Completeness over the field. Left panel: Completeness functions for 26 off-galaxy regions at various galactocentric radii estimated in a region of 6 × 6 arcmin² for the r-band. In red, all the regions with R_gal ≥ 30′, while functions at smaller galactocentric radii are plotted with gray lines. Right panel: radial trend of the interpolated 80% magnitude limit for each function. Blue open dots are the interpolated 80% magnitude limit for each region, while red dots are the values obtained through a running mean procedure with a window width of 4. The yellow region is ±0.1 mag around the red points.