Pixel-to-pixel comparison of the blue area in Fig. 1 (NOAA AR 12960) for SDO/HMI (vector products) against SO/PHI-FDT. The original quantities are shown in the top row: B (panel A), γ (panel B), and B_LoS (panel C). The middle row displays the same quantities after convolving the original SDO/HMI data with the SO/PHI-FDT PSF (see text): B′ (panel D), γ′ (panel E), and (panel F). The total number of pixels compared in these plots is 4306. The blue lines depict linear fits. The dashed gray lines represent the identity function. The fits and Pearson correlation coefficients are given in the insets. The histograms of the differences between SDO/HMI and SO/PHI-FDT values are shown in the bottom row (panels G, H, and I). The dashed lines are skewed Gaussian fits to the histograms, with μ, σ, and η the mean standard deviations and skewness of the fit, respectively. The plots corresponding to the other active regions can be found in the Appendix A.