A method of assembling a lens apparatus, the lens apparatus including first and second optical systems, first and second lens compartments which respectively retain the first and second optical systems, first and second lens frames which respectively correspond to, and respectively retain, the first and second lens compartments, a drive unit which moves at least one of the first and second optical systems to change the position of the at least one first and second optical systems, and a base member, the method comprising:
- fixing the drive unit to the base member;
- fixing the first and second lens frames to the base member;
- and
- respectively fixing the first and second lens compartments, respectively retaining the first and second optical systems, into the first and second lens frames after the drive unit and the first and second lens frames are fixed to the base member, wherein the lens apparatus has a first opening and a second opening, an optical axis extending through the first and second opening, and the step of respectively fixing the first and second lens compartments further comprises
- inserting the first and second lens compartments respectively through the first and second openings to reciprocate the first and second lens compartments into the lens apparatus along the optical axis.