Optical images of the fields of the two pulsars. Top panel: 3$\stackrel{\prime }{.}$05 × 3$\stackrel{\prime }{.}$05 image of the J0312 field obtained with the GTC/OSIRIS in the r′ band. Bottom panel: 2$\stackrel{\prime }{.}$8 × 1$\stackrel{\prime }{.}$4 FoV of the GTC/HiPERCAM in the g_s band containing J1627. The pulsars’ vicinities are shown with the boxes and enlarged in the insets to demonstrate the maximum (top) and minimum (bottom) brightness phases of their companions, whose positions are marked by blue circles. The positions of the stars used for the photometric calibration are marked by red circles. The star used to account for the changing weather conditions is shown with the green circle in the top panel. For J1627, for this purpose we used the same stars as for the photometric calibration.