Metallicity estimates, [Fe/H], from SPHINX, as a function of the biweight estimate from the SSPP, for stars of effective temperature 4500 < T_eff (K) < 6200. The gray region corresponds to the standard deviation of the residuals, determined from a maximum-likelihood Gaussian fit. Results from SPHINX using synthetic magnitudes from the SDSS Reservoir (left panels) are shown with the results from native J-PLUS DR1 photometry (right panels) for comparison.