Abstract: A zoom lens includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a reflection member configured to bend an optical path, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power. In the zoom lens, two or more lens units of the first through the third lens unit move during zooming. In addition, in the zoom lens, the third lens unit includes a first lens sub-unit, and a second lens sub-unit configured to move in a direction having a component perpendicular to the optical axis to displace an image forming position.

Abstract: An optical apparatus (10) for an optoelectronic sensor (100, 200) which has at least one lens (14a-b), wherein a further optical element (18) is provided in the beam path of the optical apparatus (10) for extending the depth of field, wherein the optical element (18) is made and/or arranged such that a part of the beam path remains free and thus generates a first depth of field; and wherein the optical element (18) has a planoparallel zone which only covers a part of the beam path of the optical apparatus (10) and thus generates a second depth of field.

Abstract: A dual lens optical system including a first optical system and a second optical system includes at least one reflection member to selectively redirect object lights in first and second directions toward a photographing device. The first optical system includes, in order from an object to the photographing device along the optical axis, a first lens group comprising a first reflection member, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power. The second optical system shares at least one optical element with the first optical system.

Abstract: An optical assembly uses a plastic prism with one flat surface and a collimating lens optic to provide the capability of imaging a color micro-display to the eye. The collimating optic and flat prism surface can allow for aberration-free diopter adjustment and an image with very low-magnitude, nearly-symmetric distortion. The collimating optic can also provide environmental protection of the prism involving an optical plastic device. The input illumination from the micro-display enters the prism, is reflected two times within the prism, exits the prism, and passes through the collimating optic before being viewed by the eye. Such an optical assembly can provide a field of view with eye-relief and exit pupil when viewing a full-color micro-display.

Abstract: A dual lens optical system includes a first optical system redirecting an optical axis of light representing an image of an object by 90° to form an image on a image sensor, and a second optical system having a movable reflection member configured to be selectively positioned on the part of the redirected optical axis of the optical axis of light passing through the first optical system, and redirecting the light representing the image of the object by 90° using the movable reflection member to form an image on the image sensor, wherein the first optical system and the second optical system share lenses and the image sensor located after the movable reflection member along an optical path.

Abstract: A camera configured for a predetermined environment can be made low profile in the following manner. The camera includes an image sensor that has a light sensitive portion that can sense light from the predetermined environment. A substantially opaque mask is disposed above the light sensitive portion of the image sensor and has at least one opening through which the image sensor senses light. The low profile structure of the camera can be realized with substantially transparent material disposed between the substantially opaque mask and the image sensor that has index of refraction that is greater than an index of refraction of the predetermined environment. Accordingly, light through the opening refracts as it passes through the substantially transparent material to the image sensor.

Abstract: A high performance zoom lens system suitable for use with a camera is disclosed. The zoom lens systems employs liquid optics and a movable lens group to provide optical performance over the zoom focal length range at focus distances from close to infinity. The system also provides compensation for undesirable thermally induced effects by adjustments of the zoom group and the variably shaped optical surface in the liquid lens cell.

Abstract: The invention provides a viewing optical system comprising: a screen on which an object image by a taking lens is formed, an image erection optical system for erecting the object image formed on the screen, and an eyepiece lens system of positive refracting power for guiding a light beam leaving the image erection optical system to the eyeball of a viewer, wherein: the image erection optical system comprises a plurality of reflecting surfaces, the eyepiece optical system comprises, in order from a screen side to an exit pupil side, a first lens element of negative refracting power, a second lens element convex on both the screen side and the exit pupil side, and a third lens element that is of negative refracting power and has a meniscus shape concave on the exit pupil side, and the third lens element satisfies the following condition (1): 0.13<DL3/fe<0.

Abstract: A zoom lens system comprising a plurality of lens units each composed of at least one lens element, wherein an interval between at least any two lens units is changed so that an optical image is formed with a continuously variable magnification, the zoom lens system comprises a first lens unit having positive power, a second lens unit that includes a lens element having a reflecting surface and has negative power and subsequent lens units including at least one lens unit having positive power, and the condition: 0.50<(C?S)/H<1.00(C=?(2R·dR?dR2), S is a sag of the image side surface of the most object side lens element in the second lens unit at height H, H is one-half of an optical axial thickness of the lens element having a reflecting surface, R is a radius of curvature of the image side surface, and dR is an interval between the most object side lens element and the lens element having a reflecting surface) is satisfied.

