Abstract: An improvement in a light collecting system for an agricultural seed monitor is disclosed. The light collecting system includes three optical surfaces: a convex lens surface, a planar surface, and a total internal reflection, cone condenser surface. The convex lens surface is designed to collect light from a seed sensing area of a seed tube and form a converging light beam. The converging beam is then incident onto the planar reflecting surface, which folds the optical axis of the converging light. The converging light beam is then incident onto a non-imaging, total internal reflection cone condenser surface. In a preferred embodiment all three optical surfaces are formed on a single prism made of plastic, with the convex lens being a spherical surface having a radius of curvature of about 20 mm, and the cone condenser surface having an input aperture diameter of about 6 mm and an output aperture diameter of about 0.9 mm.