PSF reconstruction errors on the two ellipticity components, e₁ (left) and e₂ (right). These plots correspond to the two panels in the lower left corner of Fig. 4, but we now show the effect of changing the number of stars, N_⋆, used in the stack. Depending on the intrinsic ellipticity of the PSF (see Table 2), thousands of stars are needed to avoid being dominated by the shot noise.