A phase difference detection apparatus for detecting a phase difference between images formed on a pair of optical sensor arrays in which the possibility of unproductive compensation is reduced by use of a compensation effectiveness judgment unit that judges whether or not compensation of a pair of image data rows would be effective. The upper projection is substantially tapered from the platform toward a cap. The telescopic lens system is combined with a digital camera system and an LCD display. The first hinge support includes a first hinge pin interface having a first hinge pin hole to receive a hinge pin.