SpT-M_V calibrations for the 234 stars in the calibrator sample, with columns divided by LC groups. The top panels display the number of stars per SpT type bin. Dashed lines represent the synthetic photometry calibrations proposed by Martins & Plez (2006), while solid lines correspond to the calibrations derived in this work (see definitions in Table B.2). A triangle over the symbol indicates stars excluded from the fit by the σ-clipping procedure.