Abstract: The present disclosure discloses an optical imaging lens assembly. The optical imaging lens assembly includes, sequentially from an object side to an image side along an optical axis, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the seven lens having refractive power. The first lens has positive refractive power, an object-side surface thereof is a convex surface, and an image-side surface thereof is a convex surface; the second lens has negative refractive power, an object-side surface thereof is a convex surface; and an object-side surface of the fourth lens is a concave surface. A distance TTL along the optical axis from the object-side surface of the first lens to an imaging plane of the optical imaging lens assembly and a total effective focal length f of the optical imaging lens assembly satisfy TTL/f<1.

Abstract: Provided is a camera optical lens including, from an object side to an image side: a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, a fifth lens having a negative refractive power, a sixth lens having a positive refractive power, and a seventh lens having a negative refractive power, and the camera optical lens satisfies following conditions: 2.80?v1/v2?4.30; 5.00?f4/f?12.00; ?4.00?f5/f??1.50; and ?20.00?R13/R14??5.00. The camera optical lens has good optical performance while satisfying the requirements of ultra-thin, wide-angle lenses having large apertures.

Abstract: An optical lens in order from an object side to an image-forming side includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. An object-side surface of the first lens has a curvature radius R1, an image-side surface of the first lens has a curvature radius R2, an object-side surface of the third lens has a curvature radius R5, an image-side surface of the third lens has a curvature radius R6, an image-side surface of the seventh lens has an inflection point, a distance between the inflection point and an optical axis is h14, and the seventh lens has a radius H14. The optical lens satisfies at least one of the following conditions: 0.01?|R2/R1|; |R2/R1|?0.6; 0?|R5/R6|; |R5/R6|?2; 0.3?|h14/H14|; and |h14/H14|?0.9.

Abstract: A lens device consists essentially of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens is with negative refractive power and includes a convex surface facing an object side and a concave surface facing an image side. The second lens is a biconcave lens with negative refractive power. The third lens is with positive refractive power. The fourth lens includes a concave surface facing the object side. The fifth lens is with refractive power and includes a convex surface facing the object side. The sixth lens is with refractive power. The seventh lens is with positive refractive power. The first, second, third, fourth, fifth, sixth, and seventh lenses are arranged in order from the object side to the image side along an optical axis. The third lens and the fourth lens are cemented.

Abstract: An optical imaging lens including a first to a seventh lens elements arranged in sequence from an object side to an image side along an optical axis is provided. Each lens element includes an object-side surface and an image-side surface. An optical axis region of the image-side surface of the first lens element is concave. A periphery region of the object-side surface of the third lens element is concave. A periphery region of the image-side surface of the third lens element is convex. The fourth lens element has positive refracting power and an optical axis region of the image-side surface of the fourth lens element is concave. The fifth lens element has negative refracting power and an optical axis region of the image-side surface of the fifth lens element is concave. The sixth lens element has positive refracting power. Furthermore, other optical imaging lenses are also provided.

Abstract: A photographing optical lens assembly includes seven lens elements, the seven lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element. The first lens element has negative refractive power. The second lens element has negative refractive power. The third lens element has an object-side surface being concave in a paraxial region thereof. The fourth lens element has an image-side surface being convex in a paraxial region thereof.

Abstract: A wide-angle lens assembly comprises sequentially from an object side to an image side along an optical axis a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is a meniscus lens with negative refractive power. The second lens is a meniscus lens with positive refractive power. The third lens is a biconvex lens with positive refractive power. The fourth lens is with refractive power and includes a convex surface facing an object side. The fifth lens is with refractive power and includes a concave surface facing an image side. The sixth lens is with negative refractive power and includes a concave surface facing the object side.

Abstract: An optical photographing system includes a plurality of lens elements which include, in order from an object side to an image side: a first lens element, a second lens element and a last lens element. There is no additional lens element disposed between the first lens element and the second lens element, and there is no additional lens element disposed between the last lens element and an image surface. The first lens element has a first refractive surface, a first reflective surface, a second reflective surface and a second refractive surface. The first reflective surface faces toward the object side, and the second reflective surface faces toward the image side. At least one lens element of the optical photographing system has at least one lens surface with at least one inflection point.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of plastic material, the second lens is made of glass material, the third lens is made of glass material, the fourth lens is made of plastic material, the fifth lens is made of plastic material, and the sixth lens is made of plastic material. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of glass material, the second lens is made of plastic material, the third lens is made of plastic material, the fourth lens is made of glass material, the fifth lens is made of plastic material, and the sixth lens is made of plastic material. The camera optical lens further satisfies specific conditions.

