Optical system

1 . An optical system, comprising:

a first lens group including a plurality of lenses; and

a second lens group including a plurality of lenses,

wherein the first lens group and the second lens group are disposed in order from an object side,

wherein among the lenses included in the second lens group, a lens disposed adjacent to a lens disposed farthest from the object side has an inflection point,

wherein each of the first lens group and the second lens group is configured to move in an optical axis direction to change a magnification between a wide-angle end and a telephoto end,

wherein G1F is a focal length of the first lens group, G2F is a focal length of the second lens group, and |G1F/G2F| has a value of between 0.5 and 1,

wherein the lenses of the first lens group are disposed with spaces therebetween along an optical axis,

wherein the lenses of the second lens group are disposed with spaces therebetween along the optical axis,

wherein the lens disposed adjacent to the lens disposed farthest from the object side has positive refractive power, and

wherein the lens disposed farthest from the object side has negative refractive power.

2 . The optical system of claim 1 , wherein the first lens group has positive refractive power, and the second lens group has negative refractive power.

3 . The optical system of claim 1 , wherein the entire number of lenses included in the first lens group and the second lens group is six, seven, or eight.

4 . The optical system of claim 1 , wherein the first lens group includes four or more lenses having refractive power, and the second lens group includes two or more lenses having refractive power.

5 . The optical system of claim 1 , wherein at least one of an object-side surface and an image-side surface of each of the lenses of the first lens group is aspherical, and at least one of an object-side surface and an image-side surface of each of the lenses of the second lens group is aspherical.

6 . The optical system of claim 1 , wherein G1_OAL is a distance between an object-side apex of a lens most adjacent to the object side among the lenses included in the first lens group and an image-side apex of a lens most adjacent to the image side among the lenses included in the first lens group, and G1_OAL is less than 10 mm.

7 . The optical system of claim 1 , wherein 1xL is a distance from an object-side surface of a lens most adjacent to the object side among the lenses of the first lens group at the wide-angle end to an imaging plane, 2xL is a distance from the object-side surface of the lens most adjacent to the object side at the telephoto end to the imaging plane, and 1xL/2xL is greater than 0.7.

8 . The optical system of claim 1 , wherein 1xB is a distance from an apex of an image-side surface of a lens most adjacent to the image side among the lenses of the second lens group at the wide-angle end to the imaging plane, 2xB is a distance from the apex of the image-side surface of the lens most adjacent to the image side at the telephoto end to the imaging plane, and 1xB/2xB is greater than 0.1.

9 . The optical system of claim 1 , wherein at least one of the object-side surface and the image-side surface of at least one of the lenses of the first lens group includes at least one inflection point, and at least one of the object-side surface and the image-side surface of at least one of the lenses of the second lens group includes at least one inflection point.

10 . The optical system of claim 1 , wherein the first lens group includes a first lens having positive refractive power, a second lens having refractive power, a third lens having refractive power, a fourth lens having refractive power, and a fifth lens having refractive power, disposed in order from the object side to the image side.

11 . The optical system of claim 1 , wherein the second lens group includes a sixth lens having refractive power and a seventh lens having positive refractive power, disposed in order from the object side to the image side.

12 . The optical system of claim 1 , further comprising:

an aperture stop disposed between the first lens group and the second lens group.

13 . An optical system, comprising:

a first lens group including at least one lens; and

a second lens group including at least one lens,

wherein the first lens group and the second lens group are disposed in order from an object side,

wherein each of the first lens group and the second lens group is configured to move in an optical axis direction to change a magnification between a wide-angle end and a telephoto end,

wherein G1F is a focal length of the first lens group, G2F is a focal length of the second lens group, and |G1F/G2F| has a value of between 0.5 and 1,

wherein the first lens group includes a first lens, a second lens, and a third lens disposed in order from the object side to the image side, and

wherein 1x_f is a focal length of the optical system at the wide-angle end, f3 is a focal length of the third lens, and |1x_f/f3| has a value of between 1 and 2.

14 . An optical system, comprising:

a first lens group including at least one lens; and

a second lens group including at least one lens,

wherein the first lens group and the second lens group are disposed in order from an object side,

wherein each of the first lens group and the second lens group is configured to move in an optical axis direction to change a magnification between a wide-angle end and a telephoto end,

wherein G1F is a focal length of the first lens group, G2F is a focal length of the second lens group, and |G1F/G2F| has a value of between 0.5 and 1,

wherein the first lens group includes a first lens, a second lens, and a third lens disposed in order from the object side to the image side, and

wherein 2x_f is a focal length of the optical system at the telephoto end, f3 is a focal length of the third lens, and |2x_f/f3| has a value of between 2 and 3.8.