Abstract: An exemplary super-wide-angle lens includes a lens barrel, a set of imaging lenses, and a prism. The set of imaging lenses is received in the lens barrel. The prism has three light incident surfaces, each of which is coated with a unique color filter for exclusively transmitting a predetermined color light, and a light emissive surface. The prism is positioned such that each of the light incident surfaces is configured for receiving light from a unique field of view of the super-wide-angle lens and the light emissive surface faces the set of imaging lenses, and is structured so that light transmitting in the prism is directed from the light incident surfaces to the light emissive surface.

Abstract: The refractive, transmissive or diffractive optical elements are made from a ceramic containing one or more oxides of the type X2O3, which is transmissive for visible light and/or for infrared radiation and which has a cubic crystal structure analogous to that of Y2O3. In preferred embodiments X is Y, Sc, In, or a lanthanide element, namely La to Lu, and in particular is Lu, Yb, Gd, or La. Also mixtures of oxides of the type X2O3 with oxides having different stoichiometries, such as HfO2 and/or ZrO2, may be present, as long as the cubic structure of the ceramic is maintained.

Abstract: An image pickup apparatus includes a first lens for converging light incident thereto through a first field area, a first prism to which light is incident through a second field area at a right of the first field area, a second lens for converging the light emitted from the first prism, a second prism to which light is incident through a third field area at a left of the first field area, and a third lens for converging the light emitted from the second prism. The respective lenses are placed at areas corresponding to the vertices of a triangle in a front view.

Abstract: A method of controlling the point spread function of an image projected with said image being diffused by a filter; said point spread function is a result of the application of spatial filter(s) on said image; with said control of the point spread function effected by varying the distance between such image and said spatial filter(s) and varying the bidirectional scattering transmission function of the spatial filter(s). Said spatial filter may be a holographic diffuser, which by method of manufacture has a well defined bi-directional scattering transmission spread function. Control of said spread function is particularly useful to maintain image quality while abating moiré interference in situations where two periodic patterns are layered causing moiré interference.

Abstract: An image pickup optical system includes a first-lens unit having negative refractive power; a second-lens unit having positive refractive power and being disposed closer to an image side than the first-lens unit; an aperture; and a diffraction optical part provided on the joint surface of a first-cemented lens closer to the image side than the aperture. The focal length of the whole system, the Abbe number of the negative lens of a second-cemented lens closer to the image side than the aperture, the focal length within the air, the Abbe number of a negative lens closer to an object side than the aperture, the average value between the curvature radius closest to the object side and the curvature radius closest to the image side of the first-cemented lens including the diffraction optical part, the curvature radius of the diffraction optical part, and so forth, are set appropriately.

Abstract: An apparatus and method is characterized by providing an optical transfer function between a predetermined illuminated surface pattern, such as a street light pattern, and a predetermined energy distribution pattern of a light source, such as that from an LED. A lens is formed having a shape defined by the optical transfer function. The optical transfer function is derived by generating an energy distribution pattern using the predetermined energy distribution pattern of the light source. Then the projection of the energy distribution pattern onto the illuminated surface is generated. The projection is then compared to the predetermined illuminated surface pattern to determine if it acceptably matches. The process continues reiteratively until an acceptable match is achieved.

Abstract: A total-internal-reflection (TIR) lens for color mixing includes a body member having an outer surface and an interior open channel extending longitudinally through the body member. The body member and the interior open channel are substantially symmetric with respect to an optical axis, and the outer surface is shaped to provide total internal reflection. The body member has a first end surface region at a first end of the open channel for accommodating a light source and a second end surface region opposite the first end region. The second end surface region includes a plurality of refractive surface regions positioned around the second end region of the open channel. The lens is configured to provide projected light substantially centered with respect to the optical axis when the light source is positioned off the optical axis. In a specific embodiment, a lighting apparatus for providing centered white light includes such a lens and a plurality of light sources.

Abstract: A dual lens optical system includes a first optical system redirecting an optical axis of light representing an image of an object by 90° to form an image on a image sensor, and a second optical system having a movable reflection member configured to be selectively positioned on the part of the redirected optical axis of the optical axis of light passing through the first optical system, and redirecting the light representing the image of the object by 90° using the movable reflection member to form an image on the image sensor, wherein the first optical system and the second optical system share lenses and the image sensor located after the movable reflection member along an optical path.