Abstract: There is provided an imaging lens with high resolution which satisfies in well balance wide field of view, low-profileness and low F-number and properly corrects aberrations. An imaging lens comprises a first lens having negative refractive power, a second lens having the negative refractive power, a third lens, a fourth lens having the negative refractive power and a convex surface facing the image side near an optical axis, a fifth lens having at least one aspheric surface, and a sixth lens being double-sided aspheric lens and having a concave surface facing the image side near the optical axis, wherein the image-side surface of the sixth lens is an aspheric surface changing to the convex surface at a peripheral area.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens having positive refractive power; and a sixth lens, arranged in this order from an object side to an image plane side with spaces in between each of the lenses. The first lens is formed in a meniscus shape to have an object side convex surface. The second lens is formed in a meniscus shape. The third lens has at least one aspheric surface. The fourth lens has at least one aspheric surface and an object side concave surface. The fifth lens has two aspheric surfaces. The sixth lens has two aspheric surfaces and the image plane side convex surface. The fourth lens is arranged to be away from the fifth lens by a specific distance. The fourth lens has a specific Abbe's number.

Abstract: An imaging lens includes a first lens having at least one aspheric surface and positive refractive power; a second lens having at least one aspheric surface; a third lens having at least one aspheric surface; a fourth lens having at least one aspheric surface; a fifth lens having at least one aspheric surface; a sixth lens having two aspheric surfaces; and a seventh lens having two aspheric surfaces and negative refractive power, arranged in this order from an object side to an image plane side respectively with a space in between. The imaging lens has a total of seven lenses. The fourth lens and the sixth lens have specific Abbe's numbers.

Abstract: An imaging lens includes a first lens having at least one aspheric surface; a second lens having at least one aspheric surface; a third lens having at least one aspheric surface; a fourth lens having at least one aspheric surface; a fifth lens having at least one aspheric surface; a sixth lens having two aspheric surfaces; and a seventh lens having two aspheric surfaces, arranged in this order from an object side to an image plane side respectively with a space in between. The imaging lens has a total of seven lenses. The first lens is formed in a shape so that a surface on the object side is convex near an optical axis. The seventh lens is formed in a shape so that a surface on the image plane side is concave near the optical axis. The fifth lens and the sixth lens have specific Abbe's numbers.

Abstract: An imaging lens includes a first lens having at least one aspheric surface and positive refractive power; a second lens having at least one aspheric surface; a third lens having at least one aspheric surface; a fourth lens having at least one aspheric surface; a fifth lens having at least one aspheric surface; a sixth lens having two aspheric surfaces; and a seventh lens having two aspheric surfaces and negative refractive power, arranged in this order from an object side to an image plane side respectively with a space in between. The imaging lens has a total of seven lenses. The fifth lens is disposed away from the sixth lens by a specific distance on an optical axis. The second lens has a specific Abbe's number.

Abstract: A wide angle lens includes a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens and a seventh lens which are disposed in order from an object side. The first, second, third and sixth lenses are negative meniscus lenses, and the fourth, fifth and seventh lenses are positive lenses. The fifth lens is a glass lens, and the second, third, fourth, sixth and seventh lenses are plastic lenses. The sixth lens and the seventh lens constitute a cemented lens. When a center curvature radius on an image side face of the fifth lens is R52 and a focal length of an entire wide angle lens is f0, the center curvature radius R52 and the focal length f0 satisfy the following conditional expression: 2×f0?|R52|?5×f0.

Abstract: An optical image capturing system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element. The first, the second and the third lens elements all have refractive power. The fourth lens element with refractive power has both surfaces being aspheric. The fifth lens element with refractive power has both surfaces being aspheric. The sixth lens element with refractive power has an image-side surface having at least one convex shape at a peripheral region thereof and both surfaces being aspheric. The seventh lens element with refractive power has an image-side surface having at least one convex shape at a peripheral region thereof, wherein both surfaces being aspheric, and at least one surface has at least one inflection point thereon.

