The optical conductivity (sigma(1)) of SrTiO3 for various vacancies has been systematically studied using a combination of ultraviolet-vacuum ultraviolet reflectivity and spectroscopic ellipsometry. For cation (Ti) vacancies, sigma(1) shows large spectral weight transfer over a wide range of energy from as high as 35 eV to as low as 0.5 eV and the presence of mid-gap states, suggesting that strong correlations play an important role. Meanwhile, for anion (O) vacancies, sigma(1) shows changes from 7.4 eV up to 35 eV. (C) 2014 AIP Publishing LLC.