Digital camera focus assessment using a camera flange-mounted fiber optic probe

During the assembly of high-end digital cameras, it is necessary to determine the location and orientation of the imager plane in order to assess the camera's focusing capability. An apparatus based on non-coherent light interferometry has been developed, which performs these test immediately after the digital imager is installed into the camera body. The instrument includes a camera lens flange- mountable multipoint fiber optic probe, an optical multiplexer and a non-coherent light interferometer measurement system with LabWindows CVI software specifically developed for this purpose. This talk describes the principle of the measurement, the fiber optic probe design, and presents results demonstrating the performance capability of the apparatus.