Abstract: An image picking-up system includes seven lens elements, which are, in order from an object side to an image side, a first lens group including a first lens element and a second lens element, a second lens group including a third lens element and a fourth lens element, and a third lens group including a fifth lens element, a sixth lens element and a seventh lens element. The third lens element has positive refractive power. The fourth lens element has an image-side surface being concave in a paraxial region thereof. At least one surface of object-side surfaces and image-side surfaces of the seven lens elements includes at least one inflection point.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The first lens is made of plastic material, the second lens is made of plastic material, the third lens is made of glass material, the fourth lens is made of plastic material, the fifth lens is made of plastic material, the sixth lens is made of plastic material, and the seventh lens is made of plastic material. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens includes, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The camera optical lens further satisfies specific conditions.

Abstract: A wide-angle lens includes a first lens group, a second lens group, and an aperture arranged in that sequence from object side to image side. The first lens group as a whole has a positive refractive power, and includes a first lens, a second lens, a third lens, and a fourth lens. The first lens has a negative refractive power. The second lens has a negative refractive power. The third lens has a negative refractive power. The fourth lens has a positive refractive power. The second lens group as a whole has a positive refractive power, and includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The fifth lens has a positive refractive power. The sixth lens has a negative refractive power. The seventh lens has a positive refractive power. The eighth lens has a positive refractive power.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The camera optical lens further satisfies specific conditions.

Abstract: An optical image capturing system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element. The first, the second and the third lens elements all have refractive power. The fourth lens element with refractive power has both surfaces being aspheric. The fifth lens element with refractive power has both surfaces being aspheric. The sixth lens element with refractive power has an image-side surface having at least one convex shape at a peripheral region thereof and both surfaces being aspheric. The seventh lens element with refractive power has an image-side surface having at least one convex shape at a peripheral region thereof, wherein both surfaces being aspheric, and at least one surface has at least one inflection point thereon.

Abstract: An imaging lens includes a first lens having at least one aspheric surface; a second lens having at least one aspheric surface; a third lens having at least one aspheric surface; a fourth lens having at least one aspheric surface; a fifth lens having at least one aspheric surface; a sixth lens having two aspheric surfaces; and a seventh lens having two aspheric surfaces, arranged in this order from an object side to an image plane side. The first lens is formed in a shape so that a surface thereof on the object side is convex near an optical axis thereof. The seventh lens is formed in a shape so that a surface thereof on the image plane side is concave near the optical axis thereof. The first lens and the sixth lens have specific Abbe's numbers.

Abstract: There is provided an optical system including: a first lens having positive refractive power; a second lens having positive refractive power; a third lens having refractive power and having a convex object-side surface; a fourth lens having refractive power; and a fifth lens having refractive power, wherein the first to fifth lenses are sequentially disposed from an object side, whereby spherical aberration and coma aberration may be improved to realize high resolution in images captured thereby and increase an amount of light incident through the lenses to an image sensor.

Abstract: There is provided super wide angle lens module, including: a first lens having negative refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; and a fifth lens having positive refractive power and having a meniscus shape convex toward an image side, wherein the third lens satisfies Equation 1, Nd3>1.7??Equation 1 where Nd3 represents a refractive index of the third lens.

Abstract: An imaging lens is constituted essentially by six lenses, including: a first lens having a positive refractive power and is of a meniscus shape with a convex surface toward the object side; a second lens having a negative refractive power; a third lens; a fourth lens having a positive refractive power; a fifth lens having a negative refractive power and a concave surface toward the image side; and a sixth lens of a biconcave shape, provided in this order from the object side. The imaging lens satisfies a predetermined conditional formula.

Abstract: A wide angle lens includes in order from an object side, a front lens unit having a positive refractive power, one focusing lens having a negative refractive power, and a rear lens unit having a positive refractive power, and at the time of focusing, the focusing lens moves on an optical axis, and the following conditional expressions (1) and (2) are satisfied. 0.1<f1/SSD<0.5??(1) 3.

Abstract: A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens is with negative refractive power. The second, third, fourth and sixth lens are with refractive power. The fifth lens is with positive refractive power. The lens assembly satisfies: 0.078?BFL/TTL?0.4, 0.01?f/TTL?0.61, (Nd1+Nd2+Nd3+Nd4+Nd5+Nd6)/6<(Nd2+Nd3)/2 wherein BFL is a distance from an image side surface of the sixth lens to an image plane along the optical axis, TTL is a distance from the convex surface of the first lens to the image plane along the optical axis, f is an effective focal length of the lens assembly, and Nd1, Nd2, Nd3, Nd4, Nd5 and Nd6 are indexes of refraction of the first, second, third, fourth, fifth and sixth lenses.