Abstract: A Risley integrated steering module is disclosed. The beam steering device consists of an outer assembly rotatable about an axis, and an inner assembly rotatable about the axis and positioned radially within the outer assembly. The beam steering device also includes a first prism connected to the outer assembly and a second prism connected to the inner assembly, and a stationary assembly, with the outer and inner assemblies being rotatable about the portion of the stationary assembly. In an alternative embodiment, the inner assembly rotates within the stationary assembly. The beam steering device also consists of beam expansion optics carried by either the inner assembly or the stationary assembly.

Abstract: A lens particularly suited to elongated grooved lens holders such as heat sinks for light emitting diodes. The lens may have a curved surface which projects light in rectangular beams and a radial flange for engaging grooves of a grooved lens holder. Curvature is that of a flattened or compressed sine wave, with less than one full wave being formed along the lens. In one aspect of the invention, the crest of the wave, which would ordinarily be domed, may be flat. The radial flange has straight sides to enable contiguity when arrayed in abutment as well as for cooperating with the grooves of the lens holder.

Abstract: This invention has as its object to provide a lens apparatus for an image pickup apparatus which can be reduced in size and is excellent in driving accuracy. In order to achieve the above-described object, this invention adopts a lens apparatus including a prism having an entrance surface which receives a light beam incident from a subject side, a reflection surface which deflects a light beam incident from the entrance surface, and an exit surface which emits a light beam deflected by the reflection surface toward an image pickup surface side, a prism holder which holds the prism, a lens group of subject side, and a lens group of image pickup surface side, wherein the lens group of subject side is fixed to the entrance surface of the prism and/or the lens group of image pickup surface side is fixed to the exit surface of the prism.

Abstract: A zoom lens system comprising a plurality of lens units each composed of at least one lens element, wherein an interval between at least any two lens units is changed so that an optical image is formed with a continuously variable magnification, the zoom lens system comprises a first lens unit having positive power, a second lens unit that includes a lens element having a reflecting surface and has negative power and subsequent lens units including at least one lens unit having positive power, and the condition: 0.50<(C?S)/H<1.00(C=?{square root over ( )}(2R·dR?dR2), S is a sag of the image side surface of the most object side lens element in the second lens unit at height H, H is one-half of an optical axial thickness of the lens element having a reflecting surface, R is a radius of curvature of the image side surface, and dR is an interval between the most object side lens element and the lens element having a reflecting surface) is satisfied.

Abstract: An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a positive refractive power; a second lens having one of a positive refractive power and a negative refractive power; and a third lens that corrects for aberration. At least one of the first and second lenses has a diffractive optical surface, the diffractive optical surface having twenty or less orbicular gratings in a range to pass an effective light ray.

Abstract: A lens for use with a light emitting source is provided. The lens has a main body with a light-collecting face and a light-emitting face and which defines an optical axis extending through the centers of these two faces. A pocket for receiving light from the light source is defined in the light-collecting face by an inner axially-facing surface surrounded by an inner radially-facing surface. The inner axially-facing surface is concave and has a spherical shape. The inner radially-facing surface has a non-spherical, tapered shape and extends between the axially-facing surface and an open end of the pocket. A light assembly incorporating the lens includes a light-emitting diode.

Abstract: A lens device used for an LED package includes a base portion, and a refracting portion formed on the top face of the base portion. A recess corresponding to the refracting portion is formed on the bottom face of the base portion. At least one notch connecting with the recess is also formed on the bottom face of the base portion. A surface of refracting portion is provided as a non-spherical convex surface. An indent is formed on the center of the non-spherical convex surface. The light emitted from the LED package is directed toward lateral side, and the angular intensity distribution has an asymmetrical batwing shape, so as to obtain an illuminating apparatus with uniformly illumination.

Abstract: A compact image taking lens system with a lens-surfaced prism of the present invention comprises a prism, an aperture stop, a first lens element, a second lens element, reflecting mirror surface, and image surface, optionally an infrared cut-off filter. By introducing a lens-surfaced prism, the compact image taking lens system with a lens-surfaced prism of the present invention has many advantages over the prior arts in the field of invention, such as compactness in thickness, small number of optical elements, high performance of optical quality, enough space for optional elements such as an infrared cut-off filter and diversity in optical geometries.

