A dry objective includes: first lens group that includes a plurality of meniscus lens components and has a positive power; a second lens group that includes a cemented lens, turns a pencil of diverging light from the first lens group into a pencil of converging light, and has a positive power; and a third lens group that includes a front group and a rear group and has a negative power, the front and rear groups having concave surfaces adjacent to and facing each other. The dry objective satisfies the following conditional expression:
0.43≤(hg.sub.2−hg.sub.1)/gt.sub.1≤0.9  (1) where gt.sub.1 indicates a thickness that a lens component of the rear group that is the closest to the object has on an optical axis; hg.sub.1 and hg.sub.2, the heights of an axial marginal light ray at the lens surface of the lens component that is the closest to the object and an image.

A scope includes an objective lens system having refractive power, a relay lens system having refractive power, and an eyepiece system having refractive power. The relay lens system includes a first, a second, and a third lens groups. The second lens group includes a II-2-1 lens and a II-2-2 lens, and both of which are cemented. The third lens group includes a II-3-1 lens having a convex surface facing an object side and a II-3-2 lens having a convex surface facing an image side, and both of which are cemented. The second lens group and the third lens group can move along an optical axis to change a magnification of the relay lens system and thereby change a magnification of the scope. The objective lens system, the relay lens system, and the eyepiece system are arranged in order from the object side to the image side along the optical axis.

A scope includes an objective lens system having refractive power, a relay lens system having refractive power, and an eyepiece system having refractive power. The relay lens system includes a first, a second, and a third lens groups. The second lens group includes a II-2-1 lens and a II-2-2 lens, and both of which are cemented. The third lens group includes a II-3-1 lens having a convex surface facing an object side and a II-3-2 lens having a convex surface facing an image side, and both of which are cemented. The second lens group and the third lens group can move along an optical axis to change a magnification of the relay lens system and thereby change a magnification of the scope. The objective lens system, the relay lens system, and the eyepiece system are arranged in order from the object side to the image side along the optical axis.

A camera optical lens includes, from an object side to an image side, a first lens having a positive refractive power; a second lens having a negative refractive power; and a third lens having a positive refractive power, and satisfies: 0.65≤f1/f≤0.85; −0.90≤f2/f≤−0.60; 1.00≤f3/f≤1.20; −8.00≤(R5+R6)/(R5−R6)≤−2.50; 2.50≤d5/d4≤4.50; and 1.55≤n2≤1.70, where f, f1, f2, and f3 respectively denote focal lengths of the camera optical lens, the first lens, the second lens, and the third lens; R5 and R6 respectively denote central curvature radii of object side and image side surfaces of the third lens; d4 denotes an on-axis distance from an image side surface of the second lens to an object side surface of the third lens; d5 denotes an on-axis thickness of the third lens; and n2 denotes a refractive index of the second lens, thereby achieving good optical performance while meeting requirements of ultra-thinness and a wide angle.

A camera optical lens includes, from an object side to an image side, a first lens having a positive refractive power; a second lens having a negative refractive power; and a third lens having a positive refractive power, and satisfies: 0.65≤f1/f≤0.85; −0.90≤f2/f≤−0.60; 1.00≤f3/f≤1.20; −8.00≤(R5+R6)/(R5−R6)≤−2.50; 2.50≤d5/d4≤4.50; and 1.55≤n2≤1.70, where f, f1, f2, and f3 respectively denote focal lengths of the camera optical lens, the first lens, the second lens, and the third lens; R5 and R6 respectively denote central curvature radii of object side and image side surfaces of the third lens; d4 denotes an on-axis distance from an image side surface of the second lens to an object side surface of the third lens; d5 denotes an on-axis thickness of the third lens; and n2 denotes a refractive index of the second lens, thereby achieving good optical performance while meeting requirements of ultra-thinness and a wide angle.

A camera optical lens is provided, including from an object side to an image side: a first lens having positive refractive power; a second lens having negative refractive power; and a third lens having positive refractive power, wherein the camera optical lens satisfies following conditions: 0.75≤f1/f≤0.95; 1.20≤f3/f≤2.00; 0≤(R1+R2)/(R1−R2)≤0.80; −3.50≤(R3+R4)/(R3−R4)≤−1.50; −8.00≤(R5+R6)/(R5−R6)≤−2.50; and 1.50≤d5/d4≤4.00. The above camera optical lens can meet design requirements for large aperture, wide angle and ultra-thinness while maintaining good imaging performance.

A camera optical lens is provided, including from an object side to an image side: a first lens having positive refractive power; a second lens having negative refractive power; and a third lens having positive refractive power, wherein the camera optical lens satisfies following conditions: 0.75≤f1/f≤0.95; 1.20≤f3/f≤2.00; 0≤(R1+R2)/(R1−R2)≤0.80; −3.50≤(R3+R4)/(R3−R4)≤−1.50; −8.00≤(R5+R6)/(R5−R6)≤−2.50; and 1.50≤d5/d4≤4.00. The above camera optical lens can meet design requirements for large aperture, wide angle and ultra-thinness while maintaining good imaging performance.

A camera lens or lens group of reduced overall length includes a first lens with positive power, a second lens with negative power, a third lens with positive power, and an imaging element. The first, object side, lens includes a first surface and a second surface, the second lens includes a third surface and a fourth surface, and the third lens includes a fifth surface and a sixth surface. The camera lens satisfies conditions of 1.00<D/TTL<1.25; 0.85<|F1|/|F|<0.95; 3.85<|F2|/|F|<4.15; and 21.50<|F3|/|F|<27.50. D is the maximum imaging circle diameter on the imaging surface, TTL is the distance from the center point to the imaging side of the object-side surface of the first lens, F is the total focal length of the camera lens, F1 is the focal length of the first lens, F2 is the focal length of the second lens, and F3 is the focal length of the third lens.

A camera lens or lens group of reduced overall length includes a first lens with positive power, a second lens with negative power, a third lens with positive power, and an imaging element. The first, object side, lens includes a first surface and a second surface, the second lens includes a third surface and a fourth surface, and the third lens includes a fifth surface and a sixth surface. The camera lens satisfies conditions of 1.00<D/TTL<1.25; 0.85<|F1|/|F|<0.95; 3.85<|F2|/|F|<4.15; and 21.50<|F3|/|F|<27.50. D is the maximum imaging circle diameter on the imaging surface, TTL is the distance from the center point to the imaging side of the object-side surface of the first lens, F is the total focal length of the camera lens, F1 is the focal length of the first lens, F2 is the focal length of the second lens, and F3 is the focal length of the third lens.

Disclosed is an optical lens, from an object side to an image side including a first lens, a second lens and a third lens. The camera optical lens satisfies: 1.20≤f1/f≤1.80; −2.00≤f2/f≤−1.00; 0.75≤f3/f≤1.10; −6.00≤R2/R1≤−2.00; 2.20≤R4/R3≤8.00; 1.50≤d2/d4≤3.50; where f, f1, f2 and f3 denote a focal length of the camera optical lens, the first lens, the second lens and the third lens, respectively; R1, R2 denote a central curvature radius of an object-side surface and an image-side surface of the first lens, respectively; R3, R4 denote a central curvature radius of an object-side surface and an image-side surface of the second lens, respectively; d2 denotes an on-axis distance from the image-side surface of the first lens to the object-side surface of the second lens, and d4 denotes an on-axis distance from the image-side surface of the second lens to an object-side surface of the third lens.