Compact zoom lens

A zoom lens comprising:

• a first lens;
• a first lens barrel housing the first lens;
• a shutter assembly positioned on a distal end of the first lens barrel toward an object side of the zoom lens;
• a guide barrel received in the first lens barrel and configured for guiding the first lens barrel to move along the optical axis of the zoom lens;
• a second lens;
• a second lens barrel housing the second lens, wherein the first lens is positioned closer to the object side of the zoom lens than the second lens, the diameter of the first lens is greater than that of the second lens, the second lens barrel is received in the guide barrel and configured to be guided by the guide barrel to move along the optical axis of the zoom lens;
• a cam barrel receiving the first lens barrel and coupling with the first lens barrel and the second lens barrel, the cam barrel being configured to cause the first lens barrel and the second lens barrel to move relative to each other along the optical axis when being rotated to change the focal length of the zoom lens;
• a fixed barrel, wherein the fixed barrel defines a rotating track of the cam barrel, the cam barrel is received in the fixed barrel and capable of rotating along the rotating track to move along the optical axis of the zoom lens;
• a lens seating;
• a third lens fixed on the lens seating, wherein the lens seating is received in the fixed barrel;
• a driving device fixed to the fixed barrel and configured to rotate the cam barrel along the rotating track and move the lens seating along the optical axis;
• and
• a base fixed to a distal end of the fixed barrel that is close to an image side of the zoom lens;
• wherein the guide barrel comprises a barrel body, the first lens barrel, the barrel body, the second lens barrel, the cam barrel and the fixed barrel are all substantially tubular;
• the outer diameter of the second lens barrel is less than the inner diameter of the barrel body, the outer diameter of the barrel body is less than the inner diameter of the first lens barrel, the outer diameter of the first lens barrel is less than the inner diameter of the cam barrel, the outer diameter of the cam barrel is less than the inner diameter of the fixed barrel;
• wherein the guide barrel further comprises a flange extending outwards from an end of the barrel body that is close to the image side of the zoom lens, the flange comprises three first sliding pins protruding equidistantly from the edge thereof;
• the fixed barrel comprises three first guide slots defined on the inner side wall thereof, substantially parallel to the direction of the optical axis;
• each first sliding pin of the guide barrel is received in a corresponding one of the first guide slots.