Optical lens and surveillance camera

The utility model provides an optical lens and a monitoring camera. The optical lens has an object side and an imaging side. The utility model relates to an optical lens which sequentially comprises a first plastic aspheric convex-concave negative-focal-power lens, a second plastic aspheric biconcave positive-focal-power lens, a third plastic aspheric biconcave positive-focal-power lens, a diaphragm, a fourth glass spherical biconvex positive-focal-power lens and a fifth plastic aspheric biconcave negative-focal-power lens. And a plastic aspheric biconvex sixth lens with positive focal power. The optical lens is simple in structure and low in cost. In addition, by reasonably distributing the focal power of the lenses in the lens, the lens is compact in structure, and the tolerance sensitivity of the lens is reduced. Furthermore, the plastic aspherical lens is reasonably used, so that the phase difference is well corrected. Furthermore, the focal length ratio of each lens is reasonably distributed, so that the