An exemplary lens barrel includes a hollow main body. The hollow main body includes a first end at an object side, and an opposite second end at an image side. The hollow main body also including a cylindrical inner surface adjacent to the first end, a partially conical inner surface adjacent to the second end, and a ring-shaped groove located between the cylindrical inner surface and the partially conical inner surface. The partially conical inner surface faces toward the first end. A cone angle of the partially conical inner surface is in a range from 8 degrees to 16 degrees.