Due to the longitudinal polarized photon and scalar photon have been involved, both S and L are not gauge invariant. To incorporate the gauge invariance into the photon angular momenta, a re-decomposition of the total QED angular momentum and the Lorenz gauge condition have to be enforced. Finally, the direct observable part of spin and orbital angular momenta of light are given by S o b s = i ℏ ℏ ∫ ∫ d 3 k ( a ^ ^ k , 2 † † a ^ ^ k , 1 − − a ^ ^ k , 1 † † a ^ ^ k , 2 ) k | k | = ε ε 0 ∫ ∫ d 3 x E ⊥ ⊥ × × A ⊥ ⊥ , and L M o b s = ε ε 0 ∫ ∫ d 3 x E ⊥ ⊥ j x × × ∇ ∇ A ⊥ ⊥ j which recover the angular momenta of classical transverse light. Here, E ⊥ ⊥ ( A ⊥ ⊥ ) is the transverse part of the electric field (vector potential), ε ε 0 is the vacuum permittivity, and we are using SI units.