side of the optical system. At least one of the plurality of optical elements is made of resin, and an infrared-cut coating is applied to at least one face of the optical element that is made of resin.

Abstract: An optical system projecting onto an image plane an object that is disposed at infinity by an intermediate image. The optical system includes a front group and a relay optic, each including a plurality of lenses, the intermediate image disposed between the front group and the relay optic. The optical system being configured as the object lying at infinity with at least two switchable and/or zoomable fields of view, the fields of view being imaged into the image plane. The front group including at least three lenses successively disposed towards the image plane. A first one of the lenses including of Ge, at least a second of the lenses including of ZnSe, and at least a third of the lenses including of either MgF2, CaF2 or MgO.

Abstract: A spatial light modulator comprises: a first substrate (25); a second substrate (26); a layer of electrooptic material disposed between the first substrate and the second substrate. A first electrode arrangement (27) is disposed over the first substrate (25); and a second electrode arrangement (35) is disposed over the second substrate (26). The first electrode arrangement (27) comprises first and second electrode layers (28,29) disposed over the first substrate, with the spacing between the first electrode layer (28) and the first substrate (25) being different to the spacing between the second electrode (29) layer and the first substrate (25). The first electrode layer (28) and the second electrode arrangement (35) are configured so as to co-operate, in use, to define a plurality of first addressable regions in the electrooptic material.

Abstract: A night vision device provides both an amplified visible light image and an infrared image, overlayed upon each other so that they appear to be a single image. A user may select to utilize either an intensified visual image only, an infrared image only, or ratios of both images simultaneously. Dichroic surfaces within the night vision device are utilized first to separate light into visible and infrared portions, and then to recombine the visible and infrared images to a single image.

Abstract: An image-sensing apparatus has a zoom lens system for forming an optical image of an object with variable magnification, which zoom lens system includes a plurality of lens units and achieves zooming by varying distances between the lens units, and an image sensor for converting the optical image formed by the zoom lens system into an electrical signal. The zoom lens system has, from the object side, a first lens unit that has a positive optical power, includes a reflective member for turning the optical path, and is kept stationary relative to the image sensor during zooming, a second lens unit that is disposed on the image side of the first lens unit and has a negative optical power, an aperture stop that is disposed on the image side of the second lens unit and is kept stationary relative to the image sensor during zooming, and at least one lens unit that is disposed on the image side of the aperture stop and is moved relative to the image sensor during zooming.

Abstract: An optical system including a diffractive optical element, and an optical member for suppressing incidence of ultraviolet radiation on the diffractive optical element is disclosed. The optical member is disposed on a light incident side of the diffractive optical element. The optical member has optical power to achieve an optical system that has high optical performance and preferable environmental durability.

Abstract: Imaging lens device has a zoom lens system and an image sensor. The zoom lens system has a first reflecting surface, a first movable lens unit, an aperture stop, a second reflecting surface, a second movable lens unit. A first reflecting surface bends a first optical axis which is an incident optical axis of the zoom lens system 90 degrees into a second optical axis. A second reflecting surface bends the second optical axis 90 degrees into a third optical axis. The first optical axis, the second optical axis and the third optical axis are mutually perpendicular. The first movable lens unit and the aperture stop are disposed on the second optical axis. The second movable lens unit is disposed on the third optical axis. During zooming, the first and second reflecting surfaces and the aperture stop are stationary; the first and second movable lens units are moved, respectively.

Abstract: A zoom lens system is disclosed. The zoom lens system forms a final image of an object and a first intermediate real image between the object and the final image. The zoom lens system includes a first optical unit located between the object and the first intermediate real image. The first optical unit comprises at least one optical subunit which is moved to change the size (magnification) of the first intermediate real image. The zoom lens system also includes a second optical unit located between the first intermediate real image and the final image, at least a portion of which is moved to change the size (magnification) of the final image. The zoom lens system provides a wide zoom range of focal lengths with continuous zooming between the focal lengths and optional image stabilization.

Abstract: A zoom lens assembly (10) compensates optically, as opposed to mechanically, for changes in temperature. In a preferred embodiment a difference in focus between WFOV and NFOV zoom lens positions, over temperature, is minimized such that any actual shift in focus falls within the depth of focus of the zoom lens assembly. The zoom lens assembly has, along an optical axis, first and third lens elements (12,16) that are made from a first material and that have a positive power, a second lens element (14) interposed between the first and third lens elements and movable along the optical axis between a WFOV and NFOV position. The second lens element has a negative power and is made of a second material. The materials are selected such that a change in refractive index for a change in temperature of the first material is less than a change in refractive index for a change in temperature of the second material.

Abstract: A method and lens system for modifying the modulation transfer function of the light passing through the lens system to a camera or other imaging system that includes providing a spatial frequency response modifying (SFRM) filter within the lens system. The SFRM filter may be a thin film(s) or other type of modifying filter, including any conventional diffusion filters. The SFRM filter is located along the optical axis where the on-axis, zero field angle light rays are collimated in any lens system and form light beam(s) of a substantially constant cross sectional area throughout the range of focusing of a prime objective lens or throughout the ranges of zooming and focusing of an objective zoom lens for providing a consistent modulation transfer function of the light reaching the camera or other imaging system.