  Recent studies suggest that the cosmological constant affects the
gravitational bending of photons although the orbital equation for light in
Schwarzschild-de Sitter space time is free from cosmological constant. Here we
argued that the very notion of cosmological constant independency of photon
orbit in the Schwarzschild-de Sitter space time is not proper. Consequently the
cosmological constant has some clear contribution to the deflection angle of
light rays. We stressed the importance of the study of photon trajectories from
the reference objects in bending calculation, particularly for asymptotically
non-flat space-time. When such an aspect is taken in to consideration the
contribution of cosmological constant to the effective bending is found to
depend on the distances of the source and the reference objects.
