Patent ID: 7586700

Claim:
A method for adjusting an optical axis of an imaging optical system that comprises: a first lens element; a right-angle prism for bending light entered from the first lens at right angles; and a lens group that moves in a direction of an optical axis of the subject light emerged from the right-angle prism, wherein the imaging optical system is incorporated in a lens barrel, and the lens barrel comprises: a first holding member positioning and fixing the first lens and the right-angle prism; a second holding member incorporating the lens group; and an adjusting mechanism that adjusts the relative position of the first holding member with respect to the second holding member, the method comprising: when assembling the first holding member and the second holding member, positioning the first holding member relative to the second holding member; making inspection light incident into the first lens to pass through the first lens, the right-angle prism and the lens group in this order so that an image obtained from the inspection light takes a reference position; and changing a relative position of the first holding member with respect to the second holding member by adjusting the adjusting mechanism so as to coincide a first optical axis of the subject light emerged from the right-angle prism fixed to the first holding member, said first optical axis corresponding to the reference position, with a second optical axis of the lens group incorporated in the second holding member.