10x zoom ratio wide-angle zoom lens

A 10x ratio wide-angle zoom lens includes several lens sets which is made of several lenses with different focal lengths. It has a first lens set with a positive dioptre, a second lens set with a negative dioptre, a third lens set with a positive dioptre, and a fourth lens set with a positive dioptre. The second lens set further contains two lenses with negative dioptres and one lens with a positive dioptre. The lens with a positive dioptre has a non-spherical surface on the object side. The lens with a negative dioptre closer to the lens with a positive dioptre is cemented to the positive-dioptre lens. The fourth lens set contains a lens with a negative dioptre and two non-spherical surfaces. The wide-angle zoom lens moves the second and the fourth lens set along its optical axis to adjust its zoom and moves the fourth lens set to focus.