The phenomenal operation of the LHC in Run-1 has allowed high precision measurements to be attained for single vector boson production in pp collisions. A new measurement of the cross section for Z\gamma production at \sqrt{s}=8 TeV will be presented triple differentially in dilepton invariant mass, |y| and \cos\theta covering the region 46<m<200 GeV; 0<|y|<3.6; and -1<cos\theta<+1. The measurement is designed to be simultaneously sensitive to the proton PDFs and to the weak mixing angle. A precision of better than 0.5% in the region m ~ mZ (excluding luminosity uncertainty) is achieved. An unfolded measurement of the Z forward-backward asymmetry is presented, and a novel method of extracting the effective weak mixing angle using this data will be discussed, together with plans from ATLAS to extract sin^2\theta_eff and test the consistency of the EW sector of the Standard Model.