This paper extends classical object pose and relative camera motion estimation algorithms for imaging sensors sampling the scene through light-paths. Many algorithms in multi-view geometry assume that every pixel observes light traveling in a single line in space. We wish to relax this assumption and address various theoretical and practical issues in modeling camera rays as piece-wise linear-paths. Such paths consisting of finitely many linear segments are typical of any simple camera configuration with reflective and refractive elements. Our main contribution is to propose efficient algorithms that can work with the complete light-path without knowing the correspondence between their individual segments and the scene points. Second, we investigate light-paths containing infinitely many and small piece-wise linear segments that can be modeled using simple parametric curves such as conics. We show compelling simulations and real experiments, involving catadioptric configurations and mirages, to validate our study.