Zoom lens group

A zoom lens group, sequentially comprising from an object side to an image side along an optical axis:

• a first lens group having a negative refractive power, the first lens group comprising a first lens and a second lens which are sequentially arranged along the optical axis, wherein the first lens and the second lens are glued to form a first cemented lens;
• a second lens group having a positive refractive power, the second lens group comprising a third lens, a fourth lens and a fifth lens which are sequentially arranged along the optical axis, wherein the fourth lens and the fifth lens are glued to form a second cemented lens, an object-side surface of the fifth lens is concave surface, an object-side surface of the fourth lens is convex surface, an image-side surface of the fourth lens is convex surface;
• and
• a third lens group having a positive refractive power, the third lens group comprising a sixth lens;
• a separation distance between the first lens group and the second lens group on the optical axis and a separation distance between the second lens group and the third lens group on the optical axis are adjusted, so as to switch the zoom lens group from a wide-angle state to a long-focus state;
• and
• a total effective focal length FT of the zoom lens group in the long-focus state and a total effective focal length FW of the zoom lens group in the wide-angle state satisfy:
• FT/FW≥2.0,
• a curvature radius R9 of an object-side surface of the sixth lens and a curvature radius R10 of an image-side surface of the sixth lens satisfy:
• 1.32<R9/R10<1.4;
• a maximum field of view (FOVT) of the zoom lens group in the long-focus state satisfies:
• 10°<FOVT<13°;
• a curvature radius R4 of an object-side surface of the third lens and a curvature radius R6 of an object-side surface of the fourth lens satisfy:
• 0.59≤R4/R6<1.0;
• an effective focal length f21 of the third lens, an effective focal length f23 of the fifth lens and an effective focal length f22 of the fourth lens satisfy:
• 1.0<(f21+f23)/f22≤1.18;
• the total effective focal length FT of the zoom lens group in a long-focus state and an effective focal length F3 of the third lens group satisfy:
• 1.1<FT/F3≤1.38.