An optical lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The optical lens is capable of forming an image at the magnified side. F/H>0.52, where F is an effective focal length, and H is an image height. A viewing angle is greater than 116.7 degrees.