Chart showing the estimated uncertainties on the weighted mean G-band values as a function of magnitude. The colours represent the density of sources, from red (low) to blue (high). The distribution of sources has been flattened for this plot to make sure that features at all magnitudes were visible. For stars between magnitudes 12 and 16 the relation between estimated error and magnitude is close to what could be expected based on noise models. For fainter stars the effect of the background can be noted, while for brighter stars the estimated errors are larger than expected due to effects related to different gate settings and saturation. For a comparison with the expected errors see Evans et al. (2017).