Thin lens formula

Machine-translated from the French article

In optics, a conjugation relation or conjugation formula is a mathematical formula relating the position of an object to that of its image through an optical system. It takes its name from the fact that in geometrical optics, under conditions of stigmatism, that is when all the rays from an object point emerge at the output of the system at a single point, this point is called the conjugate image of the object point. The two points are then also said to be conjugate.