Abstract: An imaging lens consists of, in order from the object, a negative first lens, a positive second lens, a positive third lens, a negative fourth lens, a positive fifth lens, a positive sixth lens, and a negative seventh lens. When ?d7 is the Abbe's number of the material for the seventh lens, f is the focal length of the entire system, and f5 is the focal length of the fifth lens, the following conditional formulae are satisfied: ?d7<55??(2) 1.25<f5/f??(10).

Abstract: An imaging lens substantially consists of a front-group consisting of a first lens having a negative meniscus shape with its convex surface facing an object side, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having a negative meniscus shape with its concave surface facing an image side and a fifth lens having positive refractive power, and the front-group having positive refractive power as a whole, a stop, and a rear-group consisting of a sixth lens having positive refractive power and a seventh lens having a negative meniscus shape with its concave surface facing the object side, and the rear-group having positive refractive power as a whole, in this order from the object side. A predetermined conditional formula about a combined focal length of the first lens and the second lens, and a focal length of an entire system is satisfied.

Abstract: A fixed-focus projection lens has a first lens group and a second lens group in sequence along an optical axis from a screen side to a light modulator side. The first lens group has a positive refractive power, and the second lens group has a positive refractive power. The first lens group has two lenses, and the refractive powers of the lenses are negative and positive. The second lens group has five lenses, and the refractive powers of the lenses respectively are negative, negative, positive, positive, and positive. The fixed-focus projection lens has the features of small size and high optical performance.

Abstract: An optical image capturing lenses includes, in order from an object side to an image side, a front lens group, a stop, and a rear lens group. The front lens group includes, in order from the object side to the image side, at least a first lens element and a second lens element. The first lens element has a convex object-side surface and a concave image-side surface. The rear lens group includes, in order from the object side to the image side, at least a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element. The sixth lens element is made of plastic material. The object-side surface and the image-side surface of the sixth lens are aspheric. The sixth lens element has at least one inflection point formed on at least one of the object-side surface and the image-side surface thereof.

Abstract: An optical system WL has, in order from an object, a first lens group G1 having negative refractive power and a second lens group G2 having positive refractive power, wherein the first lens group G1 is fixed and the second lens group G2 moves upon focusing from an object at infinity to an object at a finite distance, and the second lens group G2 is formed of a front group G2a located closer to the object than an aperture stop S disposed in the second lens group G2, and a rear group G2b located closer to an image than the aperture stop S.

Abstract: Wide-angle projection lens, as well as optical engines and projection display devices comprising such projections lens are described. In one embodiment, a wide-angle projection lens is described comprising in sequential order from a screen side a first lens group of negative refractive power, a second lens group of positive refractive power, a third lens group of positive refractive power; and a fourth lens group of positive refractive power. At least one lens group has an aspheric surface. The ratio of the focal length of the wide-angle projection lens (F) to the focal length of each of the lens groups (F1, F2, F3, and F4) is such that |F1/F|>1.3, F2/F>2, 1<F3/F<2 and 1.5<F4/F<8.

Abstract: The present invention provides a projection prime lens including first lens group, a second lens group, and a third lens group arranged in sequence along an optical axis from a screen side to a light modulator side. The first lens group has negative refractive power and includes a first lens with negative refractive power and a second lens with negative refractive power. The second lens group has positive refractive power and includes a third lens with positive refractive power and a fourth lens with positive refractive power The third lens group has positive refractive power and includes a fifth lens with negative refractive power, a sixth lens with positive refractive power, and a seventh lens with positive refractive power. Therefore, the projection prime lens of the present invention has a small size and a good image quality.

Abstract: A retrofocus wide-angle lens system is provided, wherein the entire the wide-angle lens system is divided at a position that satisfies the following condition (1) between a theoretical front lens group having a negative refractive power, and a theoretical rear lens group having a positive refractive power including the diaphragm, at a minimum focal length, and wherein a flat parallel plate is disposed at the position that satisfies the following condition (1): 1.2<|fF/f|<4.0 . . . (1), wherein fF designates the focal length of the theoretical front lens group having a negative refractive power, and f designates the focal length of the entire the wide-angle lens system.

