In a previous paper, “On the Applicability of the Lorentz Transformations”, the issue of the physical vs. apparent velocity of a photon, c vs. (c±v), was examined in the cases of the emitter moving relative to the detector and vice versa. In the present paper, the case is examined of both the emitter and detector moving relative to the origin of a third coordinate system, the case used by Einstein for his derivation of the Lorentz transformations. It is shown that both Einstein’s derivation and a more general derivation are inconsistent with the behavior of the photon, and that the physical (not apparent) velocity of the photon as measured in the stationary coordinate system in this case must be (c±v). It is also noted that because the velocity of the photon is independent of its momentum and energy, the dispersion relations between conjugate Fourier variables of energy and time, ∇E∇t ≥ ħ/2, and momentum and position, ∇p∇x ≥ ħ/2, do not affect its velocity. As a result, unlike for non-zero rest mass quanta, the position of a photon as a function of time can in principle be determined with an arbitrary accuracy.