Zoom lens

The invention relates to a zoom lens. The zoom lens comprises a first fixed lens group with positive focal power, a zoom lens group with negative focal power, an aperture diaphragm, a second fixed lens group with positive focal power, a focusing lens group with positive focal power and a third fixed lens group with positive focal power which are sequentially arranged from an object side to an image side along an optical axis, wherein the zoom lens group and the focusing lens group can move along the optical axis direction, and the focusing lens group is composed of three lenses. On the premise that the zoom ratio of the zoom lens and the front-end aperture and the total length of the lens are mutually restricted, large-angle, small-size and low-distortion can still be realized, and high-resolution and full-focal-length 4K imaging in the whole zoom stroke can also be realized. 本发明涉及一种变焦镜头，包括沿光轴从物侧至像侧依次排列的光焦度为正的第一固定透镜群组、光焦度为负的变焦透镜群组、孔径光阑、光焦度为正的第二固定透镜群组、光焦度为正的对焦透镜群组和光焦度为正的第三固定透镜群组，所述变焦透镜群组和所述对焦透镜群组均可沿着光轴方向移动，所述对