Top: Comparison between the PSF and Kron magnitudes from the Pan-STARRS catalog for the optical counterparts of VLASS compact sources. Their difference is negligible for point sources, while the fluxes of the extended sources are underestimated by PSF photometry. The two groups are well separated using a threshold of r_PSF − r_Kron = 0.3, valid down to r = 20.5. Bottom: Same as the top panel, but with the BZCAT sources highlighted.