Closed circuit television monitoring lens for realizing zooming of 12 times

The utility model discloses a closed circuit television monitoring lens for realizing zooming of 12 times; in a cavity of a lens barrel, a first lens group, a second lens group, a third lens group and a fourth lens group are sequentially arranged with the same optical axis and can do relative movement from an object direction to the lens direction; a light sensitive chip is arranged in the cavity of the lens barrel and below the fourth lens group; a diaphragm is arranged between the third lens group and the fourth lens group; the whole focal length of the first lens group is positive, the whole focal length of the second lens group is negative, the whole focal length of the third lens group is positive, the whole focal length of the fourth lens group is positive; and a first lens of the third lens group, facing the object direction, is a glass non-spherical lens, and the lens barrel is provided with a zooming motor for directly driving the second lens group to move and also provided with a focusing motor for