Photometric error profile for a sample field (b249). The 2D histogram in each panel displays the σ_Ks vs. K_s distribution of detected stars within a given detector (labeled in each panel). The color-coding indicates the density in each 2D histogram, from low (magenta) to very high (dark red) relative densities. The split or broadened sequences are due to the error mitigation in overlapping areas of a side ensemble. Detections in overlapping areas have smaller uncertainty. The black solid line refers to the combined errors: Δ_Ks vs. K_s, as calculated from the completeness experiments (except for detectors 04 and 16, for which no completeness is available).