Suppose you know the six cardinal points of an optical system (two focal points F1 and F2, two principal points H1 and H₂ and two nodal points N₁ and N₂), complete the three special rays to locate the image position formed by this system. Label the focal lengths, object distance and image distance. [Hint: A ray parallel to optical axis, turns to the focal point F2 after passing through the principle plane H₂. A ray through Fi will turn to parallel after H₁. A ray moving towards to Ni will emerge at N₂ with the same angle. In a thick lens, N overlaps with H point if the refractive index is the same on both sides of the lens.]

Suppose you know the six cardinal points of an optical system (two focal points F1 and F2, two principal points H1 and H₂ and two nodal points N₁ and N₂), complete the three special rays to locate the image position formed by this system. Label the focal lengths, object distance and image distance. [Hint: A ray parallel to optical axis, turns to the focal point F2 after passing through the principle plane H₂. A ray through Fi will turn to parallel after H₁. A ray moving towards to Ni will emerge at N₂ with the same angle. In a thick lens, N overlaps with H point if the refractive index is the same on both sides of the lens.]