An optical system has a first lens element (L1) having an outer portion
(36) and a first tapered surface (34). A second lens element (L2) has an
outer portion (26) and a second tapered surface (24). The first lens
element (L1) and the second lens element (L2) are spaced apart relative
to each other and centered relative to the optical axis (O) by a portion
of the first tapered surface (34) being in contact with a portion of the
second tapered surface (24), the outer portion (36) of the first lens
element (L1) being spaced apart from the outer portion (26) of the second
lens element (L2).