Abstract: A compact auto-focus image taking lens system with a Micromirror Array Lens and a lens-surfaced prism of the present invention comprises a lens-surfaced prism, an aperture stop, a first lens element, a second lens element, a Micromirror Array Lens, and an image surface, optionally an infrared cut-off filter. By introducing a Micromirror Array Lens and a lens-surfaced prism, the compact auto-focus image taking lens system with a Micromirror Array Lens and a lens-surfaced prism of the present invention has many advantages over the prior arts in the field of invention, such as compactness in thickness, small number of optical elements, high performance of optical quality, fast focusing speed, low power consumption, enough space for optional elements such as an infrared cut-off filter and diversity in optical geometries.

Abstract: The present invention provides: a lens optical system having a lens and a plastic block having two parallel planes, the plastic block being provided between the lens and a focal position of the lens to suppress a variation of a focal length due to a temperature change, and a photoelectric encoder including the lens optical system.

Abstract: It is to provide an optical element, an optical module holder including the optical element, an optical module, and an optical connector that can attenuate with high accuracy an amount of light coupled between an optical transmission line and a photonic element using light refraction, thereby realizing appropriate optical communication while reducing manufacturing costs. A light attenuating refractive surface 7 is formed on an optical surface 4 disposed on an optical path between an optical transmission line 2 and a photonic element 3 in a main body of the optical element. The light attenuating refractive surface 7 attenuates the amount of light coupled between the optical transmission line 2 and the photonic element 3 by refracting and deflecting incident light.

Abstract: An image pickup apparatus includes a first lens for converging light incident thereto through a first field area, a first prism to which light is incident through a second field area at a right of the first field area, a second lens for converging the light emitted from the first prism, a second prism to which light is incident through a third field area at a left of the first field area, and a third lens for converging the light emitted from the second prism. The respective lenses are placed at areas corresponding to the vertices of a triangle in a front view.

Abstract: A zoom lens includes a focus unit, a zoom unit, an aperture stop, and an imaging unit having a splitting element that are arranged in that order from an object side to an image side. The splitting element includes an incident surface for a light beam, a half mirror surface for splitting the light beam into reflected light and transmitted light, a splitting exit surface from which the reflected light is emitted, and an exit surface from which the transmitted light is emitted. The incident surface and the exit surface are perpendicular to an optical axis of the zoom lens. The ratio of the distance from the aperture stop to the exit surface and the equivalent air length from the aperture stop to an image plane of the zoom lens and the ratio of the effective diameters of the exit surface and the splitting exit surface are set properly.

Abstract: An optical system includes a front lens group, a stop, and a rear lens group arranged successively in order from the object side toward the image side. The front lens group includes a solid material element having a refractive action. The rear lens group includes a diffractive optical element. The solid material element is formed on at least one transmissive surface of a refractive optical element. An Abbe number of a solid material of the solid material element with respect to the d line, a partial dispersion ratio of the solid material with respect to the g line and the F line, respective thicknesses of the solid material element and the refractive optical element when measured on the optical axis, and respective focal lengths of the diffractive optical portion of the diffractive optical element and the solid material element in air satisfy predetermined conditional expressions.

Abstract: A lens module includes a barrel, a lens, and a light leveling assembly. The barrel includes an opening, which allows a light to pass therethrough. The lens is accommodated in the barrel. The light leveling assembly is accommodated in the barrel. The light leveling assembly includes a substrate and a film. The substrate has a first surface where the film is disposed and an opposite second surface facing the lens. A thickness of the film is approximately equal to a quarter wavelength of the light. A refractive index of the film exceeds that of the substrate.

Abstract: Disclosed are image expanding lenses, display devices, and electronic devices incorporating the disclosed image expanding lenses. In accordance with a disclosed image expanding lens, the image viewed by the user is larger than the active area of the LCD panel underneath the lens, so that the border around, for example, the LCD display is hidden from viewing. The image expanding lenses may include a non-uniform transparent substrate, having for example, a wedge shape that may be the top surface of the display. The substrate in combination with prismatic films may bend the light output from an array of pixels so that the image hides the border of the display device. In this way, an electronic device can render an edgeless image to a viewer since the image of the electronic device is projected beyond an edge of the display device of the host electronic device.

