  We study the effect of a weakly driven atomic cloud's polarization
distribution on its photon scattering lineshape. In doing this, we find three
distinct polarization regimes. First, for dilute clouds, the polarization
magnitude is relatively constant. Second, for denser clouds, polarization
builds at the front of the cloud for near-resonant light. Third, when the cloud
condenses to the point where its dimensions become comparable to the
wavelength, light refocuses towards the back of the cloud for red detuning. For
these regimes, we show which `mean-field' frameworks accurately describe the
differing photon scattering lineshapes. Finally, for even denser clouds, mean
field models become inaccurate and necessitate the full point dipole model that
includes atom-atom correlations.
