An apparatus for dental imaging comprises a light source for generating light, an optics system for focusing the light, and a probe head. The light source, the optics system and the probe head are arranged such that the light passes through the optics system, passes through the probe head, and exits the probe head. The optics system is configured such that chief rays of the light before entering the probe head are divergent to each other, wherein an angle defined by a marginal ray of an outermost beam of the light is complementary to an angle defined by an extreme off-axis chief ray of the light with respect to the optical axis.