Abstract: An optical lens system with a wide field of view comprises, in order from the object side to the image side: a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a second lens element; a third lens element; a fourth lens element having a concave object-side surface and a convex image-side surface; a fifth lens element with positive refractive power; a sixth lens element with negative refractive power; a seventh lens element, one of an object-side surface and an image-side surface being aspheric. There are seven lens elements with refractive power. By adjusting the arrangement of curvature, refractive power of the respective lens elements and a stop, sufficient field of view can be obtained and the aberrations of the system can be corrected in order to obtain good image quality.

Abstract: Provided is an imaging optical system and an image acquisition apparatus that can be suitably used in a small-diameter endoscope while having an ultra-wide angle of view. Provided is an image optical system (1) containing, in order from the object side, a negative front group (FG), an aperture stop (S), and a positive back group (BG), wherein the front group (FG) contains, in order from the object side, a negative first lens (L1) and a negative second lens (L2), and the back group (BG) contains a cemented lens (CL) constituted of at least three lenses (L5, L6, L7) joined together.

Abstract: An optical lens system with a wide field of view comprises, in order from the object side to the image side: a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a second lens element; a third lens element; a fourth lens element having a concave object-side surface and a convex image-side surface; a fifth lens element with positive refractive power; a sixth lens element with negative refractive power; a seventh lens element, one of an object-side surface and an image-side surface being aspheric. There are seven lens elements with refractive power. By adjusting the arrangement of curvature, refractive power of the respective lens elements and a stop, sufficient field of view can be obtained and the aberrations of the system can be corrected in order to obtain good image quality.

Abstract: An objective lens includes, in order from an object side, a front group having negative refractive power, an aperture stop, and a rear group having positive refractive power, wherein the front group includes, in order from the object side, a first lens which is a negative meniscus lens with a convex surface turned to the object side and a second lens which is a negative lens with a concave surface turned to the object side; the rear group includes, in order from the object side, a positive third lens and a fourth lens made up of a positive lens and a negative lens cemented together, and the objective lens satisfies conditional expression (1) below: ?0.8<f—F/f—R<?0.3 ??(1), where f_F is a focal length of the front group, and f_R is a focal length of the rear group.

Abstract: A wide-angle lens includes, in order from an object side, a first lens group G1 having negative refractive power, and a second lens group G2 having positive refractive power. The first lens group includes at least one negative meniscus lens having a convex surface facing the object side. The second lens group includes, in order from the object side, a positive lens, a negative lens and a positive lens. Given conditional expressions are satisfied.

Abstract: A projection optical system including a first optical system configured to form a second image conjugate to a first image and a second optical system configured to include a reflective optical element which reflects light from the second image and to project a third image conjugate to the second image onto a projection surface is provided, wherein the first optical system has a Petzval sum with a sign opposite to a sign of a Petzval sum of the second optical system.

Abstract: A wide angle lens module includes a first lens and a second lens with negative refracting power, a third lens and a fourth lens with positive refracting power, a fifth lens with negative refracting power, a sixth lens with positive refracting power, and a seventh lens with negative refracting power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are assembled in order from an object side to an image side.

Abstract: A fixed-focus 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 reduced side and includes a first lens and a second lens arranged in sequence from the magnified side to the reduced side. The refractive powers of both the first lens and the second lens are negative, and the first lens is an aspheric lens. The second lens group is disposed between the first lens group and the reduced side and includes a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged in sequence from the magnified side to the reduced side. The refractive powers of the seven lenses from the third lens to the ninth lens are respectively positive, negative, positive, negative, positive, negative, and positive in sequence.

Abstract: A wide angle lens module includes a first lens and a second lens with negative refracting power, a third lens and a fourth lens with positive refracting power, a fifth lens with negative refracting power, a sixth lens with positive refracting power, and a seventh lens with negative refracting power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are disposed in order from an object side to an image side.

Abstract: A fixed-focus lens suitable for projecting an image beam from a light valve onto a screen is provided. The fixed-focus lens comprises a first lens group, a second lens group, and a third lens group arranged in sequence. The third lens group is disposed near the light valve. The first lens group having a negative refractive power comprises at least an aspheric lens. The second lens group having a positive refractive power comprises at least a lens. The third lens group having a positive refractive power comprises at least four lenses.

Abstract: The invention relates to a compact image-formation optical system that is diminished in a diametrical direction with as few lenses as possible while well adapting to an wide-angle arrangement having a half angle of 90° or greater, and an imaging system incorporating the same. The image-formation optical system comprises, in order from its object side, a first lens L1 that is a negative lens, a second lens L2 that is a meniscus lens concave on its object side, an apertures stop S, and a lens group G having positive refracting power.