Abstract: System and method for utilizing two prisms spatially separated is provided. The two prisms spatially separated allows the two prisms typically found in a TIR optical relay system to be spatially separated. In an embodiment, one or more optical relay lenses are interposed between the two prisms. The prism positioned on the object side may be integrated into one or more of the optical relay lenses, thereby further simplifying the optical relay design. In another embodiment, the one or more optical relay lenses may have an optical axis that is offset from the optical axis of incoming light to cause a pupil shift. An aspherical lens may be included to correct for the pupil shift and create a more uniform illumination image.

Abstract: A photographing optical system includes at least one of a positive lens and diffractive optical element being provided closer to an object side of the system than an intersection P of a light axis and paraxial chief ray, and a negative lens, provided closer to an image side than the intersection. The positive lens and the negative lens are formed of materials satisfying the following conditions when the maximum height of a paraxial marginal ray, passing through a lens surface, from the light axis at a location closer to the object side than the intersection is greater than a maximum height of the paraxial marginal ray, passing through a lens surface, from the light axis at a location closer to the image than the intersection: ?0.0015 ×?d +0.6425 <?gF 60 <?d where ?d is an Abbe number and ?gF is a partial dispersion ratio.

Abstract: A lens unit (20) includes a lens body (24) and a thin film (22) provided thereon. The thin film comprises a plurality of sections (220, 222, 224) from a center to a periphery. Each section has a different refractive index. The refractive index of the each section of the thin film increases from the center to the periphery of the lens body/thin film. Such a lens unit can be advantageously incorporated into a compact digital camera.

Abstract: The present invention provides a projection optical system which projects an image on a first object plane onto a second object plane, comprising at least four optical members which are arrayed in turn from the second object plane, and made of an isotropic crystal, wherein the at least four optical members are formed by alternately arraying optical members in each of which a <1 1 1> crystal axis is oriented along a direction of an optical axis, and optical members in each of which a <1 0 0> crystal axis is oriented along the direction of the optical axis.

Abstract: An illumination optical apparatus that substantially maintains a desirable profile even when changing the outer shape of light intensity distribution formed on an illumination pupil plane with an axicon system. The illumination optical system illuminates an irradiated surface based on light from an optical source and includes a prism system, which changes the interval along an optical axis between a pair of prisms to change the light intensity distribution on an illumination pupil plane.

Abstract: An optical apparatus including an optical system for bending an optical path in a first direction into a second direction substantially perpendicular to the first direction; and a prism for bending the optical path in the second direction with a plurality of reflecting surfaces so that the optical path spirals and leads into a third direction substantially perpendicular to the second direction.

Abstract: An image pickup apparatus includes an image pickup element and an optical system configured to form an image on the image pickup element. The optical system includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power and including a reflecting member configured to deflect an optical axis, and a rear lens unit having a positive refractive power and including at least one lens unit having a positive refractive power. The second lens unit is stationary for zooming. During zooming, the image pickup element moves, and an interval between the first lens unit and the second lens unit and an interval between the second lens unit and the rear lens unit vary.

Abstract: An imaging unit including an image sensor, an incident-side prism, an exit-side prism, and an intermediate optical system positioned therebetween, wherein light incident on the incident-side prism passes through the incident-side prism, the intermediate optical system and the exit-side prism to be incident on the image sensor, the imaging unit includes a housing supporting the incident-side prism, the exit-side prism and the intermediate optical system such that incident and exit optical axes of the incident-side prism, an optical axis of the intermediate optical system, and incident and exit optical axes of the exit-side prism all lie on a common plane; and a cover board, on which the image sensor is mounted, fixed to the housing so that the image sensor faces an exit surface of the exit-side prism, the cover board closing an opening of the housing.

Abstract: The present invention relates to a 3-dimensional image detector adapted to simultaneously detect images of an object viewed from multi-directions, including: a lens barrel; a refraction section mounted at a front end side of the lens barrel; a lens section mounted at the rear of the refraction section; and an image-detecting section mounted at the rear of the lens section for acquiring an image passed through the refraction section and the lens section.

Abstract: A mono-bloc catadioptric imaging lens comprising a solid body and a single-focal Maksutov type construction characterized by two refractive surfaces and two reflective surfaces wherein all surfaces are surfaces of revolution and wherein at least one surface is aspheric.

