Patent ID: 11885944
Assignee: ZHEJIANG SUNNY OPTICS CO., LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 11:
12. A zoom lens group, sequentially comprising, from an object side to an image side along an optical axis:
a first lens group with positive refractive power,
a second lens group with negative refractive power, and
a third lens group with positive refractive power,
wherein positions of the second lens group and the third lens group on the optical axis are adjustable; and
an effective focal length F1 of the first lens group and an effective focal length F3 of the third lens group meet 5.0<F1/F3<6.0,
the first lens group comprises a first lens with refractive power and a second lens with refractive power, which are sequentially arranged along the optical axis,
the second lens group comprises a third lens with negative refractive power and a fourth lens with refractive power, which are sequentially arranged along the optical axis,
an effective focal length f1 of the first lens, an effective focal length f2 of the second lens, an effective focal length f3 of the third lens and an effective focal length f4 of the fourth lens meet 2.5<(f2−f1)/(f4−f3)<5.5.