Abstract: In a lens optical system having first, second, and third lenses that are arranged between an object and an image sensor where an image of the object is formed, in order from an object side, the first lens has a positive (+) refractive power and is convex toward the object, the second lens has a negative (?) refractive power and is convex toward the image sensor, and the third lens has a positive (+) refractive power and at least one of an incident surface and an exit surface of the third lens has at least one inflection point between a center portion and an edge thereof. The lens optical system satisfies the following inequality that 0.5<f1/f<0.8, in which f1 is a focal length of the first lens and f is a total focal length of the lens optical system.

Abstract: In a lens optical system having first, second, and third lenses that are arranged between an object and an image sensor where an image of the object is formed, in order from an object side, the first lens has a positive (+) refractive power and is convex toward the object, the second lens has a negative (?) refractive power and is convex toward the image sensor, and the third lens has a positive (+) refractive power and at least one of an incident surface and an exit surface of the third lens has at least one inflection point between a center portion and an edge thereof. The lens optical system satisfies the following inequality that 0.5<f1/f<0.8, in which f1 is a focal length of the first lens and f is a total focal length of the lens optical system.

Abstract: A photographic lens optical system including: a first lens, a second lens, and a third lens sequentially arranged from a side of an object toward an image sensor, wherein the first lens has a positive (+) refractive power and an incident surface that is convex toward the object, the second lens has a negative (?) refractive power and is convex toward the image sensor, the third lens has a negative (?) refractive power, and at least one of an incident surface and an exit surface thereof is aspherical, and wherein an angle of view (?) of the lens optical system, and a focal length (f) of the lens optical system satisfy the following inequality: 1.0<|tan ?|/f<2.0.

Abstract: A photographic lens optical system including: a first lens, a second lens, and a third lens sequentially arranged from a side of an object toward an image sensor, wherein the first lens has a positive (+) refractive power and an incident surface that is convex toward the object, the second lens has a negative (?) refractive power and is convex toward the image sensor, the third lens has a negative (?) refractive power, and at least one of an incident surface and an exit surface thereof is aspherical, and wherein an angle of view (?) of the lens optical system, and a focal length (f) of the lens optical system satisfy the following inequality: 1.0<|tan ?|/f<2.0.