Patent ID: 7848036

Claim:
An external lens mounting method for mounting an external lens in front of a lens of an image pickup device, said lens having a lens fastening part, said external lens mounting method comprising steps of: providing a fixer having an alignment slice and a fixing slot, wherein said alignment slice includes a first reference mark and a second reference mark, said first reference mark is enclosed by said second reference mark, and said first reference mark is arranged in a middle portion of said second reference mark; placing said fixer in front of said lens of said image pickup device, wherein an outer portion of said second reference mark of said alignment slice is parallel with said lens fastening part of said lens of said image pickup device, said first reference mark is aligned with a center of said lens of said image pickup device, and said second reference mark is concentric with said lens fastening part; moving said alignment slice such that said lens of said image pickup device is not sheltered by said alignment slice; and fixing said external lens in said fixing slot of said fixer.