Abstract: Provided are wafer scale lenses having a diffraction surface as well as a refractive surface, and an optical system having the same. The wafer scale lens includes a lens substrate, a first lens element formed on the object side of the lens substrate, having a positive refractive power, a second lens element formed on the image side of the lens substrate, having a diffraction surface, and a third lens element deposited on the diffraction surface of the second lens element, having a negative refractive power. The invention allows miniaturized optical system and efficient calibration of angle of view, reducing the angle of light incident onto the diffractive surface, thereby increasing diffraction efficiency and eliminating high order diffraction light to improve picture quality.

Abstract: In this invention, to provide a compact zoom lens having a small number of optical element groups to be driven and a simple moving mechanism, at least one of a plurality of optical element groups arranged in the lens system includes a refractive power variable element of a transmission type which has a compensation function to correct focus movement caused by zooming and a focus function to correct focus movement caused by a variation in inter-object distance. The refractive power variable element is a liquid optical element including a first liquid having a conductivity or a polarity and a second liquid which is not mixed with the first liquid, the first liquid and the second liquid being enclosed in a container fluid-tight so as to define an interface therebetween having a predetermined shape, the liquid optical element being arranged such that a refractive power thereof is adjusted by changing a curvature of the interface.

Abstract: A zoom lens system comprising a plurality of lens units each composed of at least one lens element, wherein an interval between at least any two lens units is changed so that an optical image is formed with a continuously variable magnification, the zoom lens system comprises a first lens unit having positive power, a second lens unit that includes a lens element having a reflecting surface and has negative power and subsequent lens units including at least one lens unit having positive power, and the condition: 0.50<(C?S)/H<1.00(C=?{square root over ( )}(2R·dR?dR2), S is a sag of the image side surface of the most object side lens element in the second lens unit at height H, H is one-half of an optical axial thickness of the lens element having a reflecting surface, R is a radius of curvature of the image side surface, and dR is an interval between the most object side lens element and the lens element having a reflecting surface) is satisfied.

Abstract: This invention is directed to a device of “wide-angle diving lens”, primarily comprises a lens; and characterized by: the lens is made by a main lens and extended with a plurality of different angles of sub-window lens, or at the inner edge of the lens arranged Fresnel lens, or at the outer edge of the lens chamfered with embedded joint. Accordingly, the present invention “wide-angle diving lens” not only takes advantage of the multi-angles of lens to increase visible range and enhance the structure solidity but also applies Fresnel lens to modify the light refraction angle to enlarge visible range; and further assembly conveniently as well as no visible range disrupt.

Abstract: A single lens element used for converting a divergent pencil of rays, radiated from a light source, into a predetermined convergent state, wherein the single lens element is made from a resin and has a positive optical power due to a refraction effect and a positive optical power due to a diffraction effect, the diffraction effect is based on a diffraction structure formed on at least one of an incident side surface and an exit side surface of the single lens element, and the following expressions are satisfied: 0.1<NA<0.3 0.4<T/f<0.75 2.2<fr/f<3 here, f is a focal length of the entire single lens element, fr is a focal length due to the refraction effect of the single lens element, T is a thickness of the single lens element on an optical axis, and NA is a numerical aperture of a single lens element at an incident side.

Abstract: An image pick-up lens system includes an aperture stop (10), a biconvex first lens (20), a second lens (30) having a concave surface on an object side, and a third lens (40) having a concave surface on an image side. The aperture stop (10), the first lens (20), the second lens (30) and the third lens (40) are aligned in that order from the object side to the image side. All lenses in the system are made from a plastic or resin material, and one of them has a diffraction grating formed on a surface. The system satisfies conditions (1)-(5) as disclosed, in order to provide compactness, cost-effectiveness and improved optical performance.

Abstract: A zoom lens is disclosed having a zoom ratio larger than four with a field of view at the short focal length position larger than 85 degrees and with a minimal number of moving groups. The zoom lens utilizes a compound zoom structure comprising an NP or NPP zoom kernel followed by a P or PP zoom relay, with only two or three moving groups that can be used for both zooming, focusing and athermalization. An overall compact package size is achieved by the use of prisms to fold the optical path in strategic locations. An optional variable power liquid cell can provide close focusing with little or no focus breathing.