Given an electromagnetic field by its components E and B. How is this related to probability amplitudes of a Schrödinger wave function for the same field. Trying the same or at least a similar question from a different angle: given the E and B field, can we derive from it, in principle, not considering solvability, the probability of registering a photon within a certain (small) volume and time interval? If not, which piece of information is missing. Yet another angle on the question: do the E and B field contain all the information for the probabilities or is there something missing?