Interferometry objectives are used in non-contact optical profile measurement devices to obtain surface maps and surface measurement parameters. They can be used to examine surface topography with very high precision—to within a fraction of the wavelength of light. In these objectives, a light beam passes through a beamsplitter, which directs the light to both the surface of the sample and a built-in reference mirror. The light reflected from these surfaces recombines and a fringe interference pattern is formed. The Michelson objectives provide comparatively longer working distances, wider fields of view and larger depth of field, whereas the Mirau objectives are used in applications requiring higher magnification and/or numerical apertures. Use of the Nikon 200mm tube lens (#58-520) allows these objectives to be integrated to a C-Mount camera.