Aperture correction as a function of (a) the circular aperture size and (b) annular aperture location. The circular aperture correction values are normalized to the effective velocity dispersion at R_e/2 (σ_e/2), following Cappellari et al. (2006). We also highlight the empirical mean circular aperture correction provided by Cappellari et al. (2006) for local E/S0 galaxies, with the shaded region representing its scatter. The numerical approximation for the annular aperture correction factors corresponds to that of Equation 1, using the input coefficients presented in Table 2.